Integrating Geometric and Electronic Engineering in MoS ₂ @CoS ₂ /MXene: A Tri‐Component Catalyst for Enhanced Hydrogen Evolution Reaction

ABSTRACT Eliminating the hydrogen evolution reaction (HER) performance gap between earth‐abundant non‐noble metal catalysts and noble metal catalysts demands a fundamental shift from simple compositional modification to the complex coordination of hierarchical morphology and interfacial electronic interaction. Herein, we reported the hierarchical structure of a tri‐component electrocatalyst, MoS 2 @CoS 2 /MXene, achieved by vertically anchoring MoS 2 nanosheets onto a CoS 2 framework to maximize edge exposure, followed by electrostatic self‐assembly with conductive Ti 3 C 2 T x MXene. The CoS 2 core functions as an electron donor that activates the exposed edge sites. Additionally, MXene serves as a conductive substrate, successfully preventing aggregation and guaranteeing substantial mechanical stability. As a result, the hybrid catalyst achieves 10 mA cm −2 at 166.3 mV in acidic media, a Tafel slope of 65.6 mV dec −1 and maintaining performance for over 200 h. Significantly, we employed high‐resolution scanning electrochemical microscopy to identify the local catalytic activity. This provided direct, spatially resolved evidence of the interfacial electron transfer and the enhanced activities at specific active sites, validating the structure‐activity relationship at the microscopic level. This study demonstrates an approach in which morphological engineering and interfacial electrical manipulation are combined to offer a novel strategy for improving the efficacy of non‐noble metal catalysts.