Electronic Structure Modulation in High-Entropy@CuxSy Heterostructured Nanorods via Interface Engineering for Enhanced Multifunctional Electrocatalysis.

Developing efficient electrocatalysts capable of concurrently promoting the methanol oxidation reaction (MOR) and the hydrogen evolution reaction (HER) represents a promising route toward sustainable hydrogen generation coupled with value-added chemical production. However, single-phase catalysts struggle to optimize the adsorption/desorption energy barriers of multiple reaction intermediates, leading to sluggish kinetics and limited durability. In this work, high-entropy@copper sulfide (HE@CuxSy) heterojunction nanorods with strong interfacial electronic interactions were successfully constructed through a simple two-step synthesis strategy. By the preferential sulfidation of Cu species, a rich heterogeneous interface was formed, effectively regulating the electronic structure of the material and enhancing the adsorption capacity for methanol and OH-. The optimized HE@CuxSy-40 delivers excellent HER (overpotential: 302 mV@500 mA cm-2) and MOR (potential: 1.268 V@200 mA cm-2) activities, along with exceptional stability over 120 h. In the MOR∥HER coupled electrolysis system, it requires only 1.52 V to achieve 100 mA cm-2 with a Faradaic efficiency of 96% for formate. This study effectively resolved the chemical contradiction between the excessive adsorption of high-entropy materials and the insufficient activity of single-phase copper sulfide through interface engineering, providing a new idea for the design of efficient and stable multifunctional electrocatalysts.