Hydrogen evolution reaction(HER)is the major cathodic reaction which competes CO2 reduction reaction(CO2 RR)on Pt electrode.Molecular level understanding on how these two reactions interact with each other and what th...Hydrogen evolution reaction(HER)is the major cathodic reaction which competes CO2 reduction reaction(CO2 RR)on Pt electrode.Molecular level understanding on how these two reactions interact with each other and what the key factors are of CO2 RR kinetics and selectivity will be of great help in optimizing electrolysers for CO2 reduction.In this work,we report our results of hydrogen evolution and CO2 reduction on Pt(111)and Pt film electrodes in CO2 saturated acid solution by cyclic voltammetry and infrared spectroscopy.In solution with pH>2,the major process is HER and the interfacial pH increases abruptly during HER;COad is the only adsorbed intermediate detected in CO2 reduction by infrared spectroscopy;the rate for COad formation increases with the coverage of UPD-H and reaches maximum at the onset potential for HER;the decrease of COad formation under HER is attributed to the available limited sites and the limited residence time for the reduction intermediate(Had),which is necessary for CO2 adsorption and reduction.展开更多
Important effects exist between precious metals and rare earths oxides in three-way catalyst, especially the coordinated effects. These effects were studied by using H2PtCl6, Pt(NH3)2(NO2)2 and Pt(OH)2(C2H5ONH2)2 as P...Important effects exist between precious metals and rare earths oxides in three-way catalyst, especially the coordinated effects. These effects were studied by using H2PtCl6, Pt(NH3)2(NO2)2 and Pt(OH)2(C2H5ONH2)2 as Pt precursors, and the mixed oxide of (Ce-Zr-La-Pr)O as base material to prepare a series of catalysts, and their performances of the catalysts were studied by TPR and CO pulse titration technologies. The results shown that Pt precursors and their solutions pH values influenced the oxygen storage capabilities, the active metal distribution degrees of the catalysts obviously, and every catalyst prepared by different precursors had an optimal pH values. It indicates that the active metals precursors and their solutions acidities have outstanding influences on the catalysts performances for the mutual effects existing between the active metals and the Rare Earth metal oxides, which results from the mate groups of the precursors and the solution acidity.展开更多
The stability of the complexes of four pyridine-like ligands with Cu(ATP)^(2-) was studied and by comparing the stability constants of the ternary complexes[Cu(ATP)L]^(2-) with those of the binary complexes[CuL]^(2+),...The stability of the complexes of four pyridine-like ligands with Cu(ATP)^(2-) was studied and by comparing the stability constants of the ternary complexes[Cu(ATP)L]^(2-) with those of the binary complexes[CuL]^(2+),a stacking interaction between the pyridine ring and the purine ring of ATP is indicated.It is possible to interpret the antitumor mechanism of[Pt(NH_3)_8 (N-het)Cl]Cl in terms of this stacking interaction.展开更多
A detailed study of the cyclic voltammtry curve of Pt(111) electrode in H2SO4 solution by X-ray photoe1ectron spectroscopy (XPS) and a low energy electron diffeaction (LEED) has provided firstly direct evidence that t...A detailed study of the cyclic voltammtry curve of Pt(111) electrode in H2SO4 solution by X-ray photoe1ectron spectroscopy (XPS) and a low energy electron diffeaction (LEED) has provided firstly direct evidence that the anomalous features reported originally by Clavilier et al. are associated with the specific adsorption of sulfate ainons rather than hydrogen adsorption. The ()R30 structure on Pt(111) obtained after electrode emersion on the positive scan at more positive potentials than 0.23V vs. Ag/AgCl appears sedtaneously with sharp increase of XPS of O1s and S2p. This implies the relationship between anomalous peak and sulfate anion adsorption on emersed Pt(111 ) electrode.展开更多
