Theoretical insights into heterogeneous single-atom Fe1 catalysts supported by graphene-based substrates for water splitting

Abstract

Single-atom Fe1 catalyst supported by graphene-based substrates (Fe/GS) has the potential to replace noble-metal catalysts in water splitting reaction due to its high activity, high selectivity, and low cost. Here we have constructed four kinds of Fe/GS to probe its application in water splitting reaction. The adsorption characteristics of the water molecule and the reaction path of water splitting on single atom Fe1 catalysts with four types of graphene-based substrates were studied systematically by using the density functional theory (DFT) method. PDOS results show that the 3d orbitals of Fe single atom and 2p orbitals of O atom are highly hybridized and overlapped which are responsible for the strong chemisorption of H2O molecules on Fe/GS surface. Depending on the reaction pathway analysis, the water splitting reaction performs a catalytic activity trend of Fe/DV-GN, Fe/SV-N3, Fe/SV-GN, Fe/DV-N4. While strong metal–support interactions (SMSI) play a key role in the process of water splitting reaction. Furthermore, the reaction kinetics of water splitting was investigated based on transition state theory. This study aims to develop a highly efficient single-atom Fe1 catalyst for water splitting.