A sulfided Mo/γ-Al2O3 catalyst was characterized by low-temperature FTIR spectroscopy of adsorbed carbon monoxide, with its HDS activity being investigated with thiophene as a mold substrate. On the basis of the resu...A sulfided Mo/γ-Al2O3 catalyst was characterized by low-temperature FTIR spectroscopy of adsorbed carbon monoxide, with its HDS activity being investigated with thiophene as a mold substrate. On the basis of the results here, the conclusion may be obtained that the sites for CO adsorption should be the active reaction centers of thiophene HDS.展开更多
A series of sulfided tertiary NiMoP/ γ Al 2O 3 catalysts with different contents of MoO 3 were prepared by using molybdophosphoric acid of Keggin structure(H 3PMo 12 O 40 ) and nickel nitrate as origins of active pha...A series of sulfided tertiary NiMoP/ γ Al 2O 3 catalysts with different contents of MoO 3 were prepared by using molybdophosphoric acid of Keggin structure(H 3PMo 12 O 40 ) and nickel nitrate as origins of active phase components of molybdenum, phosphorus and nickel, and characterized by TPR technique, with their HDS activity being investigated with thiophene as a model substrate. For the sulfided Mo 0 catalyst containing no nickel as promoter, the only hydrogen sulfide evolution peak Ⅰ is observed at 462 K and attributed to the hydrogenation of the so called edge sulfur atoms chemisorbed on coordinatively unsaturated(cus) Mo x+ sites on the MoS 2 phase(MoS 2 slab). With the introduction of nickel into the active phase of the sulfided Mo 0 catalyst and with the increase of the molybdenum loading, a new hydrogen sulfide evolution peak Ⅱ gradually develops at the low temperature side of the peak Ⅰ, at the same time accompanied by both the increase of the area ratio of the peak Ⅱ to the peak Ⅰ and the shift of the hydrogen sulfide evolution maximum rate to lower temperatures, which may imply the existence of two kinds of active centers related to molybdenum and nickel respectively and the synergic action between the two centers above. It should be noted that for the sulfided NiMoP/ γ Al 2O 3 catalysts, the thiophene HDS rate and the quantity of hydrogen sulfide evolved during TPR process increase monotonously with the atomic ratio of molybdenum to nickel in the form of [ n (Ni)+ n (Mo)]/ n (Ni). On the basis of the results here, the conclusion may be reached that the two kinds of vacancies can be formed on the edge of Ni Mo S slab due to the loss of S during TPR process and vacancies or sites related to the H 2S evolution peak II should be regarded as the mainly active reaction centers of thiophene HDS.展开更多
A series of sulfided PtMo/ γ Al 2O 3 catalysts[ w (Mo)=9.0%] with different contents of Pt were characterized by using low temperature FTIR spectroscopy of adsorbed CO, while their HDS activity was investigated with ...A series of sulfided PtMo/ γ Al 2O 3 catalysts[ w (Mo)=9.0%] with different contents of Pt were characterized by using low temperature FTIR spectroscopy of adsorbed CO, while their HDS activity was investigated with thiophene as a model substrate. Experimentally, it was found that no existence of the bands related to the surface complexes of Al 3+ ←CO and Pt 0←CO→Pt 0 was observed at 77 K and that the rate of the thiophene HDS reaction(573 K) is well linearly proportional to the area of the Pt 0←CO band at 2 093 cm -1 with a higher extrapolated HDS rate compared to that of sulfided Mo/ γ Al 2O 3 catalyst at the zero content of platinum. On the basis of the results here, the conclusion may be made that the active monolayer phase of Pt Mo S may be formed over sulfided PtMo/ γ Al 2O 3 catalysts during the sulfidation process and that both Mo 2+ and Pt 0 sites for CO adsorption should be the active reaction centers of thiophene HDS.展开更多
A new type of non-soluble copper aluminophosphate（denoted as CuAlPO） was synthesized by（static） hydrothermal crystallization and characterized by using several physicochemical techniques.XRD analysis reveals that ...A new type of non-soluble copper aluminophosphate（denoted as CuAlPO） was synthesized by（static） hydrothermal crystallization and characterized by using several physicochemical techniques.XRD analysis reveals that CuAlPO can be obtained from a reactive gel of molar composition: iso-Pr2NH∶0.3CuO∶（0.7Al2O3∶）P2O5∶80H2O in a Teflon-lined stainless steel autoclave at 180 ℃ for 72 h and has the same crystal structure as that of hexagonal SiO2（JCPDS No.83-2299）.The sources of CuO,Al2O3 and P2O5 were copper sulfate pentahydrate,aluminum isopropoxide and o-phosphoric acid（mass fraction: 85%）,respectively.SEM shows a characteristic hexagonal morphology and a crystallite size of about 2 μm for both the as-synthesized CuAlPO and the calcined CuAlPO（550 ℃,6h）.Low specific surace area（2.0 m2/g） and pore volume（0.004 mL/g） of CuAlPO were observed by N2-adsorption measurement.Catalytic evaluation tests demonstrate that an excellent transformation of phenol into catechol and hydroquinone over the material was achieved in water under the benign reaction conditions with a phenol conversion of 29.5% being observed at room temperature（30 ℃）.展开更多
文摘A sulfided Mo/γ-Al2O3 catalyst was characterized by low-temperature FTIR spectroscopy of adsorbed carbon monoxide, with its HDS activity being investigated with thiophene as a mold substrate. On the basis of the results here, the conclusion may be obtained that the sites for CO adsorption should be the active reaction centers of thiophene HDS.
