Alkane coupling with CO_(2) by metal-containing zeolites catalysis is found to be a promising way to produce aromatics and syngas in recent years,but the real active sites and the role of CO_(2) are still unclear owin...Alkane coupling with CO_(2) by metal-containing zeolites catalysis is found to be a promising way to produce aromatics and syngas in recent years,but the real active sites and the role of CO_(2) are still unclear owing to the quick evolution of the metallic active sites and the complex reaction processes including direct propane aromatization,CO_(2) hydrogenation,reverse water-gas shift reaction,and propane-CO_(2) coupling aromatization.Herein,Ga/ZSM-5 catalysts were constructed to study the dynamic evolution of the metallic active sites and the role of CO_(2) during the propane and CO_(2) coupling reaction.After optimizing the reaction conditions,a notable propane conversion rate of 97.9%and an impressive aromatics selectivity of 80.6%in hydrocarbons can be achieved at the conditions of 550℃and CO_(2)/C_(3)H_(8) of 4.^(13)CO_(2)isotope experiments illustrate that C-atoms of CO_(2) can enter into CO(86.5%)and aromatics(10.8%)during the propane-CO_(2) coupling reaction process.In situ XANES and FTIR spectroscopies at 550℃and H_(2)/C_(3)H_(8) atmosphere reveal that GaO_(x) species can be gradually dispersed into[GaH_(2)]^(+)/[GaH]^(2+)on the Bronsted acid sites of ZSM-5 zeolite during H_(2) and/or C_(3)H_(8) treatment,which are the real active sites for propane-CO_(2) coupling conversion.In situ CO_(2)-FTIR experiments demonstrate that the[GaH_(2)]^(+)/[GaH]^(2+)species can react with CO_(2) and accelerate the propane and CO_(2) coupling process.This work not only presents a cost-effective avenue for CO_(2) utilization,but also contributes to the active site design for improved alkane and CO_(2) activation in coupling reaction system.展开更多
Spinel oxide(NiCo_(2)O_(4))has demonstrated great potential to replace noble metal catalysts for the oxidation reaction of air pollutants.To further boost the oxidation ability of such catalysts,in this study,a facile...Spinel oxide(NiCo_(2)O_(4))has demonstrated great potential to replace noble metal catalysts for the oxidation reaction of air pollutants.To further boost the oxidation ability of such catalysts,in this study,a facile surface-engineering strategy wherein NiCo_(2)O_(4) was treated with different alkali solvents was developed.The obtained catalyst(NiCo_(2)O_(4)-OH)showed a higher surface alkalinity and more surface defects compared to the pristine spinel oxide,including enhanced structural distortion as well as promoted oxygen vacancies.The propane oxidation ability of NiCo_(2)O_(4)-OH was greatly enhanced,with a propane conversion rate that was approximately 6.4 times higher than that of pristine NiCo_(2)O_(4) at a reaction temperature 193℃.This work sets a valuable paradigm for the surface modulation of spinel oxide via alkali treatment to ensure a high-performance oxidation catalyst.展开更多
Catalytic dehydrogenation represents one of the most effective methods for converting low-carbon hydrocarbons into monoolefins and hydrogen with identical carbon numbers.In this study,microporous(HZSMi)and meso-microp...Catalytic dehydrogenation represents one of the most effective methods for converting low-carbon hydrocarbons into monoolefins and hydrogen with identical carbon numbers.In this study,microporous(HZSMi)and meso-microporous molecular sieves(HZSMu)with a Si/Al atomic ratio of 150,synthesized in the laboratory,were prepared via hydrothermal synthesis.These supports were impregnated with 2.4%Co using the incipient wetness impregnation method and subsequently modified by introducing the metal additives Zr and Sn.Notably,the Co-Sn/HZSMu catalyst exhibited the highest stability,achieving a propylene selectivity of 95.3% within 400 min while maintaining robust activity.A series of characterization analyses reveal that the HZSMu molecular sieve possesses distinctive weaving properties.The synergistic effect between mesopores facilitates the adsorption and activation of reactants while preventing pore blockage,thus promoting the rapid diffusion of reactants on its surface.The incorporation of the metal additive Sn promotes the uniform dispersion of Co,mitigating the occurrence of side reactions and enhancing the catalytic performance and reaction stability of the catalyst.展开更多
Propane dehydrogenation(PDH)provides an alternative route to non-petroleum based propylene and eligible catalysts with good overall performance are still being explored.Herein,we report the construction of zeolite sta...Propane dehydrogenation(PDH)provides an alternative route to non-petroleum based propylene and eligible catalysts with good overall performance are still being explored.Herein,we report the construction of zeolite stabilized Pt-Zn catalysts Pt-Zn/Si-Beta for PDH.Characterization results from transmission electron microscopy(TEM),ultraviolet-visible(UV-vis)and Fourier transform infrared(FTIR)spectroscopy reveal that highly-dispersed Zn species are stabilized by the silanols from zeolite framework dealumination,which then act as the anchoring sites for Pt species.The close contact between Pt-Zn species and the electronic interaction thereof make Pt-Zn/Si-Beta robust PDH catalysts.Under optimized conditions,a high propylene production rate of 4.11 molmol_(Pt)^(-1)s^(-1),high propylene selectivity of 98% and a sustainable deactivation rate of~0.02 h^(-1)can be simultaneously achieved at 823 K.Coke deposition is not the key reason for the catalytic deactivation,while the loss of Zn species and the resulting aggregation of Pt species under high temperatures are responsible for the irreversible deactivation of Pt-Zn/Si-Beta catalyst in PDH reaction.展开更多
