原子尺度钴基氮碳催化剂对析氧反应的构效关系的研究

Structure-Activity Relationship of Atomic-Scale Cobalt-Based N-C Catalysts in the Oxygen Evolution Reaction

理解析氧反应(OER)电催化剂活性位点的活性来源是开发高效电催化剂的关键。然而,由于催化剂结构-活性关系的复杂性,发展高效电催化剂仍然是一个至关重要的挑战。本文设计了不同Co-N-C催化剂构型,包括单原子、双原子和团簇,并通过第一性原理计算建立了析氧反应构效关系。结果表明,Co-N4由于金属中心的高配位数和与所有析氧反应中间体的适中吸附能,表现出最佳反应性,过电位为0.37V。双原子和团簇的活性来源于催化剂自身与反应中间体相结合的高度配位结构。此外,本文基于Co-N4构型讨论了影响OER活性的其他因素,其中弱金属-金属相互作用可以通过调节Co-O的反键能级优化含氧中间体的吸附降低反应过电位。随后,根据建立的结构-吸附-活性关系,对火山图进行外推,得到CoNi-type4体系OER的过电位为0.23V。本文研究揭示了Co-N-C催化剂OER活性的起源,建立了基于原子尺度的Co-N-C催化剂的构效关系,有助于理解M-N-C基催化剂的高性能,并促进高效OER催化剂的设计。

Understanding the origin of the active site activity in the oxygen evolution reaction(OER)electrocatalysts is key for developing efficient electrocatalysts.However,crucial challenges remain due to the complexity of catalyst structure-activity relationships.Herein,various Co-N-C configurations,including single atoms,diatoms,and clusters,were designed to establish structure-activity relationships by first-principles calculations.It was revealed that the Co-N4exhibited the best reactivity due to the high coordination number of the metal center and moderate adsorption energies for all reaction intermediates.The diatom and cluster activities originate from the highly coordinated structures formed with reaction intermediates,which serve as coordination ligands.Furthermore,other factors influencing the OER activity based on the Co-N4configuration are discussed.For example,the weak metal-metal interaction can further optimize the adsorption of oxygen-containing intermediates by tuning antibonding energy levels of Co-O.Subsequently,an ultralow overpotential of 0.23 V for the OER in Co Ni-type4 systems can be obtained by extrapolation of the volcano plot derived from the established structure-adsorption-activity relationships.This work uncovers the underlying OER activity mechanisms of Co-N-C catalysts,which helps to further understanding of high-performance of M-N-C base catalysts and will aid in the future design of high-efficiency OER catalysts.