Advances in selective electrochemical methanol upgrading and energy-saving hydrogen production: Mechanism, progress, and prospects

This review explores the viability of selectively upgrading methanol to formate as a potential route for hydrogen production, with a particular emphasis on replacing the anodic oxygen evolution reaction in electrolyzers. Transition metal-based electrocatalysts demonstrate significant potential for selectively upgrading methanol to formate. The review elucidates the challenges associated with noble metal-based electrocatalysts, including catalyst deactivation resulting from carbon monoxide (CO) intermediate adsorption and restricted methanol-to-formate selectivity. Mechanistic insights are delved into, with a focus on electrochemical methanol oxidation pathways such as O–H and C–H activation. The impact of methanol concentration on selectivity is examined, alongside the interaction between methanol oxidation and oxygen evolution. Catalyst composition is scrutinized, highlighting nickel-based and Ni-free materials, while exploring strategies to reduce cell voltage, advanced characterization techniques (e.g., in-situ Raman, X-ray absorption fine structure spectroscopy), nanotechnology advancements, and cost-effective hydrogen production through methanol-assisted water splitting. Additionally, the review underscores the potential of methanol upgrading for hydrogen production, acknowledges existing challenges, and proposes innovative avenues for future research.