Oxide-Zeolite(OX-ZEO) bifunctional catalyst design concept has been exemplified in several processes to direct conversion syngas to value-added chemicals and fuels such as mixed light olefins, ethylene, aromatics and ...Oxide-Zeolite(OX-ZEO) bifunctional catalyst design concept has been exemplified in several processes to direct conversion syngas to value-added chemicals and fuels such as mixed light olefins, ethylene, aromatics and gasoline.Herein we demonstrate that the product can be steered toward liquefied petroleum gas(LPG) with a selectivity up to 89% in hydrocarbons especially propane selectivity reaching 80% at CO conversion of 63% using ZnCrOx-H-SSZ-39 catalyst.Interestingly, the quantity of the acid sites of SSZ-39 does not influence obviously the hydrocarbon distribution but the strength is crucial for selective formation of propane.This finding provides an alternative route of LPG synthesis from a variety of carbon resources via syngas.展开更多
Propane dehydrogenation(PDH), employing Pt-or Cr-based catalysts, represents an emerging industrial route for propylene production. Due to the scarcity of platinum and the toxicity of chromium, alternative PDH catalys...Propane dehydrogenation(PDH), employing Pt-or Cr-based catalysts, represents an emerging industrial route for propylene production. Due to the scarcity of platinum and the toxicity of chromium, alternative PDH catalysts are being pursued. Herein, we report the construction of Zn-containing zeolite catalysts,namely Zn@S-1, for PDH reaction. Well-isolated zinc cations are successfully trapped and stabilized by the Si-OH groups in S-1 zeolites via in-situ hydrothermal synthesis. The as-prepared Zn@S-1 catalysts exhibit good dehydrogenation activity, high propylene selectivity, and regeneration capability in PDH reaction under employed conditions. The in-situ partial reduction of zinc species is observed and the partially reduced zinc cations are definitely identified as the active sites for PDH reaction.展开更多
Pt-based catalysts are widely used in propane dehydrogenation reaction for the production of propylene.Suppressing irreversible deactivation caused by the sintering of Pt particles under harsh conditions and regenerat...Pt-based catalysts are widely used in propane dehydrogenation reaction for the production of propylene.Suppressing irreversible deactivation caused by the sintering of Pt particles under harsh conditions and regeneration process is a significant challenge in this catalyst.Herein,a series of highly ordered mesoporous Al_(2)O_(3) supports with different levels of Al3+penta sites,are fabricated and used as the support to disperse Pt-Sn_(2) clusters.Characterizations of Pt-Sn_(2)/meso-Al_(2)O_(3) with XRD,NMR,CO-IR,STEM,TG,and Raman techniques along with propane dehydrogenation-regeneration cycles test reveal the structure-stability-re generability relationship.The coordinatively unsaturated pentacoordinate Al_(Al3+penta)^(3+)can strongly anchor Pt atoms via a formation of Al-O-Pt bond,and thus stabilize the Pt-based particles at the surface of Al_(2)O_(3).The stability and regenerability of Pt-Sn2/meso-Al_(2)O_(3) are strongly dependent on the content of Al3+penta sites in the Al_(2)O_(3) structure,and a high level of Al3+penta sites can effectively prevent the agglomeration of Pt-Sn2 clusters into large Pt nanoparticles in the consecutive dehydrogenation-regeneration cycles.The Pt-Sn2/meso-Al_(2)O_(3)-600 with the highest level of Al_(penta)^(3+) (50.8%)delivers the best performance in propane dehydrogenation,which exhibits propane conversion of 40%and propylene selectivity above 98%at 570℃ with 10 vol%C_(3)H_(8) and 10 vol% H_(2) feed.A slow deactivation in this catalyst is ascribed to the formation of coke,and the catalytic performance can be fully restored in the consecutive dehydrogenation-regeneration cycles via a simple calcination treatment.展开更多
Propane dehydrogenation(PDH) provides an alternative route for producing propylene. Herein, we demonstrates that h-BN is a promising support of Pt-based catalysts for PDH. The Pt catalysts supported on h-BN were prepa...Propane dehydrogenation(PDH) provides an alternative route for producing propylene. Herein, we demonstrates that h-BN is a promising support of Pt-based catalysts for PDH. The Pt catalysts supported on h-BN were prepared by an impregnation method using Pt(NH_(3))_(4)(NO_(3))_(2) as metal precursors. It has been found that the Pt/BN catalyst undergoing calcination and reduction is highly stable in both PDH reaction and coke-burning regeneration, together with low coke deposition and outstanding propylene selectivity(99%). Detailed characterizations reveal that the high coke resistance and high propylene selectivity of the Pt/BN catalyst are derived not only from the absence of acidity on BN support, but also from the calcination-induced and reduction-adjusted strong metal-support interaction(SMSI) between Pt and BN, which causes the partial encapsulation of Pt particles by BO_(x) overlayers. The BO_(x) overlayers can block the low-coordinated Pt sites and constrain Pt particles into smaller ensembles, suppressing side reactions such as cracking and deep dehydrogenation. Moreover, the BO_(x) overlayers can effectively inhibit Pt sintering by the spatial isolation of Pt during periodic reaction-regeneration cycles. In this work, the catalyst support for PDH is expanded to nonoxide BN, and the understanding of SMSI between Pt and BN will provide rational design strategy for BN-based catalysts.展开更多
PtSnNaGa/ZSM-5 catalysts with different contents of Ga were prepared and characterized by X-ray diffraction (XRD), nitrogen adsorption, hydrogen chemisorption, ammonia temperature-programmed desorption (NH3-TPD), hydr...PtSnNaGa/ZSM-5 catalysts with different contents of Ga were prepared and characterized by X-ray diffraction (XRD), nitrogen adsorption, hydrogen chemisorption, ammonia temperature-programmed desorption (NH3-TPD), hydrogen temperature-programmed reduction (H2-TPR), and temperature-programmed oxidation (TPO) techniques. The performances of these catalysts for propane dehydrogenation were investigated. The test results indicated that the addition of Ga not only could improve the catalytic stability and propene selectivity, but also could effectively prevent the catalysts from coking. It was found that the PtSnNaGa(0.5 m%)/ZSM-5 catalyst exhibited the best performance in terms of propene selectivity and propane conversion. The high catalytic performance was most probably attributed to the presence of Ga that could strength- en the interaction between metals and the support to stabilize the catalytic active sites.展开更多
