Transition Metal Atoms Anchored on Square Graphyne as Multifunctional Electrocatalysts: A Computational Investigation

Abstract

Multifunctional electrocatalysts for hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are vital to develop energy conversion and storage devices. In this work, by means of density functional theory (DFT) computations, we have investigated the HER, OER and ORR catalytic activities of a series of transition atoms (including Sc, Ti, Cr, Mn, Fe, Co, Ni, Cu, Ru, Rh, Pd, Os, Ir and Pt) anchored on square graphyne (TM@S-GPY). Our results revealed that the Ni@S-GPY can act as a promising trifunctional catalyst for HER/OER/ORR with overpotentials of 0.07/0.43/0.36 V, while Pt@S-GPY and Ir@S-GPY can be utilized as eligible bifunctional electrocatalysts for water splitting (HER/OER) with overpotentials of 0.04/0.59 and 0.07/0.36 V, respectively. In addition, Pd@S-GPY exhibits high catalytic activity for OER/ORR with overpotentials of 0.40/0.34 V. Especially, depending on their diverse electronic properties, the catalytic activity of these SACs can be well rationalized by their optimal binding strengths with reaction intermediates. Thus, S-GPY is an ideal support for immobilizing single atom catalysts to design stable and highly-efficient multifunctional catalysts in various electrochemical processes.

Keywords: Density functional theory, Square graphyne, Multifunctional single atom electrocatalysts, Overpotential