Defect-promoted nanoparticles−nanorod Ni−NiMoO4 heterogeneous nanostructures as efficient electrocatalysts to overall water/urea splitting in fresh/sea water

The heterogeneous nanoparticles−nanorod Ni−NiMoO4 nanostructures grown in situ on nickel foam (Ni−NiMoO4/NF) were rationally engineered as efficient electrocatalysts. The morphological and compositional features cooperatively propel high-performance electrocatalysis to hydrogen evolution reaction (η10, η100, and η200 values are 26/84/113 mV in fresh water and 27/101/132 mV in seawater), urea oxidation reaction (η10, η100, and η200 values are 1.321/1.340/1.356 and 1.329/1.344/1.361 V in fresh/seawater). The Ni−NiMoO4/NF nanostructures therefore perform a low cell voltage of 1.506/1.509@10 mA cm−2 in fresh/sea water. Specifically, the record cell voltage even drops to as low as 1.339/1.361 V in fresh/sea water for overall urea splitting (OUS) reaction with a long-term stability for 240 h@100 mA cm−2 toward OUS in seawater. More importantly, to realize a green manner, we also evaluated a solar-driven H2 production. Even in seawater, H2 gas was collected in high speed under solar illumination on a commercial solar panel.