Highly ordered mesoporous NiMoO4 material was successfully synthesized using mesoporous silica KIT-6 as hard template via vacuum nanocasting method. The structure was characterized by means of XRD, TEM, N2 adsorption-...Highly ordered mesoporous NiMoO4 material was successfully synthesized using mesoporous silica KIT-6 as hard template via vacuum nanocasting method. The structure was characterized by means of XRD, TEM, N2 adsorption-desorption, Raman and FT-IR. The mesoporous NiMoO4 with the coexistence of a-NiMoO4 and fl-NiMoO4 showed well-ordered mesoporous structure, a bimodal pore size distribution and crystalline framework. The catalytic performance of NiMoOa was investigated for oxidative dehydrogenation of propane. It is demonstrated that the mesoporous NiMoO4 catalyst with more surface active oxygen species showed better catalytic performance in oxidative dehydrogena- tion of propane in comparison with bulk NiMoO4.展开更多
Dehydrogenation of propane(PDH)technology is one of the most promising on-purpose technologies to solve supply-demand unbalance of propylene.The industrial catalysts for PDH,such as Pt-and Cr-based catalysts,still hav...Dehydrogenation of propane(PDH)technology is one of the most promising on-purpose technologies to solve supply-demand unbalance of propylene.The industrial catalysts for PDH,such as Pt-and Cr-based catalysts,still have their own limitation in expensive price and security issues.Thus,a deep understanding into the structure-performance relationship of the catalysts during PDH reaction is necessary to achieve innovation in advanced high-efficient catalysts.In this review,we focused on discussion of structure-performance relationship of catalysts in PDH.Based on analysis of reaction mechanism and nature of active sites,we detailed interaction mechanism between structure of active sites and catalytic performance in metal catalysts and oxide catalysts.The relationship between coke deposition,co-feeding gas,catalytic activity and nanostructure of the catalysts are also highlighted.With these discussions on the relationship between structure and performances,we try to provide the insights into microstructure of active sites in PDH and the rational guidance for future design and development of PDH catalysts.展开更多
The catalytic properties of PtSn-based catalysts supported on siliceous SBA-15 and Al-modified SBA-15, such as Al-incorporated SBA-15 （AlSBA-15） and alumina-modified SBA-15 （Al2O3/SBA-15）, for propane dehydrogenat...The catalytic properties of PtSn-based catalysts supported on siliceous SBA-15 and Al-modified SBA-15, such as Al-incorporated SBA-15 （AlSBA-15） and alumina-modified SBA-15 （Al2O3/SBA-15）, for propane dehydrogenation were investigated. Al2O3/SBA-15 was prepared either by an impregnation method using aluminum nitrate aqueous solution, or by the treatment of SBA-15 with a Al（OC3H7）3 solution in anhydrous toluene. N2-physisorption, FT-IR spectroscopy, solid-state 27Al MAS NMR spectroscopy, hydrogen chemisorption, XRF, NH3 temperature-programmed desorption, X-ray photoelectron spectroscopy and TPO were used to characterize these samples. Among these catalysts, the PtSn-based catalyst supported on Al2O3/SBA-15, which was grafted with Al（OC3H7）3, exhibited the best catalytic performance in terms of activity and stability The possible reason was due to the high Pt metal dispersion and/or the strong interactions among Pt, Sn, and the support.展开更多
PtSnSr/HZSM-5 catalysts with different amounts of strontium were prepared by sequential impregnation method, and characterized by BET analysis, TEM, NH3-TPD, Hz-TPR, TPO and TG techniques. The results showed that the ...PtSnSr/HZSM-5 catalysts with different amounts of strontium were prepared by sequential impregnation method, and characterized by BET analysis, TEM, NH3-TPD, Hz-TPR, TPO and TG techniques. The results showed that the addition of strontium could modify the characteristics and properties of both acid function and metal function of Pt-Sn-based cata- lysts. In this case, PtSnSr/HZSM-5 catalyst with an appropriate amount of Sr （1.2%） showed higher catalytic activity and lower amount of coke deposits than PtSn/HZSM-5 catalyst. However, excessive loading of Sr could facilitate the reduction of Sn, which was unfavorable to the reaction. Afterwards, 1.0 m% of Na was added into the PtSnSr（1.2%）/HZSM-5 catalyst to improve the catalytic performance in propane dehydrogenation, and this catalyst displayed the best catalytic performance during our experiments. After having been subjected to reaction for 5 h, the PtSnNa（1.0%）Sr（1,2%）/HZSM-5 catalyst had achieved a higher than 95% selectivity towards propene along with a corresponding propane conversion rate of 32.2%.展开更多
Alumina materials are widely applied either as a catalyst or support in various industrial catalytic processes. Impurities in alumina that are unfriendly to catalytic performance are inevitably present during the prod...Alumina materials are widely applied either as a catalyst or support in various industrial catalytic processes. Impurities in alumina that are unfriendly to catalytic performance are inevitably present during the production processes. Facing this problem, we here report that the use of sulfur-containing alumina as the support can generate active alumina-supported platinum catalyst, which exhibits superior propylene selectivity and anti-coking ability during propane dehydrogenation. It demonstrated that the sulfur impurity in alumina is not entirely detrimental. During the reduction process, the formation of gas-phase sulfur species increased the electrons and poisoned unsaturated sites of platinum particles. The sulfur impurity in alumina can be removed through a hydrogen reduction process, and the degree of desulfurization is correlated with the operating temperature. This study demonstrated that the rational use of impurity will contribute to the design of a catalyst with high reactivity for potential applications.展开更多
