Hydrogen spillover effect enhanced Cu2O/Cu/Mn2O3 catalyst for dual-electrode electrocatalytic hydrogen evolution

Abstract

Replacing the oxygen evolution reaction (OER) with the anodic formaldehyde oxidation reaction (FOR) is crucial for achieving low-voltage dual-electrode hydrogen evolution. However, existing FOR catalysts face challenges such as low activity, high transition state barriers, and unclear reaction mechanisms. In this study, a three-dimensional nano-composite Cu₂O/Cu/Mn₂O₃ heterogeneous catalyst with enhanced hydrogen spillover effect was synthesized through hydrothermal and photosensitive oxidation treatment techniques. The catalyst consists of ∼20 nm Cu₂O/Cu and 30–70 nm Mn₂O₃ nanoparticles. The hydrogen spillover effect enhanced Cu₂O/Cu/Mn₂O₃ (1:1) electrocatalyst demonstrated outstanding FOR performance, with an anode potential of only 0.128 V at a current density of 100 mA cm⁻², significantly lower than that of the Cu₂O/Cu-CC catalyst (0.25 V) and the OER potential (1.726 V). Moreover, the Faraday efficiency of the Cu₂O/Cu/Mn₂O₃ (1:1) electrocatalyst reached ∼100%. The electrocatalyst’s FOR performance remains stable over 50 h without decay, and its hydrogen evolution reaction (HER) performance surpasses that of Cu and MnO_x electrocatalysts. Density functional theory (DFT) calculations suggested that the Cu₂O/Cu/Mn₂O₃ catalyst significantly lowers the energy barriers for C–H bond breaking (0.48 eV) and H–H bond formation (−0.99 eV) by promoting the hydrogen spillover effect. This study provides theoretical support for designing efficient and stable low-energy dual-electrode hydrogen evolution catalysts and validates their potential through experiments.