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
Pt/graphite catalyst was prepared by incipient wetness impregnation using H2PtCl6·6H2O as precursor. The catalyst was characterized by SEM, XRD, XPS and its degradation ability for oxalic acid was evaluated. The ...Pt/graphite catalyst was prepared by incipient wetness impregnation using H2PtCl6·6H2O as precursor. The catalyst was characterized by SEM, XRD, XPS and its degradation ability for oxalic acid was evaluated. The preparation parameters, including the reduction temperature, Pt loading and pyrolysis were studied. The optimal preparation conditions were 350 ℃ with Pt loading of 1.0%. Results show that the loading of Pt can significantly enhance catalytic activity of graphite and that Pt/graphite catalytic ozonation can effectively remove oxalic acid in aqueous solution. The BET surface area of graphite is much smaller than that of activated carbon, however, the catalytic activity of Pt/graphite towards oxalic acid degradation is higher than that of Pt/AC. The XPS results indicate that the active phase at catalyst surface is in the form of Pt0. Compared with that of reduction process in hydrogen, the activity of Pt/graphite catalyst decreases when it is prepared by pyrolysis in air due to the lower Pt dispersion on graphite surface.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。
文摘Pt/graphite catalyst was prepared by incipient wetness impregnation using H2PtCl6·6H2O as precursor. The catalyst was characterized by SEM, XRD, XPS and its degradation ability for oxalic acid was evaluated. The preparation parameters, including the reduction temperature, Pt loading and pyrolysis were studied. The optimal preparation conditions were 350 ℃ with Pt loading of 1.0%. Results show that the loading of Pt can significantly enhance catalytic activity of graphite and that Pt/graphite catalytic ozonation can effectively remove oxalic acid in aqueous solution. The BET surface area of graphite is much smaller than that of activated carbon, however, the catalytic activity of Pt/graphite towards oxalic acid degradation is higher than that of Pt/AC. The XPS results indicate that the active phase at catalyst surface is in the form of Pt0. Compared with that of reduction process in hydrogen, the activity of Pt/graphite catalyst decreases when it is prepared by pyrolysis in air due to the lower Pt dispersion on graphite surface.
