This study explores the adsorption and reac-tion of methanol on the CeO_(2)(111)and Ni/CeO_(2)(111)surfaces,highlighting the es-sential role of metal-support interaction in methanol decomposition by a synergistic ap-p...This study explores the adsorption and reac-tion of methanol on the CeO_(2)(111)and Ni/CeO_(2)(111)surfaces,highlighting the es-sential role of metal-support interaction in methanol decomposition by a synergistic ap-proach encompassing synchrotron radiation photoemission spectroscopy,X-ray photo-electron spectroscopy,infrared reflection and absorption spectroscopy,and temperature-programmed desorption.Our findings reveal that Ni deposited on the CeO_(2)(111)surface,followed by annealing to 700 K,leads to the formation of Ce-O-Ni mixed oxide as the dominant phase.The Ni^(2+)species facilitate the methoxy decomposition into CO and H_(2)within 300-430 K,with a small amount of formalde-hyde also forming at the edge sites of ceria.Additionally,some methoxy adsorbed on the bare CeO_(2)surface migrates to the Ce-O-Ni mixed oxide,where they decompose into CO and H_(2)at 500-600 K,accompanied by a portion of the methoxy interacting with ceria to generate formaldehyde.Upon exposure to methanol at 500 K,the Ni^(2+)species are reduced to metallic Ni^(0),alongside the formation of coke and Ni_(3)C,ultimately resulting in catalyst deactivation.However,reintroducing O_(2)reactivates these sites by oxidizing metallic Ni^(0)and Ni_(3)C species.This study highlights the pivotal role of metal-support interaction in promoting oxygen trans-fer from ceria to Ni,thereby enhancing methoxy decomposition and significantly improving the performance of Ni-based catalysts for methanol decomposition into CO and H_(2).展开更多
Hairong Wang, Yaoqiang Chen, Qiulin Zhang, Qingchao Zhu, Maochu Gong, Ming Zhao（ Key Laboratory of Green Chemistry ＆ Technology of Ministry Education, College of Chemistry, Sichuan University, Chengdu 610064, Sichua...Hairong Wang, Yaoqiang Chen, Qiulin Zhang, Qingchao Zhu, Maochu Gong, Ming Zhao（ Key Laboratory of Green Chemistry ＆ Technology of Ministry Education, College of Chemistry, Sichuan University, Chengdu 610064, Sichuan, China展开更多
The catalytic behaviors of Pd （1.4 wt.%） catalysts supported on CeO2-ZrO2 promoted with La2O3 were investigated for methanol decomposition. The measurements of inductively coupled plasma emission spectroscopy （ICP...The catalytic behaviors of Pd （1.4 wt.%） catalysts supported on CeO2-ZrO2 promoted with La2O3 were investigated for methanol decomposition. The measurements of inductively coupled plasma emission spectroscopy （ICP）, N2 adsorption-desorption （BET）, powder X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, temperature-programmed reduction （TPR） and oxygen storage capacity （OSC） were used to characterize the properties of catalysts. The catalysts＇ activities were tested in a fixed bed continuous flow reactor operating under atmospheric pressure. The Pd/Ce0.8Zr0.2O2-5 wt.%La2O3 catalyst exhibited the best activity. The reasons for this were twofold： （1） doping of La improved effectively textural properties of CeO2-ZrO2 oxygen storage materials, and （2） Pd/Ce0.8Zr0.2O2-5 wt.%La2O3 possessed super oxygen storage property and reducibility due to the existence of lattice defect oxygen or mobile oxygen, which helped to re-oxidize zerovalent Pd0 to a partly oxidized Pdδ＋. By introducing 5 wt.%La2O3, the specific surface area of the sample increased, but declined if further increasing the content of La2O3 to 10 wt.%.展开更多
Pd/Ce0.8Zro.202 catalysts modified by cobalt were prepared by a sequential impregnation method and characterized by X-ray powder diffraction （XRD）, N2 adsorption/desorption （Brunauer-Emmet-Teller）, oxygen storage ...Pd/Ce0.8Zro.202 catalysts modified by cobalt were prepared by a sequential impregnation method and characterized by X-ray powder diffraction （XRD）, N2 adsorption/desorption （Brunauer-Emmet-Teller）, oxygen storage capacity （OSC）, CO-chemisorption, H2-temperature-programmed reduction （H2-TPR） and X-ray photoelectron spectroscopy （XPS）. The effect of Co on the performance of methanol decomposition was eval- uated at a fixed-bed microreactor. The results showed that the addition of Co can improve the oxygen storage capacity of the catalyst and the dispersion of Pd. XPS results indicated that Pd was in a partly oxidized （Pd6＋, 1〈8〈2） state and Co2＋ was present in Pd catalysts modified by Co. A 90% conversion of methanol was achieved at around 280 ℃ over Pd-Co/Ceo.8Zro.202 catalyst which was 20 ℃ lower than that over Pd/Ceo.sZro.202, indicating that both pd6＋and Co2＋ play an important role in improving the catalytic activity of methanol decomposition.展开更多