The effect of cerium addition on the catalytic performance of propane dehydrogenation over PtSnNaIZSM-5 catalyst has been investigated by reaction tests and some physicochemical characterization such as XRD, BET, TEM,...The effect of cerium addition on the catalytic performance of propane dehydrogenation over PtSnNaIZSM-5 catalyst has been investigated by reaction tests and some physicochemical characterization such as XRD, BET, TEM, XPS, NH3-TPD, H2 chemisorption, TPR and TPO techniques. It has been found that with suitable amount of cerium addition, the platinum dispersion increased, while the carbon deposition tended to be eliminated easily. In these cases, the presence of cerium could not only realize the better distribution of metallic particles on the support, but also strengthen the interactions between Sn species and the support. Additionally, XPS spectra confirmed that more amounts of tin could exist in oxidized form, which was advantageous to the reaction. In our experiments, PtSnNaCe （1.1 wt%）/ZSM-5 catalyst exhibited the best catalytic performance. After running the reaction for 750 h, propane conversion was maintained higher than 30% with the corresponding selectivity to propylene of about 97%.展开更多
In this work, a series of Ni-Mo-Mg-O catalysts with mesoporous structure prepared by sol-gel method were investigated for the oxidative dehydrogenation of propane （ODHP）. The techniques of temperature-programmed red...In this work, a series of Ni-Mo-Mg-O catalysts with mesoporous structure prepared by sol-gel method were investigated for the oxidative dehydrogenation of propane （ODHP）. The techniques of temperature-programmed reduction with H2 （H2-TPR）, N2 adsorption-desolption, Fourier transform infrared spectroscopy （FT-IR）, X-ray diffraction （XRD） and X-ray photoelectron spectra （XPS） were employed for catalyst characterization. It is found that the activity of the catalysts for ODHP increases first and then decreases with the increase of Mo content. The catalyst with a Mo/Ni atomic ratio of 1/1 exhibits the best catalytic activity, which gives the propene selectivity of 81.4% at a propane conversion of 11.3% under 600 ~C and maintains the good catalytic performance for 22 h on stream. This is related not only to its high reducibility and dispersion as revealed by TPR and XRD, but also to the formation of more selective oxygen species on the MoOz-NiO interface as identified by XPS.展开更多
Ammonium salts, （NH4）6HPMo11MO40 （M = Ni, Co, Fe）, have been investigated for the oxidation of propane, with molecular oxygen, at temperature ranging between 380 ℃ and 420 ℃ after in-situ pre-treatment performed...Ammonium salts, （NH4）6HPMo11MO40 （M = Ni, Co, Fe）, have been investigated for the oxidation of propane, with molecular oxygen, at temperature ranging between 380 ℃ and 420 ℃ after in-situ pre-treatment performed at two heating rate of 5 or 9 ℃/min. They were characterized by BET method, XRD, 31p NMR, UV-Vis and IR techniques. The catalysts were found active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-treated with the heating rate of 9 ℃/min.展开更多
Mixed ammonium-transition metal salts with formula of （NH4）xMyHzPMo12O40 （M = Ni^2＋, Co^2＋ or Fe ^3＋） denoted as MPMo12 have been investigated for the oxidation of propane, with molecular oxygen, at temperature...Mixed ammonium-transition metal salts with formula of （NH4）xMyHzPMo12O40 （M = Ni^2＋, Co^2＋ or Fe ^3＋） denoted as MPMo12 have been investigated for the oxidation of propane, with molecular oxygen, at temperature range between 380 ℃ and 420 ℃ after in-situ pre-treatment performed at two heating rate of 5 or 9℃/min. They were characterized by BET method, XRD, UV-Vis and IR techniques. The catalysts were found to be active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-treated with the heating rate of 9℃/min. FePMo12 was found to be a more active catalyst for propene （17.2% yield） with minimal over deep oxidation （0.3% yield in COx）.展开更多
The alumina-modified SBA-15 （A12OJSBA-15） zeolite was prepared in a non-aqueous system by using toluene as the solvent, and was used to support the PtSn-based catalyst for propane dehydrogenation. The BET surface ar...The alumina-modified SBA-15 （A12OJSBA-15） zeolite was prepared in a non-aqueous system by using toluene as the solvent, and was used to support the PtSn-based catalyst for propane dehydrogenation. The BET surface area mea- surements, hydrogen chemisorption, FT-IR spectroscopy, NH3-TPD, XPS and TPO techniques were used to characterize the catalysts. Test results showed that the addition of alumina not only could modify the acid function of the support but also the structure of the metallic phase, thus affecting their catalytic properties. Among these catalysts studied, the PtSn/AI203 （5%）/ SBA-15 catalyst exhibited a best catalytic performance in terms of propane conversion and selectivity to propene. The high catalytic performance might be attributed to the relatively good Pt metal dispersion and/or the strong interaction between Pt and Sn species.展开更多
The effects of metal atomic ratio, water content, oxygen content, and calcination temperature on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic aci...The effects of metal atomic ratio, water content, oxygen content, and calcination temperature on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic acid have been investigated and discussed. Among the catalysts studied, it was found that the MoVTeNbO catalyst calcined at a temperature of 600 ℃ showed the best performance in terms of propane conversion and selectivity for acrylic acid under an atmosphere of nitrogen. An effective MoVTeNbO oxide catalyst for propane selective oxidation to acrylic acid was obtained with a combination of a preferred metal atomic ratio （Mo1V0.31Te0.23Nb0.12）. The optimum reaction condition for the selective oxidation of propane was the molar ratio of C3H8 ：O2 ： H2O ： N2 = 4.4： 12.8 ： 15.3 ： 36.9. Under such conditions, the conversion of propane and the maximum yield of acrylic acid reached about 50% and 21%, respectively.展开更多
