Deprotonation-Accelerated Interstitial Si-doped RuO2 with Brønsted Sites for Enhanced Acidic OER

Abstract

Hydrogen production via proton exchange membrane water electrolysis (PEMWE) is a promising route for high-purity hydrogen. While iridium is commonly used at the anode, its high cost and limited activity drive interest in Ru-based alternatives. However, Ru catalysts face slow OER kinetics and poor acidic stability due to sluggish proton-transfer. Here, we report a Ru-based catalyst (RSW) doped with W and interstitial Si via a sol-gel method. The optimized RSW catalyst achieves an overpotential of 170 mV at 10 mA cm-2 in 0.5 M H2SO4 and excellent durability with only 62.7 mV/h degradation over 600 hours. In a PEMWE device, it operates stably at 100 mA cm-2 for 100 h. W creates Brønsted acid sites for fast deprotonation, while Si inhibits Ru overoxidation via electron donation and shortens Ru- O-W bonds, enhancing proton transport. This modulation accelerates deportation and shifts the OER mechanism from adsorbate evolution mechanism (AEM) to a favorable oxide path mechanism (OPM) pathway. This work provides a strategy combining proton-transfer engineering and electronic tuning for efficient, acid-stable OER catalysts.