Tip effect-driven interfacial microenvironment engineering enables highly efficient overall water splitting on Ru...

Alkaline water electrolysis is recognized as an environmentally sustainable approach for generating high-energy-density clean hydrogen. However, its efficiency remains largely limited by the sluggish kinetics water dissociation in the hydrogen evolution reaction (HER), the challenge of activating water molecules, and the excessive consumption of OH^- and high adsorption energy barriers of oxygenated intermediates during the oxygen evolution reaction (OER). In this work, A nanoneedle-structured Ru-NiCo₂O₄-Se electrocatalyst was developed, demonstrating excellent bifunctional electrocatalytic performance for both HER and OER. Through a combination of experimental characterizations and theoretical simulations, it had been revealed that the sharp-tip nanoneedle morphology generates intense local electric fields. These fields facilitate the enrichment of K⁺ ions at the cathode, optimized the interfacial water structure, and substantially lower the energy barrier required for water dissociation. At the anode, the tip effect facilitated OH^- accumulation, enhanced reactant mass transport, and accelerated OER kinetics. Moreover, metal-support interactions (MSI) between Ru nanoclusters and the support effectively modulate the adsorption behavior of H* and oxygenated intermediates, further boosting catalytic performance. The catalyst achieves overpotentials as low as -48 mV for HER and + 231 mV for OER at a current density of 10 mA·cm^-2, and delivers a high overall water splitting current of 100 mA·cm^-2 at a cell voltage of only 1.7 V, along with remarkable long-term durability over hundreds of hours. This study presents an innovative strategy based on interfacial microenvironment engineering and electronic structure modulation, paving a fresh pathway for the development of cost-effective, high-performance, and long-lasting bifunctional electrocatalysts tailored for clean energy conversion.