Pt基合金氧还原催化剂设计的密度泛函理论计算研究

Abstract

本文提出以合金形成能、Pt表面偏析能和氧原子吸附能作为依据筛选具有高活性和高稳定性的表面富Pt氧还原合金催化剂. 利用DFT计算对Pt与各种过渡金属形成的合金的热力学、表面化学和电子性质进行了系统研究，在此基础上预测Pt-V，Pt-Fe，Pt-Co，Pt-Ni，Pt-Cu，Pt-Zn，Pt-Mo，Pt-W等合金可能具有好的氧还原催化活性和稳定性. 所预期的大部分催化剂已有文献研究结果支持. 另外，Pt-Zn和Pt-Mo体系目前报道尚不多，值得进一步的细致研究.

Developing Pt-lean catalysts for oxygen reduction reaction (ORR) is the key for large-scale application of proton exchange membrane fuel cell (PEMFC). In this paper, we have proposed a multiple-descriptor strategy for screening efficient and durable ORR alloy catalysts of low Pt content. We argue that an ideal Pt-based bimetallic alloy catalyst for ORR should possess simultaneously negative alloy formation energy, negative surface segregation energy of Pt and a lower oxygen binding ability than pure Pt. By performing detailed DFT calculations on the thermodynamics, surface chemistry and electronic properties of various Pt-M alloys (M refers to non-precious transition metals in the periodic table), Pt-V，Pt-Fe，Pt-Co，Pt-Ni，Pt-Cu，Pt-Zn，Pt-Mo，Pt-W are predicted to have improved catalytic activity and durability for ORR, most of which have indeed been reported to have excellent ORR catalytic performance in the literature. It is suggested that the ORR performance of Pt-Zn and Pt-Mo systems deserve detailed theoretical and experimental investigations.