MoO4
2−-modulated NiOOH is synthesized and employed as multifunctional electrocatalysts for methanol-assisted direct seawater electrolysis. The MoO4
2− modification enhances the oxygen evolution reaction and proton-coupled electron transfer in the methanol oxidation reaction while simultaneously increasing the energy barrier for the chlorine evolution reaction. This dual effect effectively reduces the energy requirements of seawater splitting and enables stable operation at industrial current densities.
Abstract
Seawater electrolysis holds great promise for sustainable, green hydrogen production but faces challenges of high overpotentials and competing chlorine evolution reaction (CER). Replacing the oxygen evolution reaction with the methanol oxidation reaction (MOR) presents a compelling alternative due to its lower anodic potential which mitigates the risk of CER. While NiOOH is known for its MOR activity, its performance is limited by sluggish non-electrochemical kinetics and Cl-induced degradation. Herein, a MoO4
2−-modified NiOOH electrocatalyst is reported that significantly enhances MOR-assisted seawater splitting efficiency. In situ leached MoO4
2− from the heterojunction optimizes methanol adsorption and facilitates proton migration, thereby accelerating the non-electrochemical steps in MOR. Additionally, the adsorbed MoO4
2− effectively repels Cl−, protecting the electrodes from Cl−-induced corrosion. The MOR-assisted electrolyzer using NiMo||Ni(OH)2/NiMoO₄ requires only 1.312 V to achieve 10 mA cm−2, substantially lower than conventional alkaline seawater electrolysis (1.576 V). Furthermore, it demonstrates remarkable stability, sustaining high current densities (up to 1.0 A cm−2) for over 130 h. This work presents a promising strategy for designing high-performance electrocatalysts for efficient and sustainable green hydrogen production from seawater.
Advanced Science, Volume 12, Issue 14, April 10, 2025. Read More
