Tailoring of Active Sites from Single to Dual Atom Sites for Highly Efficient Electrocatalysis

Abstract

Single atom catalysts (SACs) have been attracting extensive attention in electrocatalysis because of their unusual structure and extreme atom utilization, but the low metal loading and unified single site induced scaling relations may limit their activity and practical application. Tailoring of active sites at the atomic level is a sensible approach to break the existing limits in SACs. In this review, SACs were first discussed regarding carbon or non-carbon supports. Then, five tailoring strategies were elaborated toward improving the electrocatalytic activity of SACs, namely strain engineering, spin-state tuning engineering, axial functionalization engineering, ligand engineering, and porosity engineering, so as to optimize the electronic state of active sites, tune d orbitals of transition metals, adjust adsorption strength of intermediates, enhance electron transfer, and elevate mass transport efficiency. Afterward, from the angle of inducing electron redistribution and optimizing the adsorption nature of active centers, the synergistic effect from adjacent atoms and recent advances in tailoring strategies on active sites with binuclear configuration which include simple, homonuclear, and heteronuclear dual atom catalysts (DACs) were summarized. Finally, a summary and some perspectives for achieving efficient and sustainable electrocatalysis were presented based on tailoring strategies, design of active sites, and in situ characterization.

Writing Excellent Review Articles

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Asymmetric Coordination Environment Engineering of Atomic Catalysts for CO2 Reduction

“…So far, many impressive review papers have summarized the synthesis, characterization, and catalytic performance of SACs [ 51 , 52 , 53 ]. However, methods for breaking the symmetry of metal-N 4 sites, and the unique electronic structure and CO 2 RR catalytic behavior of asymmetric atom sites, are rarely summarized [ 54 , 55 ].…”

Double-Atom Catalysts Featuring Inverse Sandwich Structure for CO2 Reduction Reaction: A Synergetic First-Principles and Machine Learning Investigation

“…Single/double atom catalysts (SACs/DACs) supported on such 2D materials not only can boost electrocatalytic performance but also can maximize metal utilization. − These catalysts have been studied for various important reactions such as carbon monoxide oxidation, hydrogen evolution reaction, oxygen reduction reaction, nitrogen reduction reaction, and CO 2 RR. − Apart from SACs, the DACs loaded on graphene have garnered significant attention both theoretically and experimentally . Notably, introducing a second TM atom in the form of DACs can induce synergistic interactions between metal atoms, thereby triggering enhanced catalyst performance. ,, For example, theoretical studies by Li and co-workers indicated that three DACs (Cu/Mn, Ni/Mn, and Ni/Fe) supported on nitrogen-doped graphene exhibit good CO 2 reduction activity, breaking the original linear relationship between the adsorption strength of COOH* and CO* species . Ren et al successfully synthesized a DAC with Ni/Fe sites anchored on N-doped graphene (Ni/Fe–N 6 –C), where the resulting catalyst achieved an outstanding catalytic efficiency, selectivity, and persistence for CO 2 RR, while their theoretical studies revealed that the synergy between the neighboring Ni/Fe centers accounts for the superior catalytic performance …”