The utilization of solar energy for hydrogen production via water splitting has garnered considerable attention in the realm of renewable energy.Si nanowires photocathodes own the advantages of effective photon absorp...The utilization of solar energy for hydrogen production via water splitting has garnered considerable attention in the realm of renewable energy.Si nanowires photocathodes own the advantages of effective photon absorption,non toxicity and industrial applicability.Nevertheless,the photoelectrocatalytic(PEC)performance of Si nanowires photocathodes is still limited by ineffective or deficient active sites on their surfaces.Here,we develop an efficient Si based photocathode modified with Al-porphyrin-based MOF(Al-PMOF),consisted of an earth-abundant metal containing Al(OH)O_(4) cluster bridged by 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin.The assembled Al-PMOF significantly enhances the photocurrent density of bare Si nanowires photocathodes,resulting in a twofold increase under equivalent conditions,alongside a positive shift of 200 mV in the onset potential of the Si/Al-PMOF photocathode.The improved PEC hydrogen evolution performance is ascribed to accelerate surface charge transfer of Si photocathode and provision of favorable active site for the hydrogen evolution reaction.This work provides insights into the fabrication of semiconductor/molecule catalyst hybrid photocathodes,thus facilitating the realization of high-efficiency PEC water splitting.展开更多
Preparation of highly active hydrodesulfurization catalysts is extremely meaningful for the sulfur removal from thiophene substances.In this work,commercial nano-Al_(2)O_(3)with mesoporous structure supported monometa...Preparation of highly active hydrodesulfurization catalysts is extremely meaningful for the sulfur removal from thiophene substances.In this work,commercial nano-Al_(2)O_(3)with mesoporous structure supported monometallic phosphide(NiP/Al_(2)O_(3)and MoP/Al_(2)O_(3))and bimetallic phosphide(NiMoP/Al_(2)O_(3)with various Ni/Mo molar ratio)catalysts are successfully prepared by temperature-programmed reduction.X-ray diffraction(XRD)result shows the Ni/Mo molar ratio affect the crystal phase in catalysts.Scanning electron microscopy(SEM),transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS)characterizations co-confirm the interact between Ni and Mo elements in bimetallic phosphide.Catalyst evaluation in hydrodesulfurization of dibenzothiophene shows that bimetallic phosphide samples exhibit better catalytic performance than monometallic phosphide.62.1%conversion and 86.3%biphenyl selectivity with 30 h stability are achieved over NiMoP/Al_(2)O_(3)(Ni/Mo=1∶1)catalyst at 400℃under 3 MPa H_(2).All characterization results demonstrate that the improved activity of bimetallic phosphide owes to the Ni-Mo synergistic effect in NiMoP/Al_(2)O_(3)(Ni/Mo=1∶1)catalyst.This finding provides a guide to the design of bimetallic catalyst with synergistic effect.展开更多
Metal hydroxides （MAH） consisting of magnesium hydroxide and aluminum hydroxide with a mass ratio of 1：2 were surface-modified by y-diethoxyphosphorous ester propyldiethoxymethylsilane, boric acid and diphenylsilan...Metal hydroxides （MAH） consisting of magnesium hydroxide and aluminum hydroxide with a mass ratio of 1：2 were surface-modified by y-diethoxyphosphorous ester propyldiethoxymethylsilane, boric acid and diphenylsilanediol in xylene under dibutyl tin dilaurate catalyst at 140 ℃. Phosphorus, silicon and boron elements covalently bonded to metal hydroxide particles were detected by X-ray photoelectron spectroscopy. The degradation behavior of the surface-modified MAH was characterized by thermogravimetric analysis. The results show that linear low density polyethylene （LLDPE） composite, filled with 50% （mass fraction） of MAH modified by 5.0% （mass fraction） of modifiers, passes the V-0 rating of UL-94 test and shows the limited oxygen index of 34%, and its heat release rate and average effective heat combustion in a cone calorimeter measurement decrease obviously; The mechanical properties of MAH can be improved by surface-modification. The uniform dispersion of particles and strong interfacial bonding between particles and matrix are obtained.展开更多
