In-Situ Reconstruction-Regulated Fe-Doped Ni(OH)2 for Glucose Oxidation Electrocatalytic-Enhanced Seawater Electrolysis

Abstract

Coupling glucose oxidation electrocatalytic (GOR) with seawater electrolysis enables high-efficiency, low-energy-consumption H₂ production while co-producing high-value chemicals. Herein, nickel foam-supported Fe-doped Ni(OH)₂ catalysts (Fe_xNi(OH)₂@NF) were synthesized by hydrothermal method for GOR-assisted seawater electrolysis. Operando electrochemical impedance spectroscopy and in situ Raman spectroscopy reveal that Fe doping lowers the potential for in-situ reconstruction into NiOOH active species, and markedly boosts the catalytic activities for GOR. Specifically, Fe_0.15Ni(OH)₂@NF achieves 100 mA cm^-2 at only 1.38 V (vs. reversible hydrogen electrode, RHE), 210 mV lower than that for OER, greatly reducing energy consumption. An anion exchange membrane (AEM) flow electrolyzer using Fe_0.15Ni(OH)₂@NF as both anode and cathode maintains high stability after 10 consecutive cycles (∼250 h total operation). This system delivers excellent Faradaic efficiencies (FEs), with anode FEs of 73.9 ± 2.2% and 24.7 ± 1.6% for formate and gluconate, respectively, and a cathode H₂ evolution FE as high as 99.2 ± 0.5%. This study provides new insights into designing high-efficiency, low-cost catalysts for biomass-coupled seawater electrolysis, facilitating the industrialization of this sustainable H₂ production technology.