基金supported by the National Key Research and Development Program of China (No.2022YFE0116000)the National Natural Science Foundation of China (No.22288101,21991092,21991090,22202193,and 22172166)+1 种基金the Youth Innovation Promotion Association CAS (2021182)the Innovation Research Foundation of Dalian Institute of Chemical Physics,Chinese Academy of Sciences (DICP I202429 and I202217)。
文摘Alkane coupling with CO_(2) by metal-containing zeolites catalysis is found to be a promising way to produce aromatics and syngas in recent years,but the real active sites and the role of CO_(2) are still unclear owing to the quick evolution of the metallic active sites and the complex reaction processes including direct propane aromatization,CO_(2) hydrogenation,reverse water-gas shift reaction,and propane-CO_(2) coupling aromatization.Herein,Ga/ZSM-5 catalysts were constructed to study the dynamic evolution of the metallic active sites and the role of CO_(2) during the propane and CO_(2) coupling reaction.After optimizing the reaction conditions,a notable propane conversion rate of 97.9%and an impressive aromatics selectivity of 80.6%in hydrocarbons can be achieved at the conditions of 550℃and CO_(2)/C_(3)H_(8) of 4.^(13)CO_(2)isotope experiments illustrate that C-atoms of CO_(2) can enter into CO(86.5%)and aromatics(10.8%)during the propane-CO_(2) coupling reaction process.In situ XANES and FTIR spectroscopies at 550℃and H_(2)/C_(3)H_(8) atmosphere reveal that GaO_(x) species can be gradually dispersed into[GaH_(2)]^(+)/[GaH]^(2+)on the Bronsted acid sites of ZSM-5 zeolite during H_(2) and/or C_(3)H_(8) treatment,which are the real active sites for propane-CO_(2) coupling conversion.In situ CO_(2)-FTIR experiments demonstrate that the[GaH_(2)]^(+)/[GaH]^(2+)species can react with CO_(2) and accelerate the propane and CO_(2) coupling process.This work not only presents a cost-effective avenue for CO_(2) utilization,but also contributes to the active site design for improved alkane and CO_(2) activation in coupling reaction system.
基金financially supported by the National Natural Science Foundation of China(No.22072069)the Key Laboratory of Hubei Province for Coal Conversion and New Carbon Materials(Wuhan University of Science and Technology No.WKDM202303).
文摘Spinel oxide(NiCo_(2)O_(4))has demonstrated great potential to replace noble metal catalysts for the oxidation reaction of air pollutants.To further boost the oxidation ability of such catalysts,in this study,a facile surface-engineering strategy wherein NiCo_(2)O_(4) was treated with different alkali solvents was developed.The obtained catalyst(NiCo_(2)O_(4)-OH)showed a higher surface alkalinity and more surface defects compared to the pristine spinel oxide,including enhanced structural distortion as well as promoted oxygen vacancies.The propane oxidation ability of NiCo_(2)O_(4)-OH was greatly enhanced,with a propane conversion rate that was approximately 6.4 times higher than that of pristine NiCo_(2)O_(4) at a reaction temperature 193℃.This work sets a valuable paradigm for the surface modulation of spinel oxide via alkali treatment to ensure a high-performance oxidation catalyst.
基金supported by the National Natural Science Foundation of China(Grant No.21968034).
文摘Catalytic dehydrogenation represents one of the most effective methods for converting low-carbon hydrocarbons into monoolefins and hydrogen with identical carbon numbers.In this study,microporous(HZSMi)and meso-microporous molecular sieves(HZSMu)with a Si/Al atomic ratio of 150,synthesized in the laboratory,were prepared via hydrothermal synthesis.These supports were impregnated with 2.4%Co using the incipient wetness impregnation method and subsequently modified by introducing the metal additives Zr and Sn.Notably,the Co-Sn/HZSMu catalyst exhibited the highest stability,achieving a propylene selectivity of 95.3% within 400 min while maintaining robust activity.A series of characterization analyses reveal that the HZSMu molecular sieve possesses distinctive weaving properties.The synergistic effect between mesopores facilitates the adsorption and activation of reactants while preventing pore blockage,thus promoting the rapid diffusion of reactants on its surface.The incorporation of the metal additive Sn promotes the uniform dispersion of Co,mitigating the occurrence of side reactions and enhancing the catalytic performance and reaction stability of the catalyst.
基金supported by the Municipal Natural Science Foundation of Tianjin(18JCJQJC47400,18JCZDJC37400)the National Postdoctoral Program for Innovative Talent(BX20200171)the Fundamental Research Funds for the Central Universities。
文摘Propane dehydrogenation(PDH)provides an alternative route to non-petroleum based propylene and eligible catalysts with good overall performance are still being explored.Herein,we report the construction of zeolite stabilized Pt-Zn catalysts Pt-Zn/Si-Beta for PDH.Characterization results from transmission electron microscopy(TEM),ultraviolet-visible(UV-vis)and Fourier transform infrared(FTIR)spectroscopy reveal that highly-dispersed Zn species are stabilized by the silanols from zeolite framework dealumination,which then act as the anchoring sites for Pt species.The close contact between Pt-Zn species and the electronic interaction thereof make Pt-Zn/Si-Beta robust PDH catalysts.Under optimized conditions,a high propylene production rate of 4.11 molmol_(Pt)^(-1)s^(-1),high propylene selectivity of 98% and a sustainable deactivation rate of~0.02 h^(-1)can be simultaneously achieved at 823 K.Coke deposition is not the key reason for the catalytic deactivation,while the loss of Zn species and the resulting aggregation of Pt species under high temperatures are responsible for the irreversible deactivation of Pt-Zn/Si-Beta catalyst in PDH reaction.