Transition metal sulfides(TMSs)-based materials have been extensively investigated as effective non-noble catalysts for various applications.However,the exploration of TMSs-based catalysts for hydrogenation of nitro c...Transition metal sulfides(TMSs)-based materials have been extensively investigated as effective non-noble catalysts for various applications.However,the exploration of TMSs-based catalysts for hydrogenation of nitro compounds is limited.Herein,CoSx/NC catalysts were prepared by solvothermal sulfurization of ZIF-67,followed by high-temperature annealing(300–600℃)under NH3 atmosphere.It was found that the structures and compositions of the as-prepared CoSx/NC can be readily tuned by varying the annealing temperature.Particularly,CoSx/NC-500,which possesses higher degree of S defects and larger specific surface areas,can achieve high conversion,selectivity and stability for catalytic reduction of nitro compounds into amines under mild reaction conditions.展开更多
Various purification methods were explored to eliminate the dissolved hydrogen and nonmetallic inclusions from molten aluminum alloys. A novel rotating impeller head with self-oscillation nozzles or an electromagnetic...Various purification methods were explored to eliminate the dissolved hydrogen and nonmetallic inclusions from molten aluminum alloys. A novel rotating impeller head with self-oscillation nozzles or an electromagnetic valve in the gas circuit was used to produce pulse gas currents for the rotary impeller degassing method. Water simulation results show that the size of gas bubbles can be decreased by 10%20% as compared with the constant gas current mode. By coating ceramic filters or particles with active flux or enamels, composite filters were used to filter the scrap A356 alloy and pure aluminum. Experimental results demonstrate that better filtration efficiency and operation performance can be obtained. Based on numerical calculations, the separation efficiency of inclusions by high frequency magnetic field can be significantly improved by using a hollow cylinder-like separator or utilizing the effects of secondary flow of the melt in a square separator. A multi-stage and multi-media purification platform based on these methods was designed and applied in on-line processing of molten aluminum alloys. Mechanical properties of the processed scrap A356 alloy are greatly improved by the composite purification.展开更多
基金Project(22078368)supported by the National Natural Science Foundation of China。
文摘The utilization of solar energy for hydrogen production via water splitting has garnered considerable attention in the realm of renewable energy.Si nanowires photocathodes own the advantages of effective photon absorption,non toxicity and industrial applicability.Nevertheless,the photoelectrocatalytic(PEC)performance of Si nanowires photocathodes is still limited by ineffective or deficient active sites on their surfaces.Here,we develop an efficient Si based photocathode modified with Al-porphyrin-based MOF(Al-PMOF),consisted of an earth-abundant metal containing Al(OH)O_(4) cluster bridged by 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin.The assembled Al-PMOF significantly enhances the photocurrent density of bare Si nanowires photocathodes,resulting in a twofold increase under equivalent conditions,alongside a positive shift of 200 mV in the onset potential of the Si/Al-PMOF photocathode.The improved PEC hydrogen evolution performance is ascribed to accelerate surface charge transfer of Si photocathode and provision of favorable active site for the hydrogen evolution reaction.This work provides insights into the fabrication of semiconductor/molecule catalyst hybrid photocathodes,thus facilitating the realization of high-efficiency PEC water splitting.
基金supported by National Natural Science Foundation of China(22202093)the Scientific and Technological Innovation Youth Talent Team of Shanxi Province(202204051001005)。
文摘Preparation of highly active hydrodesulfurization catalysts is extremely meaningful for the sulfur removal from thiophene substances.In this work,commercial nano-Al_(2)O_(3)with mesoporous structure supported monometallic phosphide(NiP/Al_(2)O_(3)and MoP/Al_(2)O_(3))and bimetallic phosphide(NiMoP/Al_(2)O_(3)with various Ni/Mo molar ratio)catalysts are successfully prepared by temperature-programmed reduction.X-ray diffraction(XRD)result shows the Ni/Mo molar ratio affect the crystal phase in catalysts.Scanning electron microscopy(SEM),transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS)characterizations co-confirm the interact between Ni and Mo elements in bimetallic phosphide.Catalyst evaluation in hydrodesulfurization of dibenzothiophene shows that bimetallic phosphide samples exhibit better catalytic performance than monometallic phosphide.62.1%conversion and 86.3%biphenyl selectivity with 30 h stability are achieved over NiMoP/Al_(2)O_(3)(Ni/Mo=1∶1)catalyst at 400℃under 3 MPa H_(2).All characterization results demonstrate that the improved activity of bimetallic phosphide owes to the Ni-Mo synergistic effect in NiMoP/Al_(2)O_(3)(Ni/Mo=1∶1)catalyst.This finding provides a guide to the design of bimetallic catalyst with synergistic effect.
