Internal Electric Field Engineered High-Entropy Alloy on Octahedral N-Doped Carbon via Electronegativity Gradient: Synergistic Interfaces Accelerating Hydrogen Evolution and Triiodide/Copper Reduction Reactions

Abstract

The precise electronic regulation of active sites in carbon-based high-entropy alloys (HEAs) represents a crucial approach to enhancing their electrocatalytic activity but remains challenging. This study proposes a 1,3,5-benzenetricarboxylic acid (BTC)-assisted synthesis approach to obtain the in situ growth of a 0D FeCrCoCuMn HEA on 3D octahedral nitrogen-doped carbon (NC). The difference in electronegativity between the metallic elements in the HEA induces electron transfer from Mn to Cu/Co, thereby optimizing the electronic structure of the HEA. Meanwhile, electrons along the HEA-NC interface continuously migrate from the HEA to the NC, leading to a large charge transfer and an internal electric field. Benefiting from the improved electronic structure of the HEA and the synergistic enhancement across the HEA-NC interface, the HEA-NC catalyst achieves an overpotential of 99 mV and a Tafel slope of 64 mV dec−1 toward the hydrogen evolution reaction. With solar cells, the assembled photovoltaic devices achieved power conversion efficiencies of 8.52% and 5.82% in the triiodide reduction and copper reduction reactions, respectively. This work not only demonstrates the electron migration mechanism of the HEA but also establishes a versatile strategy for designing efficient bifunctional catalysts