基金supported by the Ministry of Science and Technology of China (No.2017YFB0602201)the Chinese Academy of Sciences (XDA21020400)+2 种基金the National Natural Science Foundation of China (Grant nos.91645204, 21425312 and 21621063)the Youth Innovation Promotion Association of Chinese Academy of Sciences (2019184)the INCOE (International Network of Centers of Excellence) project coordinated by BASF SE
文摘Oxide-Zeolite(OX-ZEO) bifunctional catalyst design concept has been exemplified in several processes to direct conversion syngas to value-added chemicals and fuels such as mixed light olefins, ethylene, aromatics and gasoline.Herein we demonstrate that the product can be steered toward liquefied petroleum gas(LPG) with a selectivity up to 89% in hydrocarbons especially propane selectivity reaching 80% at CO conversion of 63% using ZnCrOx-H-SSZ-39 catalyst.Interestingly, the quantity of the acid sites of SSZ-39 does not influence obviously the hydrocarbon distribution but the strength is crucial for selective formation of propane.This finding provides an alternative route of LPG synthesis from a variety of carbon resources via syngas.
基金National Natural Science Fund of China(22025203, 21872072)the Municipal Natural Science Fund of Tianjin (18JCJQJC47400) for supporting the work。
文摘Propane dehydrogenation(PDH), employing Pt-or Cr-based catalysts, represents an emerging industrial route for propylene production. Due to the scarcity of platinum and the toxicity of chromium, alternative PDH catalysts are being pursued. Herein, we report the construction of Zn-containing zeolite catalysts,namely Zn@S-1, for PDH reaction. Well-isolated zinc cations are successfully trapped and stabilized by the Si-OH groups in S-1 zeolites via in-situ hydrothermal synthesis. The as-prepared Zn@S-1 catalysts exhibit good dehydrogenation activity, high propylene selectivity, and regeneration capability in PDH reaction under employed conditions. The in-situ partial reduction of zinc species is observed and the partially reduced zinc cations are definitely identified as the active sites for PDH reaction.
基金Financial supports of the National Natural Science Foundation of China(21878050,91934301)the State Key Laboratory of Coal Conversion(J21-22-620)the 111 Project(D17005)。
文摘Pt-based catalysts are widely used in propane dehydrogenation reaction for the production of propylene.Suppressing irreversible deactivation caused by the sintering of Pt particles under harsh conditions and regeneration process is a significant challenge in this catalyst.Herein,a series of highly ordered mesoporous Al_(2)O_(3) supports with different levels of Al3+penta sites,are fabricated and used as the support to disperse Pt-Sn_(2) clusters.Characterizations of Pt-Sn_(2)/meso-Al_(2)O_(3) with XRD,NMR,CO-IR,STEM,TG,and Raman techniques along with propane dehydrogenation-regeneration cycles test reveal the structure-stability-re generability relationship.The coordinatively unsaturated pentacoordinate Al_(Al3+penta)^(3+)can strongly anchor Pt atoms via a formation of Al-O-Pt bond,and thus stabilize the Pt-based particles at the surface of Al_(2)O_(3).The stability and regenerability of Pt-Sn2/meso-Al_(2)O_(3) are strongly dependent on the content of Al3+penta sites in the Al_(2)O_(3) structure,and a high level of Al3+penta sites can effectively prevent the agglomeration of Pt-Sn2 clusters into large Pt nanoparticles in the consecutive dehydrogenation-regeneration cycles.The Pt-Sn2/meso-Al_(2)O_(3)-600 with the highest level of Al_(penta)^(3+) (50.8%)delivers the best performance in propane dehydrogenation,which exhibits propane conversion of 40%and propylene selectivity above 98%at 570℃ with 10 vol%C_(3)H_(8) and 10 vol% H_(2) feed.A slow deactivation in this catalyst is ascribed to the formation of coke,and the catalytic performance can be fully restored in the consecutive dehydrogenation-regeneration cycles via a simple calcination treatment.
基金financially supported by the National Natural Science Foundation of China(21273049,22172037)the Guangdong Basic and Applied Basic Research Foundation(2021A1515010014)+1 种基金the Science and Technology Program of Guangzhou(201904010023)the CAS Key Laboratory of Renewable Energy(E029kf0901)。
文摘Propane dehydrogenation(PDH) provides an alternative route for producing propylene. Herein, we demonstrates that h-BN is a promising support of Pt-based catalysts for PDH. The Pt catalysts supported on h-BN were prepared by an impregnation method using Pt(NH_(3))_(4)(NO_(3))_(2) as metal precursors. It has been found that the Pt/BN catalyst undergoing calcination and reduction is highly stable in both PDH reaction and coke-burning regeneration, together with low coke deposition and outstanding propylene selectivity(99%). Detailed characterizations reveal that the high coke resistance and high propylene selectivity of the Pt/BN catalyst are derived not only from the absence of acidity on BN support, but also from the calcination-induced and reduction-adjusted strong metal-support interaction(SMSI) between Pt and BN, which causes the partial encapsulation of Pt particles by BO_(x) overlayers. The BO_(x) overlayers can block the low-coordinated Pt sites and constrain Pt particles into smaller ensembles, suppressing side reactions such as cracking and deep dehydrogenation. Moreover, the BO_(x) overlayers can effectively inhibit Pt sintering by the spatial isolation of Pt during periodic reaction-regeneration cycles. In this work, the catalyst support for PDH is expanded to nonoxide BN, and the understanding of SMSI between Pt and BN will provide rational design strategy for BN-based catalysts.