通过溶液中等离子法快速制备Pt纳米颗粒,选用TiO_2(P25)提升Pt纳米颗粒的电催化性能,并以石墨烯纳米片(GNs)为载体材料,通过简单的超声混合制备Pt/GNs/TiO_2催化剂。采用X线衍射仪(XRD)、透射电子显微镜(TEM)、X线光电子能谱仪(XPS)及...通过溶液中等离子法快速制备Pt纳米颗粒,选用TiO_2(P25)提升Pt纳米颗粒的电催化性能,并以石墨烯纳米片(GNs)为载体材料,通过简单的超声混合制备Pt/GNs/TiO_2催化剂。采用X线衍射仪(XRD)、透射电子显微镜(TEM)、X线光电子能谱仪(XPS)及循环伏安曲线(CV)测试等表征手段分析样品的组成、形貌、表面电子特性及对甲醇的电催化性能。结果表明:制备得到了在GNs表面分布均匀、结晶性良好并且直径为2~5 nm的Pt纳米颗粒,同时TiO_2也成功分散在GNs表面。加入TiO_2极大地提高了Pt纳米颗粒对甲醇的电催化活性,Pt/GNs/TiO_2的电流密度约为2 480 m A/mg,是未加入TiO_2的Pt/GNs(747 m A/mg)的3.3倍,同时其循环性能和抗中毒性能也得到了提升。展开更多
基金supported by the National Natural Science Foundation of China (No.21473175 and No.21273215)the Ministry of Science and Technology of China (No.2015CB932301)
文摘Hydrogen evolution reaction(HER)is the major cathodic reaction which competes CO2 reduction reaction(CO2 RR)on Pt electrode.Molecular level understanding on how these two reactions interact with each other and what the key factors are of CO2 RR kinetics and selectivity will be of great help in optimizing electrolysers for CO2 reduction.In this work,we report our results of hydrogen evolution and CO2 reduction on Pt(111)and Pt film electrodes in CO2 saturated acid solution by cyclic voltammetry and infrared spectroscopy.In solution with pH>2,the major process is HER and the interfacial pH increases abruptly during HER;COad is the only adsorbed intermediate detected in CO2 reduction by infrared spectroscopy;the rate for COad formation increases with the coverage of UPD-H and reaches maximum at the onset potential for HER;the decrease of COad formation under HER is attributed to the available limited sites and the limited residence time for the reduction intermediate(Had),which is necessary for CO2 adsorption and reduction.
基金Project supported by the National High Technology Research and Development Programs (863 ) of China (2002 AA321060, 2004AA649040) Yunnan Province Science Technology Program (2004B0028Q)
文摘Important effects exist between precious metals and rare earths oxides in three-way catalyst, especially the coordinated effects. These effects were studied by using H2PtCl6, Pt(NH3)2(NO2)2 and Pt(OH)2(C2H5ONH2)2 as Pt precursors, and the mixed oxide of (Ce-Zr-La-Pr)O as base material to prepare a series of catalysts, and their performances of the catalysts were studied by TPR and CO pulse titration technologies. The results shown that Pt precursors and their solutions pH values influenced the oxygen storage capabilities, the active metal distribution degrees of the catalysts obviously, and every catalyst prepared by different precursors had an optimal pH values. It indicates that the active metals precursors and their solutions acidities have outstanding influences on the catalysts performances for the mutual effects existing between the active metals and the Rare Earth metal oxides, which results from the mate groups of the precursors and the solution acidity.
文摘The stability of the complexes of four pyridine-like ligands with Cu(ATP)^(2-) was studied and by comparing the stability constants of the ternary complexes[Cu(ATP)L]^(2-) with those of the binary complexes[CuL]^(2+),a stacking interaction between the pyridine ring and the purine ring of ATP is indicated.It is possible to interpret the antitumor mechanism of[Pt(NH_3)_8 (N-het)Cl]Cl in terms of this stacking interaction.
文摘A detailed study of the cyclic voltammtry curve of Pt(111) electrode in H2SO4 solution by X-ray photoe1ectron spectroscopy (XPS) and a low energy electron diffeaction (LEED) has provided firstly direct evidence that the anomalous features reported originally by Clavilier et al. are associated with the specific adsorption of sulfate ainons rather than hydrogen adsorption. The ()R30 structure on Pt(111) obtained after electrode emersion on the positive scan at more positive potentials than 0.23V vs. Ag/AgCl appears sedtaneously with sharp increase of XPS of O1s and S2p. This implies the relationship between anomalous peak and sulfate anion adsorption on emersed Pt(111 ) electrode.
文摘通过溶液中等离子法快速制备Pt纳米颗粒,选用TiO_2(P25)提升Pt纳米颗粒的电催化性能,并以石墨烯纳米片(GNs)为载体材料,通过简单的超声混合制备Pt/GNs/TiO_2催化剂。采用X线衍射仪(XRD)、透射电子显微镜(TEM)、X线光电子能谱仪(XPS)及循环伏安曲线(CV)测试等表征手段分析样品的组成、形貌、表面电子特性及对甲醇的电催化性能。结果表明:制备得到了在GNs表面分布均匀、结晶性良好并且直径为2~5 nm的Pt纳米颗粒,同时TiO_2也成功分散在GNs表面。加入TiO_2极大地提高了Pt纳米颗粒对甲醇的电催化活性,Pt/GNs/TiO_2的电流密度约为2 480 m A/mg,是未加入TiO_2的Pt/GNs(747 m A/mg)的3.3倍,同时其循环性能和抗中毒性能也得到了提升。