基金Project(20574020) supported by the National Natural Science Foundation of ChinaProject(20061001) supported by the Opening Project of the Key Laboratory of Polymer Processing Engineering, Ministry of Education, ChinaProject (20060106-2) supported by Guangdong Key Projects
文摘Metal hydroxides （MAH） consisting of magnesium hydroxide and aluminum hydroxide with a mass ratio of 1：2 were surface-modified by y-diethoxyphosphorous ester propyldiethoxymethylsilane, boric acid and diphenylsilanediol in xylene under dibutyl tin dilaurate catalyst at 140 ℃. Phosphorus, silicon and boron elements covalently bonded to metal hydroxide particles were detected by X-ray photoelectron spectroscopy. The degradation behavior of the surface-modified MAH was characterized by thermogravimetric analysis. The results show that linear low density polyethylene （LLDPE） composite, filled with 50% （mass fraction） of MAH modified by 5.0% （mass fraction） of modifiers, passes the V-0 rating of UL-94 test and shows the limited oxygen index of 34%, and its heat release rate and average effective heat combustion in a cone calorimeter measurement decrease obviously; The mechanical properties of MAH can be improved by surface-modification. The uniform dispersion of particles and strong interfacial bonding between particles and matrix are obtained.
基金Projects(21636010,21878342)supported by the National Natural Science Foundation of ChinaProject(2019JJ50758)supported by the Hunan Provincial Natural Science Foundation of China+1 种基金Project(2019TP1001)supported by the Hunan Provincial Science and Technology Plan Project of ChinaProject(CX20190097)supported by the Fundamental Research Funds for the Central Universities,China。
文摘Transition metal sulfides(TMSs)-based materials have been extensively investigated as effective non-noble catalysts for various applications.However,the exploration of TMSs-based catalysts for hydrogenation of nitro compounds is limited.Herein,CoSx/NC catalysts were prepared by solvothermal sulfurization of ZIF-67,followed by high-temperature annealing(300–600℃)under NH3 atmosphere.It was found that the structures and compositions of the as-prepared CoSx/NC can be readily tuned by varying the annealing temperature.Particularly,CoSx/NC-500,which possesses higher degree of S defects and larger specific surface areas,can achieve high conversion,selectivity and stability for catalytic reduction of nitro compounds into amines under mild reaction conditions.
文摘Various purification methods were explored to eliminate the dissolved hydrogen and nonmetallic inclusions from molten aluminum alloys. A novel rotating impeller head with self-oscillation nozzles or an electromagnetic valve in the gas circuit was used to produce pulse gas currents for the rotary impeller degassing method. Water simulation results show that the size of gas bubbles can be decreased by 10%20% as compared with the constant gas current mode. By coating ceramic filters or particles with active flux or enamels, composite filters were used to filter the scrap A356 alloy and pure aluminum. Experimental results demonstrate that better filtration efficiency and operation performance can be obtained. Based on numerical calculations, the separation efficiency of inclusions by high frequency magnetic field can be significantly improved by using a hollow cylinder-like separator or utilizing the effects of secondary flow of the melt in a square separator. A multi-stage and multi-media purification platform based on these methods was designed and applied in on-line processing of molten aluminum alloys. Mechanical properties of the processed scrap A356 alloy are greatly improved by the composite purification.