文摘A series of sulfided tertiary NiMoP/ γ Al 2O 3 catalysts with different contents of MoO 3 were prepared by using molybdophosphoric acid of Keggin structure(H 3PMo 12 O 40 ) and nickel nitrate as origins of active phase components of molybdenum, phosphorus and nickel, and characterized by TPR technique, with their HDS activity being investigated with thiophene as a model substrate. For the sulfided Mo 0 catalyst containing no nickel as promoter, the only hydrogen sulfide evolution peak Ⅰ is observed at 462 K and attributed to the hydrogenation of the so called edge sulfur atoms chemisorbed on coordinatively unsaturated(cus) Mo x+ sites on the MoS 2 phase(MoS 2 slab). With the introduction of nickel into the active phase of the sulfided Mo 0 catalyst and with the increase of the molybdenum loading, a new hydrogen sulfide evolution peak Ⅱ gradually develops at the low temperature side of the peak Ⅰ, at the same time accompanied by both the increase of the area ratio of the peak Ⅱ to the peak Ⅰ and the shift of the hydrogen sulfide evolution maximum rate to lower temperatures, which may imply the existence of two kinds of active centers related to molybdenum and nickel respectively and the synergic action between the two centers above. It should be noted that for the sulfided NiMoP/ γ Al 2O 3 catalysts, the thiophene HDS rate and the quantity of hydrogen sulfide evolved during TPR process increase monotonously with the atomic ratio of molybdenum to nickel in the form of [ n (Ni)+ n (Mo)]/ n (Ni). On the basis of the results here, the conclusion may be reached that the two kinds of vacancies can be formed on the edge of Ni Mo S slab due to the loss of S during TPR process and vacancies or sites related to the H 2S evolution peak II should be regarded as the mainly active reaction centers of thiophene HDS.
文摘A series of sulfided PtMo/ γ Al 2O 3 catalysts[ w (Mo)=9.0%] with different contents of Pt were characterized by using low temperature FTIR spectroscopy of adsorbed CO, while their HDS activity was investigated with thiophene as a model substrate. Experimentally, it was found that no existence of the bands related to the surface complexes of Al 3+ ←CO and Pt 0←CO→Pt 0 was observed at 77 K and that the rate of the thiophene HDS reaction(573 K) is well linearly proportional to the area of the Pt 0←CO band at 2 093 cm -1 with a higher extrapolated HDS rate compared to that of sulfided Mo/ γ Al 2O 3 catalyst at the zero content of platinum. On the basis of the results here, the conclusion may be made that the active monolayer phase of Pt Mo S may be formed over sulfided PtMo/ γ Al 2O 3 catalysts during the sulfidation process and that both Mo 2+ and Pt 0 sites for CO adsorption should be the active reaction centers of thiophene HDS.
文摘A new type of non-soluble copper aluminophosphate（denoted as CuAlPO） was synthesized by（static） hydrothermal crystallization and characterized by using several physicochemical techniques.XRD analysis reveals that CuAlPO can be obtained from a reactive gel of molar composition: iso-Pr2NH∶0.3CuO∶（0.7Al2O3∶）P2O5∶80H2O in a Teflon-lined stainless steel autoclave at 180 ℃ for 72 h and has the same crystal structure as that of hexagonal SiO2（JCPDS No.83-2299）.The sources of CuO,Al2O3 and P2O5 were copper sulfate pentahydrate,aluminum isopropoxide and o-phosphoric acid（mass fraction: 85%）,respectively.SEM shows a characteristic hexagonal morphology and a crystallite size of about 2 μm for both the as-synthesized CuAlPO and the calcined CuAlPO（550 ℃,6h）.Low specific surace area（2.0 m2/g） and pore volume（0.004 mL/g） of CuAlPO were observed by N2-adsorption measurement.Catalytic evaluation tests demonstrate that an excellent transformation of phenol into catechol and hydroquinone over the material was achieved in water under the benign reaction conditions with a phenol conversion of 29.5% being observed at room temperature（30 ℃）.
