Photothermal-promoted anion exchange membrane seawater electrolysis on a nickel-molybdenum-based catalyst

Exploring active, durable catalysts and utilizing external renewable energy sources offer notable opportunities for advancing seawater electrolysis. Here, a multifunctional NiMo-based catalyst (NiMo-H₂) composed of bimetallic Ni_0.91Mo_0.09 nanoparticles on MoO₂ nanorods is demonstrated for the alkaline seawater hydrogen evolution reaction. The alloying effect and the nanorod-nanoparticle structure endow this catalyst with high structural stability, rapid electron transfer, and a large surface area. The in situ-generated alloyed nanoparticles have notable light absorption and photothermal conversion capabilities, while the vertically grown nanorods suppress diffuse reflection, enabling efficient localized photoheating. Consequently, light irradiation boosts the catalyst's activity and it works stably at a current density of 500 mA cm^-2 in alkaline seawater. We then assemble the NiMo-H₂||NiFe LDH pair in a photothermal anion exchange membrane electrolyzer, and it requires approximately 1.6 V to drive a current of 0.45 A, demonstrating robust durability in overall alkaline seawater electrolysis. This photothermal-promoted seawater electrolysis system shows notable potential for hydrogen production from seawater.