Novel Ru‐O<sub>3</sub>Se<sub>4</sub> Single Atoms Regulate the Charge Redistribution at Ni<sub>3</sub>Se<sub>2</sub>/FeSe<sub>2</sub> Interface for Improved Overall Water Splitting in Alkaline Media
Linke Guo, Tianpeng Liu, Le Zhang, Mengyao Ma, Peng Gao, Dong Cao, Daojian Cheng
Abstract
Abstract Developing low‐cost, highly active, and stable bifunctional catalysts is of great significance for electrochemical water splitting. Herein, novel Ru‐O 3 Se 4 single atoms doped Ni 3 Se 2 /FeSe 2 interface catalyst is fabricated by a two‐step method for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Notably, Ru‐Ni 3 Se 2 /FeSe 2 nanosheets exhibit excellent HER (43 mV@10 mA cm −2 ) and OER (283 mV@100 mA cm −2 ) activities in alkaline solution. In particular, the mass activity of Ru‐Ni 3 Se 2 /FeSe 2 catalyst is 3593.61 mA mg Ru −1 at 200 mV for HER and 7073.80 mA mg Ru −1 at 400 mV for OER, which is 25.91 and 367.28 times of commercial Pt/C and RuO 2 , respectively. In situ spectroscopy techniques confirm Ru‐O 3 Se 4 single atoms facilitate the adsorption of intermediates H * and OOH * during HER and OER processes, respectively. Further density functional theory calculations reveal introducing Ru‐O 3 Se 4 single atoms causes the transfer of electrons from Ru to Ni and Fe atoms, leading to a redistribution of charge at the Ni 3 Se 2 /FeSe 2 interface, thus reducing the energy barriers of rate‐determining step to −0.37 and 1.92 eV for HER and OER, respectively. This work emphasizes the significant role of single atoms at the interface for overall water splitting.