Recent advances in Substrate Engineering of Platinum Single atom Catalysts for the Electrochemical Oxygen Reduction Reaction

Abstract

The electrochemical reduction of oxygen molecules using platinum single-atom catalysts (Pt-SACs) is a promising approach for creating an efficient and cost-effective oxygen reduction reaction (ORR) in devices for electrochemical energy conversion, storage, and power chemical production. The performance of Pt-SACs in ORR is largely influenced by the substrate on which the Pt atoms are dispersed, as these materials are vital for stabilising the single Pt atoms and adjusting their electronic properties. Thus, carefully choosing support materials such as metal carbides/oxides, porous carbon structures, defected carbon structures, and 3d metal and non-metal (such as N, S, etc.) doped carbon frameworks allows for precise control over the interaction between metal atoms and the substrate, altering the density of states of Pt atoms for effective ORR. Modifying the electronic properties through substrate interactions enhances the OH adsorption energy and lowers the water decomposition energy barriers, thereby boosting the intrinsic activity of Pt-SACs. This review examines various synthesis strategies for Pt-SACs supported on both metal and non-metal-based substrates for ORR, highlighting how substrates can influence the catalytic activity of Pt-SACs. The loading of Pt metal atoms on the substrate is crucial for determining the electrochemical reduction pathways of oxygen molecules. The review concludes by discussing the future outlook for Pt-SACs, focusing on aspects such as scalability, increasing Pt atom loading, innovative substrate design strategies, and mechanistic understanding of ORR on Pt-SACs using in situ techniques. This underscores the importance of substrate engineering in maximising Pt atom utilisation, durability, and selectivity towards ORR, making Pt-SACs ideal for applications in electrochemical energy conversion, storage, and fine chemical production devices.