Mesoporous TiO2-CeO2 mixed oxide(m-TiO2-CeO2) were synthesized using n-cetylpyridinium chloride (C16PyCl) as a structure-directing agent under the neutral conditions and room temperature. The synthesized mesoporous sa...Mesoporous TiO2-CeO2 mixed oxide(m-TiO2-CeO2) were synthesized using n-cetylpyridinium chloride (C16PyCl) as a structure-directing agent under the neutral conditions and room temperature. The synthesized mesoporous samples were characterized by FT-IR, XRD, and N2 adsorption BET methods. The incorporation of Ce3+ ions into the channel wall improves the stability of the mesoporous structure obviously. After ruthenium being loaded by the impregnating method, the Ru particle strongly interacts with the mesoporous mixed supports. Although a part of the particles are possible to block the support pores, the catalytic activity of ruthenium supported on the m-TiO2-CeO2 for methanol decomposition to carbon monoxide and hydrogen is significantly higher than that of ruthenium supported on m-TiO2. A synergistic effect between CeO2 and TiO2 was observed for promoting the catalytic properties of Ru.展开更多
The photocatalytic decomposition of methanol in the presence of vanadium dichloride and the transfer of hydrogen and methyl free radicals to the additives and dinitrogen were reported.
From the chemical catalysis viewpoint,the excellent performance of CNTs in adsorption-activation of H2 and in promoting spillover of adsorbed H-species is very attractive,in addition to their nanosize channels,sp2-C c...From the chemical catalysis viewpoint,the excellent performance of CNTs in adsorption-activation of H2 and in promoting spillover of adsorbed H-species is very attractive,in addition to their nanosize channels,sp2-C constructed surfaces,and high thermal/electrical conductivity.This review examines some recent progresses of CNTs as a novel support or promoter of catalysts for certain hydrogenation or dehydrogenation reactions,e.g.,hydrogenation-conversion of syngas to yield alcohols and decomposition or steam-reforming of methanol to generate H2,mainly based on recent work carried out in our laboratory.展开更多
基金financially supported by the National Key R&D Program of China(2023YFA1509103)the National Natural Science Foundation of China(Nos.22272157,21872131,22106085,and U1932214)。
文摘This study explores the adsorption and reac-tion of methanol on the CeO_(2)(111)and Ni/CeO_(2)(111)surfaces,highlighting the es-sential role of metal-support interaction in methanol decomposition by a synergistic ap-proach encompassing synchrotron radiation photoemission spectroscopy,X-ray photo-electron spectroscopy,infrared reflection and absorption spectroscopy,and temperature-programmed desorption.Our findings reveal that Ni deposited on the CeO_(2)(111)surface,followed by annealing to 700 K,leads to the formation of Ce-O-Ni mixed oxide as the dominant phase.The Ni^(2+)species facilitate the methoxy decomposition into CO and H_(2)within 300-430 K,with a small amount of formalde-hyde also forming at the edge sites of ceria.Additionally,some methoxy adsorbed on the bare CeO_(2)surface migrates to the Ce-O-Ni mixed oxide,where they decompose into CO and H_(2)at 500-600 K,accompanied by a portion of the methoxy interacting with ceria to generate formaldehyde.Upon exposure to methanol at 500 K,the Ni^(2+)species are reduced to metallic Ni^(0),alongside the formation of coke and Ni_(3)C,ultimately resulting in catalyst deactivation.However,reintroducing O_(2)reactivates these sites by oxidizing metallic Ni^(0)and Ni_(3)C species.This study highlights the pivotal role of metal-support interaction in promoting oxygen trans-fer from ceria to Ni,thereby enhancing methoxy decomposition and significantly improving the performance of Ni-based catalysts for methanol decomposition into CO and H_(2).
