Improved Methanol-to-Formate Electrocatalytic Reaction by Engineering of Nickel Hydroxide and Iron Oxyhydroxide Heterostructures

Article Improved Methanol-to-Formate Electrocatalytic Reaction by Engineering of Nickel Hydroxide and Iron Oxyhydroxide Heterostructures Ning Jian 1,2, Huan Ge 1,2, Yi Ma 1,2, Yong Zhang 1,2, Luming Li 1,2, Junfeng Liu 3, Jing Yu 4, Canhuang Li 4, and Junshan Li 1,2,* 1 School of Mechanic Engineering, Chengdu University, Chengdu 610106, China 2 Institute for Advanced Study, Chengdu University, Chengdu 610106, China 3 Institute for Energy Research, Jiangsu University, Jiangsu 212013, China 4 Catalonia Institute for Energy Research-IREC, Sant Adrià de Besòs, Barcelona 08930, Spain * Correspondence: lijunshan@cdu.edu.cn Received: 8 March 2025; Revised: 21 March 2025; Accepted: 25 March 2025; Published: 27 March 2025 Abstract: Electrocatalytic methanol oxidation reaction (MOR) holds significant value in the chemical industry, as it enables the treatment of methanol-containing wastewater and promotes hydrogen production from water. This study investigates a strategy based on tuning-composition of metal elements to optimize MOR performance, aiming to outperform the current cost-effective and efficient catalysts. To this end, nickel hydroxide and iron oxyhydroxide heterostructures were synthesized through a facile hydrothermal routine, and the catalytic performance of three different Ni/Fe ratios in MOR was examined in alkaline media. Among them, the material with equal Ni/Fe ratio exhibited the best catalytic activity, maintaining a high current density of ~66 mA cm−2 at 1.5 V vs. RHE in 1 M KOH electrolyte with 1 M methanol. Moreover, this developed electrode showed a Faradaic efficiency (FE) of 98.5% for formate production within a continuous 12 h test. Furthermore, density function theory (DFT) calculation was applied to unravel the methanol-to-formate conversion mechanism that was enhanced by the proper Ni/Fe ratio. These results demonstrate the high efficiency and selectivity of efficient methanol-to-formate conversion on NiFe-based materials, providing a promising a non-precious catalyst for electrocatalytic upgrading methanol to value-added formate.