Unraveling the Synergistic Dual-Active-Site and Redox Cycling Mechanisms in CoS@NiCo LDH for Enhanced Methanol Electrooxidation.

Engineering electrocatalysts with tailored electronic structures is essential for achieving efficient methanol oxidation reactions (MOR), yet it remains a significant challenge. This work introduces a CoS@NiCo LDH nanoarray electrocatalyst created through a simple one-step method, exhibiting exceptional activity and durability via synergistic electronic modulation and dual-active-site catalysis.The in situ formed heterointerface between Co3S4 and NiCo LDH facilitates substantial electron redistribution, which significantly enhances charge transfer kinetics and optimizes the adsorption energy of key reaction intermediates. Additionally, in situ spectroscopic studies capture the dynamic redox cycling of Ni2+/Ni3+ and Co2+/Co3+ during MOR, revealing the fundamental mechanisms responsible for the accelerated reaction kinetics. The catalyst demonstrates exceptional performance, requiring only 1.42 V to achieve a current density of 100 mA cm-2, while maintaining approximately 85% selectivity for formate over 41 h of continuous operation. Notably, when it is configured for methanol-assisted water electrolysis, the system produces high-purity hydrogen at a rate of 2608 μL min-1 which is 3.4 times faster than conventional alkaline water electrolysis. This advancement allows for simultaneous production of valuable chemicals and energy-efficient hydrogen generation. This study offers both a mechanistic understanding and a practical design strategy for multifunctional electrocatalysts in integrated energy conversion systems.