A dual-defective electrocatalyst for methanol oxidation reaction coupled seawater splitting.

Seawater electrolysis is considered a sustainable green hydrogen production route, but it is limited by high energy consumption, corrosion, and the competing chlorine evolution reaction (ClER). This study replaces oxygen evolution reaction (OER) with a low-potential methanol oxidation reaction (MOR) to reduce energy consumption and suppress ClER. We constructed a boron (B)-doped Cu/Mn bimetallic metal-organic framwork (MOF)-derived electrocatalyst (B-CuMn-TPA) on nickel foam, in which dual-defect regulation was achieved through Mn incorporation and B-defect introduction via NaBH4 reduction. This catalyst exhibits excellent performance, achieving 100 and 500 mA cm-2 at 1.34 and 1.41 V (vs. RHE), respectively, with Faradaic efficiency(FE) approaching 100%, and stably outputting 100 mA cm-2 for over 108 h at 1.57 V in MOR-assisted natural seawater electrolysis. The mechanism indicates that Cu/Mn co-coordination and boron doping induce lattice strain and defect enrichment, optimizing the electronic structure. Furthermore, the catalyst gradually transforms into defect-rich layered hydrogen hydroxide (LDH) and forms a heterogeneous interface during the reaction, further promoting charge transfer and intermediate adsorption. This strategy provides a new approach for efficient seawater electrolysis to produce hydrogen.