High-frequency ultrasound modulates the interfacial Ni(OH)2/NiOOH redox transition to enhance glucose electrooxidation and hydrogen production

Replacing the kinetically limited oxygen evolution reaction with biomass electrooxidation offers a promising route toward energy-efficient hydrogen production, yet the electrooxidation reaction’s performance remains hindered by interfacial kinetics and catalyst accessibility. Here, we demonstrate that high-frequency ultrasound acts as a dynamic physical field that drives interfacial chemical activation, enabling enhanced glucose electrooxidation on nickel foam under mild conditions. Under acoustic irradiation, the Ni(OH) 2 /NiOOH redox transition undergoes a substantial cathodic shift of approximately 450 mV, leading to an earlier onset of glucose electrooxidation and a significant increase in anodic current density. A qualitative comparison with low-frequency ultrasound (20 kHz), performed as a hydrodynamic benchmark, showed no corresponding shift in onset potential, highlighting an interfacial activation mechanism specific to HFUS rather than a general hydrodynamic effect. As a result, glucose electrooxidation currents increase by up to fourfold at steady state, accompanied by a twofold sustained enhancement in cathodic hydrogen production. We propose that acoustic cavitation dynamically perturbs the electrode–electrolyte interface, increasing electrochemical accessibility and facilitating OH – adsorption. This accelerates the formation and turnover of NiOOH active sites while mitigating surface deactivation. These findings establish acoustic cavitation as a versatile physical lever to enhance interfacial charge-transfer kinetics in transition-metal-mediated biomass electroreforming, offering a strategy complementary to traditional catalyst design and opening new directions for biomass electrooxidation and hydrogen production.