基金the National Natural Science Foundation of China (20773090)the Specialized Research Fund for the Doctoral Program of Higher Education of China (20070610026, 200806100009)
文摘Hairong Wang, Yaoqiang Chen, Qiulin Zhang, Qingchao Zhu, Maochu Gong, Ming Zhao（ Key Laboratory of Green Chemistry ＆ Technology of Ministry Education, College of Chemistry, Sichuan University, Chengdu 610064, Sichuan, China
基金Project supported by the Programs Foundation of Ministry of Education of China (20070610026)the National Natural Science Foundation of China (20773090, 20803049)
文摘The catalytic behaviors of Pd （1.4 wt.%） catalysts supported on CeO2-ZrO2 promoted with La2O3 were investigated for methanol decomposition. The measurements of inductively coupled plasma emission spectroscopy （ICP）, N2 adsorption-desorption （BET）, powder X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, temperature-programmed reduction （TPR） and oxygen storage capacity （OSC） were used to characterize the properties of catalysts. The catalysts＇ activities were tested in a fixed bed continuous flow reactor operating under atmospheric pressure. The Pd/Ce0.8Zr0.2O2-5 wt.%La2O3 catalyst exhibited the best activity. The reasons for this were twofold： （1） doping of La improved effectively textural properties of CeO2-ZrO2 oxygen storage materials, and （2） Pd/Ce0.8Zr0.2O2-5 wt.%La2O3 possessed super oxygen storage property and reducibility due to the existence of lattice defect oxygen or mobile oxygen, which helped to re-oxidize zerovalent Pd0 to a partly oxidized Pdδ＋. By introducing 5 wt.%La2O3, the specific surface area of the sample increased, but declined if further increasing the content of La2O3 to 10 wt.%.
基金supported by the National Natural Science Foundation of China(No.21173153)Sichuan Province Science and Technology Support Projects(2012FZ0008)
文摘Pd/Ce0.8Zro.202 catalysts modified by cobalt were prepared by a sequential impregnation method and characterized by X-ray powder diffraction （XRD）, N2 adsorption/desorption （Brunauer-Emmet-Teller）, oxygen storage capacity （OSC）, CO-chemisorption, H2-temperature-programmed reduction （H2-TPR） and X-ray photoelectron spectroscopy （XPS）. The effect of Co on the performance of methanol decomposition was eval- uated at a fixed-bed microreactor. The results showed that the addition of Co can improve the oxygen storage capacity of the catalyst and the dispersion of Pd. XPS results indicated that Pd was in a partly oxidized （Pd6＋, 1〈8〈2） state and Co2＋ was present in Pd catalysts modified by Co. A 90% conversion of methanol was achieved at around 280 ℃ over Pd-Co/Ceo.8Zro.202 catalyst which was 20 ℃ lower than that over Pd/Ceo.sZro.202, indicating that both pd6＋and Co2＋ play an important role in improving the catalytic activity of methanol decomposition.
文摘Mesoporous TiO2-CeO2 mixed oxide(m-TiO2-CeO2) were synthesized using n-cetylpyridinium chloride (C16PyCl) as a structure-directing agent under the neutral conditions and room temperature. The synthesized mesoporous samples were characterized by FT-IR, XRD, and N2 adsorption BET methods. The incorporation of Ce3+ ions into the channel wall improves the stability of the mesoporous structure obviously. After ruthenium being loaded by the impregnating method, the Ru particle strongly interacts with the mesoporous mixed supports. Although a part of the particles are possible to block the support pores, the catalytic activity of ruthenium supported on the m-TiO2-CeO2 for methanol decomposition to carbon monoxide and hydrogen is significantly higher than that of ruthenium supported on m-TiO2. A synergistic effect between CeO2 and TiO2 was observed for promoting the catalytic properties of Ru.
文摘The photocatalytic decomposition of methanol in the presence of vanadium dichloride and the transfer of hydrogen and methyl free radicals to the additives and dinitrogen were reported.
基金supported by the National Basic Research Program of China(2011CBA00508)the National Natural Science Foundation of China(20923004)the Program for Changjiang Scholars and Innovative Research Team in University(IRT1036)
文摘From the chemical catalysis viewpoint,the excellent performance of CNTs in adsorption-activation of H2 and in promoting spillover of adsorbed H-species is very attractive,in addition to their nanosize channels,sp2-C constructed surfaces,and high thermal/electrical conductivity.This review examines some recent progresses of CNTs as a novel support or promoter of catalysts for certain hydrogenation or dehydrogenation reactions,e.g.,hydrogenation-conversion of syngas to yield alcohols and decomposition or steam-reforming of methanol to generate H2,mainly based on recent work carried out in our laboratory.
