Work function induced electron rearrangement of Ru@Ir core-shell nanocatalysts for promoting pH-universal overall water splitting

Abstract

Water splitting, one of the primary strategies for advancing the utilization of hydrogen production, necessitates the input of external energies to initiate the reaction due to its thermodynamically uphill nature. Nevertheless, Ru-based compounds, which were widely used as benchmark anodic catalysts, facing significant drawbacks such as their susceptibility to dissolution, significantly restrict the overall water splitting efficiency. In this work, we introduce an approach for functionalization through combining Ru nanospheres with Ir to form a Ru@Ir core–shell structure (denoted as Ru@Ir core–shell NSs), which can activate the superior oxygen evolution reaction (OER) catalytic activity, and simultaneously inherit the hydrogen evolution reaction (HER) performance in all-pH condition. The work function difference between Ru and Ir promotes the necessary energetic impetus for electron migration from Ru to Ir, resulting in the charge redistribution. Density functional theory (DFT) calculations confirmed that the Ir shell, acting as an electron acceptor, could effectively trigger electron rearrangement, augmenting the ligand affinity of hydrogen and oxygen intermediates to attain the most favorable energy states, thereby accelerating the kinetics of hydrogen and oxygen evolution. Our suggested core–shell structure approach for manipulating interface charge distribution might find utility in creating other electrocatalysts for water splitting.