应用于氧还原反应的非贵金属原子分散级金属-氮-碳催化剂的设计

为了进一步实现质子交换膜燃料电池(PEMFC)能量转化技术的大规模开发和应用, 提高催化剂的成本效益是先决条件. 目前, 与铂族等贵金属基催化剂相比, 原子分散的金属-氮-碳(M-N-C)催化剂也在提高活性位点密度、 原子利用率和催化活性等方面表现出巨大的潜力, 是最有望代替铂基催化剂的首选材料. 在原子分散M-N-C催化剂的制备过程中, 获得活性位点均匀分散且结构体系最优化是挑战性问题. 基于此, 我们重点研究了各种有利于原子分散的M-N-C催化剂的制备方法, 以及不同催化剂中原子的化学环境调控对催化位点的影响. 本文从M-N-C催化剂的合成与表征、 反应机理、 密度泛函理论计算等方面进行了深入的探讨, 着重讨论了双金属位点、 原子簇结构和杂原子对催化位点的化学环境调控. 最后, 提出了原子分散M-N-C催化剂大规模应用存在的问题及进一步优化的发展方向.

Atomically Dispersed Metal-Nitrogen-Carbon Catalysts for Oxygen Reduction Reaction

To further accelerate the large-scale development and application of proton exchange membrane fuel cell（PEMFC） energy conversion technology， improving the cost-effectiveness of the catalyst is a prerequisite. Currently， atomically dispersed metal-nitrogen-carbon（M-N-C） catalysts also take tremendous potential in terms of increased active site density， atomic utilization and catalytic activity compared to noble metal-based catalysts such as platinum-based catalysts， and are the most promising candidate of platinum-based catalysts. During the preparation of atomically dispersed M-N-C catalysts， the contribution of the uniform dispersion and the optimal structural system of all active sites are the challenge issues. On this basis， we focused on the preparation of various M-N-C catalysts with favorable atomic dispersion and the effect of chemical environment modulation of atoms in different catalysts on the catalytic sites. Herein， we provide an in-depth discussion on the synthesis and characterization of M-N-C catalysts， reaction mechanism， and density functional theory calculations， focusing on the regulation of the chemical environment of catalytic sites by bimetallic sites， atomic cluster structure and heteroatoms. Finally， the problems of the large-scale application of atomically dispersed M-N-C catalysts and the development directions for further optimization are presented.