纳米氧化铈对铂表面二氧化硫吸附/氧化的促进作用及其机理研究

Proton exchange membrane fuel cell (PEMFC) has many advantages such as low or even zero pollution, high efficiency, high power density, wide source of renewable hydrogen. It’s of great importance to improve the tolerance towards sulfur dioxide and the stability of platinum based catalysts. The key issue is to find out the sulfur dioxide electro-adsorption/oxidation mechanism on platinum surface and the related impacts. It is fundamental to vary platinum electronic structure or sulfur dioxide electro-adsorption state and decrease the binding energy of sulfur dioxide on platinum surface for enhancing the sulfur dioxide tolerance of platinum catalyst. We propose to support platinum nanoparticles on ceria nanocrystals, preparing the catalysts with enhanced sulfur dioxide tolerance. The interaction between platinum and ceria may take great effect on promoting the sulfur dioxide electro-oxidation. The effect of ceria structure on the sulfur dioxide electro-adsorption/oxidation on platinum surface, including the influence of lattice oxygen on sulfur dioxide electro-adsorption states and electro-oxidation paths will be studied by both experimental and computational methods. It is expected to reveal the relationship between structure and activity towards sulfur dioxide electro-adsorption/oxidation of catalysts.

以氢气作为燃料的质子交换膜燃料电池，因低污染甚至零污染、高效率、高功率密度、氢气来源广泛且可再生等优点显示出广泛的应用前景，近年来备受推崇。改善铂催化剂对二氧化硫的抗中毒性能，提高铂催化剂稳定性对于质子交换膜燃料电池未来发展具有重要的意义。认识二氧化硫在铂表面的吸附/氧化机理及其影响规律是改善催化剂稳定性必须解决的关键科学问题。要提高铂的抗二氧化硫中毒性能，须调变铂的电子结构或二氧化硫的吸附转态，以减弱二氧化硫分子与铂的结合力，降低二氧化硫的氧化电位。申请者拟用氧化铈作为载体，在其上负载铂纳米粒子，利用两者的相互作用，预计可以获得对二氧化硫的电化学氧化能力增强的电极材料。在这个基础上，结合实验分析与理论计算，系统研究纳米氧化铈对铂表面上二氧化硫吸附以及氧化过程的影响，包括氧化铈的晶格氧对改变二氧化硫吸附状态以及氧化路径的机理研究，有望揭示其构效关系，获得突破。

以氢气作为燃料的质子交换膜燃料电池，因低污染甚至零污染、高效率、高功率密度、氢气来源广泛且可再生等优点显示出广泛的应用前景，近年来备受推崇。改善铂催化剂对二氧化硫的抗中毒性能，提高铂催化剂稳定性对于质子交换膜燃料电池未来发展具有重要的意义。认识二氧化硫在铂表面的吸附/氧化机理及其影响规律是改善催化剂稳定性必须解决的关键科学问题。本项目制备了氧化铈与铂纳米粒子的催化剂，获得了对二氧化硫的电化学氧化能力增强的效果；系统研究纳米氧化铈对铂表面上二氧化硫吸附以及氧化过程的影响。研究显示，要提高铂的抗二氧化硫中毒性能，须调变铂的电子结构或二氧化硫的吸附转态，以减弱二氧化硫分子与铂的结合力，降低二氧化硫的氧化电位。