Rationally Constructed Triple Interfaces in Rh/Cu₃P/MnP Heterostructured Electrocatalysts for Enhanced Overall Water Splitting

Rationally designed electrocatalysts with excellent catalytic activity and robust stability are essential for enhancing the performance of water splitting toward a near-future hydrogen economy. In this work, we report a highly efficient triphase hetero-interface heterostructured electrocatalyst consisting of ultrafine Rh nanoparticles anchored on Cu3P/MnP nanosheets supported on Ni foam (labelled Rh/Cu3P/MnP) to boost the performance of overall water splitting. Experiments clarify the impressive role of the triphase hetero-interface of Rh, Cu3P, and MnP in interfacial electronic redistribution, which is significant for optimizing the catalyst's ability to adsorb and desorb reaction intermediates, thereby accelerating electrochemical reaction kinetics. Additionally, the rationally controlled multi-dimensional structure-comprising 0D Rh nanoparticles, 2D Cu3P/MnP nanosheets, and a 3D Ni substrate-endows the catalyst with a large electrochemically active surface area, excellent charge transfer ability, and abundant accessible active species. Therefore, the Rh/Cu3P/MnP catalyst demonstrates promising catalytic performance for the two key reactions in water splitting: the hydrogen evolution reaction and the oxygen evolution reaction. Moreover, a water electrolyzer utilizing Rh/Cu3P/MnP catalytic electrodes exhibits remarkable efficiency and remains stable over 50 h of continuous operation.