降低催化剂中贵金属Pt含量是构建高性能析氢反应(Hydrogen evolution reaction,HER)电催化剂的关键。通过电化学沉积法将Cu纳米修饰到二维Nb_(2)CT_(x)表面,然后利用电化学置换反应制备得到二维Nb_(2)CT_(x)负载Pt纳米颗粒(PtNP/Nb_(2)C...降低催化剂中贵金属Pt含量是构建高性能析氢反应(Hydrogen evolution reaction,HER)电催化剂的关键。通过电化学沉积法将Cu纳米修饰到二维Nb_(2)CT_(x)表面,然后利用电化学置换反应制备得到二维Nb_(2)CT_(x)负载Pt纳米颗粒(PtNP/Nb_(2)CT_(x))催化剂。采用SEM、XRD和XPS等手段对所得催化剂的形貌、结构及组成进行表征,并研究了PtNP/Nb_(2)CT_(x)催化剂在酸性和中性介质中的电催化HER性能。结果表明,在10 m A·cm^(-2)电流密度下,PtNP/Nb_(2)CT_(x)催化剂在0.5 mol·L^(-1)H2SO4和1.0 mol·L^(-1)PBS电解液中的过电压分别为38 m V和146 m V,Tafel斜率分别为42和64 m V·dec^(-1);在0.5 mol·L^(-1)H2SO4中,过电压为50 m V下,催化剂的质量活性和转换频率值分别为36.5 A·mgPt^(-1)和11.5 s^(-1);在1.0 mol·L^(-1)PBS中,过电压为100 m V下,催化剂质量活性和转换频率分别为4.1 A·mgPt^(-1)和4.2 s^(-1),PtNP/Nb_(2)CT_(x)催化剂表现出优异的HER活性。最后在电流密度为10 m A·cm^(-2)下,0.5 mol·L^(-1)H2SO4和1.0 mol·L^(-1)PBS电解液中通过计时电流法进行5 h的稳定性测试,该催化剂均表现出良好的稳定性。该催化剂的成功合成为制备低Pt含量高性能电催化析氢材料提供了新的思路和研究方法。展开更多
Cathode catalysts for direct alcohol fuel cells(DAFCs) must have high catalytic activity for the oxy-gen reduction reaction(ORR), low cost, and high tolerance to the presence of methanol or ethanol. Pt is the benchmar...Cathode catalysts for direct alcohol fuel cells(DAFCs) must have high catalytic activity for the oxy-gen reduction reaction(ORR), low cost, and high tolerance to the presence of methanol or ethanol. Pt is the benchmark catalyst for this application owing to its excellent electrocatalytic activity, but its high cost and low tolerance to the organic fuel permeating through the membrane have hindered the commercialization of DAFCs. Herein we present a facile synthesis route to obtain organic fuel-tolerant Zr- and Ta-based catalysts supported on carbon. This method consists of a simple precipitation of metal precursors followed by a heat treatment. X-ray diffraction analyses confirmed that the obtained samples were crystalline ZrO 2-x and Na2Ta8O21-x having crystallite sizes of 26 and 32 nm, respectively. The thermal treatment effectively increased the activity of the catalysts to-wards the ORR, although further optimization is necessary. Both catalysts exhibited a high tolerance to the presence of methanol with only a moderate reduction in ORR activity even at high methanol concentration(0.5 mol/L).展开更多
文摘降低催化剂中贵金属Pt含量是构建高性能析氢反应(Hydrogen evolution reaction,HER)电催化剂的关键。通过电化学沉积法将Cu纳米修饰到二维Nb_(2)CT_(x)表面,然后利用电化学置换反应制备得到二维Nb_(2)CT_(x)负载Pt纳米颗粒(PtNP/Nb_(2)CT_(x))催化剂。采用SEM、XRD和XPS等手段对所得催化剂的形貌、结构及组成进行表征,并研究了PtNP/Nb_(2)CT_(x)催化剂在酸性和中性介质中的电催化HER性能。结果表明,在10 m A·cm^(-2)电流密度下,PtNP/Nb_(2)CT_(x)催化剂在0.5 mol·L^(-1)H2SO4和1.0 mol·L^(-1)PBS电解液中的过电压分别为38 m V和146 m V,Tafel斜率分别为42和64 m V·dec^(-1);在0.5 mol·L^(-1)H2SO4中,过电压为50 m V下,催化剂的质量活性和转换频率值分别为36.5 A·mgPt^(-1)和11.5 s^(-1);在1.0 mol·L^(-1)PBS中,过电压为100 m V下,催化剂质量活性和转换频率分别为4.1 A·mgPt^(-1)和4.2 s^(-1),PtNP/Nb_(2)CT_(x)催化剂表现出优异的HER活性。最后在电流密度为10 m A·cm^(-2)下,0.5 mol·L^(-1)H2SO4和1.0 mol·L^(-1)PBS电解液中通过计时电流法进行5 h的稳定性测试,该催化剂均表现出良好的稳定性。该催化剂的成功合成为制备低Pt含量高性能电催化析氢材料提供了新的思路和研究方法。
基金the "Mobility project Italy-Canada (Québec) n° QU13MO7"the financial support of the EU through the DURAMET Project 278054+1 种基金funding from the European Community’s Seventh Framework Programme (FP7/2011–2014) for the Fuel Cells and Hydrogen Joint Technology Initiative under grant agreement DURAMET no. 278054""Fonds de Recherche du Québec-Nature et Technologies (FQRNT)" for financial support
文摘Cathode catalysts for direct alcohol fuel cells(DAFCs) must have high catalytic activity for the oxy-gen reduction reaction(ORR), low cost, and high tolerance to the presence of methanol or ethanol. Pt is the benchmark catalyst for this application owing to its excellent electrocatalytic activity, but its high cost and low tolerance to the organic fuel permeating through the membrane have hindered the commercialization of DAFCs. Herein we present a facile synthesis route to obtain organic fuel-tolerant Zr- and Ta-based catalysts supported on carbon. This method consists of a simple precipitation of metal precursors followed by a heat treatment. X-ray diffraction analyses confirmed that the obtained samples were crystalline ZrO 2-x and Na2Ta8O21-x having crystallite sizes of 26 and 32 nm, respectively. The thermal treatment effectively increased the activity of the catalysts to-wards the ORR, although further optimization is necessary. Both catalysts exhibited a high tolerance to the presence of methanol with only a moderate reduction in ORR activity even at high methanol concentration(0.5 mol/L).