基金supports provided by the Production and Research Prospective Joint Research Project (BY2009153)the Science and Technology Support Program (BE2008129)of jiansu Province of chinathe National Natural Science Foundation of China(50873026)
文摘PtSnNaGa/ZSM-5 catalysts with different contents of Ga were prepared and characterized by X-ray diffraction (XRD), nitrogen adsorption, hydrogen chemisorption, ammonia temperature-programmed desorption (NH3-TPD), hydrogen temperature-programmed reduction (H2-TPR), and temperature-programmed oxidation (TPO) techniques. The performances of these catalysts for propane dehydrogenation were investigated. The test results indicated that the addition of Ga not only could improve the catalytic stability and propene selectivity, but also could effectively prevent the catalysts from coking. It was found that the PtSnNaGa(0.5 m%)/ZSM-5 catalyst exhibited the best performance in terms of propene selectivity and propane conversion. The high catalytic performance was most probably attributed to the presence of Ga that could strength- en the interaction between metals and the support to stabilize the catalytic active sites.
基金supported by NSFC(21073235,21173270,21177160,21376261)863 Program(2013AA065302)PetroChina Innovation Foundation(2011D-5006-0403)
文摘Highly ordered mesoporous NiMoO4 material was successfully synthesized using mesoporous silica KIT-6 as hard template via vacuum nanocasting method. The structure was characterized by means of XRD, TEM, N2 adsorption-desorption, Raman and FT-IR. The mesoporous NiMoO4 with the coexistence of a-NiMoO4 and fl-NiMoO4 showed well-ordered mesoporous structure, a bimodal pore size distribution and crystalline framework. The catalytic performance of NiMoOa was investigated for oxidative dehydrogenation of propane. It is demonstrated that the mesoporous NiMoO4 catalyst with more surface active oxygen species showed better catalytic performance in oxidative dehydrogena- tion of propane in comparison with bulk NiMoO4.
基金supported by the National Natural Science Foundation of China(21872163,21972166)National Engineering Laboratory for Mobile Source Emission Control Technology(NELMS2017A05)+1 种基金Beijing Natural Science Foundation(2202045,2182060)PetroChina Innovation Foundation(2018D-5007-0505)
文摘Dehydrogenation of propane(PDH)technology is one of the most promising on-purpose technologies to solve supply-demand unbalance of propylene.The industrial catalysts for PDH,such as Pt-and Cr-based catalysts,still have their own limitation in expensive price and security issues.Thus,a deep understanding into the structure-performance relationship of the catalysts during PDH reaction is necessary to achieve innovation in advanced high-efficient catalysts.In this review,we focused on discussion of structure-performance relationship of catalysts in PDH.Based on analysis of reaction mechanism and nature of active sites,we detailed interaction mechanism between structure of active sites and catalytic performance in metal catalysts and oxide catalysts.The relationship between coke deposition,co-feeding gas,catalytic activity and nanostructure of the catalysts are also highlighted.With these discussions on the relationship between structure and performances,we try to provide the insights into microstructure of active sites in PDH and the rational guidance for future design and development of PDH catalysts.
基金supported by the National Nature Science Foundation of China (50873026, 21106017)the Production and Research Prospective Joint Research Project (BY2009153)+1 种基金the Science and Technology Support Program (BE2008129) of Jiangsu Province of ChinaSpecialized Research Fund for the Doctoral Program of Higher Education of China (20100092120047)
文摘The catalytic properties of PtSn-based catalysts supported on siliceous SBA-15 and Al-modified SBA-15, such as Al-incorporated SBA-15 （AlSBA-15） and alumina-modified SBA-15 （Al2O3/SBA-15）, for propane dehydrogenation were investigated. Al2O3/SBA-15 was prepared either by an impregnation method using aluminum nitrate aqueous solution, or by the treatment of SBA-15 with a Al（OC3H7）3 solution in anhydrous toluene. N2-physisorption, FT-IR spectroscopy, solid-state 27Al MAS NMR spectroscopy, hydrogen chemisorption, XRF, NH3 temperature-programmed desorption, X-ray photoelectron spectroscopy and TPO were used to characterize these samples. Among these catalysts, the PtSn-based catalyst supported on Al2O3/SBA-15, which was grafted with Al（OC3H7）3, exhibited the best catalytic performance in terms of activity and stability The possible reason was due to the high Pt metal dispersion and/or the strong interactions among Pt, Sn, and the support.
基金The Production and Research Prospective Joint Research Project (BY2009153)The Science and Technology Support Program (BE2008129) of Jiangsu Province of Chinathe National Nature Science Foundation of China (50873026,21106017) for financial support
文摘PtSnSr/HZSM-5 catalysts with different amounts of strontium were prepared by sequential impregnation method, and characterized by BET analysis, TEM, NH3-TPD, Hz-TPR, TPO and TG techniques. The results showed that the addition of strontium could modify the characteristics and properties of both acid function and metal function of Pt-Sn-based cata- lysts. In this case, PtSnSr/HZSM-5 catalyst with an appropriate amount of Sr （1.2%） showed higher catalytic activity and lower amount of coke deposits than PtSn/HZSM-5 catalyst. However, excessive loading of Sr could facilitate the reduction of Sn, which was unfavorable to the reaction. Afterwards, 1.0 m% of Na was added into the PtSnSr（1.2%）/HZSM-5 catalyst to improve the catalytic performance in propane dehydrogenation, and this catalyst displayed the best catalytic performance during our experiments. After having been subjected to reaction for 5 h, the PtSnNa（1.0%）Sr（1,2%）/HZSM-5 catalyst had achieved a higher than 95% selectivity towards propene along with a corresponding propane conversion rate of 32.2%.
