Electron-transfer enhancement of urchin-like CoP–Ce2(CO3)2O/NF as an ultra-stable bifunctional catalyst for efficient overall water splitting

Abstract

Effective control of strong electron interaction at heterogeneous interfaces is crucial for the creation of highly efficient and stable bifunctional catalysts for water splitting. In this work, we synthesized an urchin-like CoP–Ce₂(CO₃)₂O catalyst on nickel foam (CoP–Ce₂(CO₃)₂O/NF) via a facile hydrothermal and gas-phase phosphating process, which enhances active site exposure and improves catalytic reaction kinetics. Spectroscopy analysis reveals that the enhanced performance is due to the charge transfer between CoP and Ce₂(CO₃)₂O and the unique urchin-like structure of the hybrid catalyst. The CoP–Ce₂(CO₃)₂O/NF catalyst showed excellent hydrogen/oxygen evolution reaction (HER/OER) performance (η₁₀ = 85.2 and 205.5 mV) and robust long-term stability in 1.0 M KOH. Additionally, the CoP–Ce₂(CO₃)₂O/NF⁽⁺⁾||CoP–Ce₂(CO₃)₂O/NF⁽⁻⁾ electrolyzer required only a low cell voltage of 1.82 V to produce 100 mA cm⁻² for overall water splitting, outperforming most previous catalysts. This work presents a strategy for interfacial engineering to improve the activity of bifunctional heterojunction electrocatalysts for overall water splitting.