基金supported by the National Key Research and Development Project(2018YFA0209404)the State Key Program of the National Natural Science Foundation of China(21733002)the National Natural Science Foundation of China(U1908203)。
文摘Alumina materials are widely applied either as a catalyst or support in various industrial catalytic processes. Impurities in alumina that are unfriendly to catalytic performance are inevitably present during the production processes. Facing this problem, we here report that the use of sulfur-containing alumina as the support can generate active alumina-supported platinum catalyst, which exhibits superior propylene selectivity and anti-coking ability during propane dehydrogenation. It demonstrated that the sulfur impurity in alumina is not entirely detrimental. During the reduction process, the formation of gas-phase sulfur species increased the electrons and poisoned unsaturated sites of platinum particles. The sulfur impurity in alumina can be removed through a hydrogen reduction process, and the degree of desulfurization is correlated with the operating temperature. This study demonstrated that the rational use of impurity will contribute to the design of a catalyst with high reactivity for potential applications.
基金supported by the National Natural Science Foundation of China (Grant No. 50873026 and 21106017)the Production and Research Prospective Joint Research Project of Jiangsu Province of China (Grant No. BY2009153)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20100092120047)
文摘The effect of cerium addition on the catalytic performance of propane dehydrogenation over PtSnNaIZSM-5 catalyst has been investigated by reaction tests and some physicochemical characterization such as XRD, BET, TEM, XPS, NH3-TPD, H2 chemisorption, TPR and TPO techniques. It has been found that with suitable amount of cerium addition, the platinum dispersion increased, while the carbon deposition tended to be eliminated easily. In these cases, the presence of cerium could not only realize the better distribution of metallic particles on the support, but also strengthen the interactions between Sn species and the support. Additionally, XPS spectra confirmed that more amounts of tin could exist in oxidized form, which was advantageous to the reaction. In our experiments, PtSnNaCe （1.1 wt%）/ZSM-5 catalyst exhibited the best catalytic performance. After running the reaction for 750 h, propane conversion was maintained higher than 30% with the corresponding selectivity to propylene of about 97%.
基金supported by the National Natural Science Foundation of China (20776089)the New Century Excellent Talent Project of China(NCET-05-0783)
文摘In this work, a series of Ni-Mo-Mg-O catalysts with mesoporous structure prepared by sol-gel method were investigated for the oxidative dehydrogenation of propane （ODHP）. The techniques of temperature-programmed reduction with H2 （H2-TPR）, N2 adsorption-desolption, Fourier transform infrared spectroscopy （FT-IR）, X-ray diffraction （XRD） and X-ray photoelectron spectra （XPS） were employed for catalyst characterization. It is found that the activity of the catalysts for ODHP increases first and then decreases with the increase of Mo content. The catalyst with a Mo/Ni atomic ratio of 1/1 exhibits the best catalytic activity, which gives the propene selectivity of 81.4% at a propane conversion of 11.3% under 600 ~C and maintains the good catalytic performance for 22 h on stream. This is related not only to its high reducibility and dispersion as revealed by TPR and XRD, but also to the formation of more selective oxygen species on the MoOz-NiO interface as identified by XPS.
文摘Ammonium salts, （NH4）6HPMo11MO40 （M = Ni, Co, Fe）, have been investigated for the oxidation of propane, with molecular oxygen, at temperature ranging between 380 ℃ and 420 ℃ after in-situ pre-treatment performed at two heating rate of 5 or 9 ℃/min. They were characterized by BET method, XRD, 31p NMR, UV-Vis and IR techniques. The catalysts were found active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-treated with the heating rate of 9 ℃/min.
文摘Mixed ammonium-transition metal salts with formula of （NH4）xMyHzPMo12O40 （M = Ni^2＋, Co^2＋ or Fe ^3＋） denoted as MPMo12 have been investigated for the oxidation of propane, with molecular oxygen, at temperature range between 380 ℃ and 420 ℃ after in-situ pre-treatment performed at two heating rate of 5 or 9℃/min. They were characterized by BET method, XRD, UV-Vis and IR techniques. The catalysts were found to be active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-treated with the heating rate of 9℃/min. FePMo12 was found to be a more active catalyst for propene （17.2% yield） with minimal over deep oxidation （0.3% yield in COx）.
基金the National Nature Science Foundation of China (50873026, 21106017)the Production and Research Prospective Joint Research Project (BY2009153)+1 种基金the Science and Technology Support Program (BE2008129) of Jiangsu Province of Chinathe Specialized Research Fund for the Doctoral Program of Higher Education of China (20100092120047) for financial supports
文摘The alumina-modified SBA-15 （A12OJSBA-15） zeolite was prepared in a non-aqueous system by using toluene as the solvent, and was used to support the PtSn-based catalyst for propane dehydrogenation. The BET surface area mea- surements, hydrogen chemisorption, FT-IR spectroscopy, NH3-TPD, XPS and TPO techniques were used to characterize the catalysts. Test results showed that the addition of alumina not only could modify the acid function of the support but also the structure of the metallic phase, thus affecting their catalytic properties. Among these catalysts studied, the PtSn/AI203 （5%）/ SBA-15 catalyst exhibited a best catalytic performance in terms of propane conversion and selectivity to propene. The high catalytic performance might be attributed to the relatively good Pt metal dispersion and/or the strong interaction between Pt and Sn species.
文摘The effects of metal atomic ratio, water content, oxygen content, and calcination temperature on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic acid have been investigated and discussed. Among the catalysts studied, it was found that the MoVTeNbO catalyst calcined at a temperature of 600 ℃ showed the best performance in terms of propane conversion and selectivity for acrylic acid under an atmosphere of nitrogen. An effective MoVTeNbO oxide catalyst for propane selective oxidation to acrylic acid was obtained with a combination of a preferred metal atomic ratio （Mo1V0.31Te0.23Nb0.12）. The optimum reaction condition for the selective oxidation of propane was the molar ratio of C3H8 ：O2 ： H2O ： N2 = 4.4： 12.8 ： 15.3 ： 36.9. Under such conditions, the conversion of propane and the maximum yield of acrylic acid reached about 50% and 21%, respectively.
