Electron modulation of cobalt carbonate hydroxide by Mo doping for urea-assisted hydrogen production

Combining urea oxidation reaction (UOR) with hydrogen evolution reaction (HER) is an effective method for energy saving and highly efficient electrocatalytic hydrogen production . Herein, molybdenum-incorporated cobalt carbonate hydroxide nanoarrays (Co x Mo y CH) are designed and synthesized as a bifunctional catalyst towards UOR and HER . Benefiting from the Mo doping, the dispersed nanoarray structure and redistributed electron density, the Co x Mo y CH catalyst display outstanding catalytic performance and durability for both HER and UOR, affording the overpotential of 82 mV for HER and delivering a low potential of the 1.33 V for UOR (vs. reversible hydrogen electrode, RHE) to attain a current density of 10 mA cm − 2 , respectively. Remarkably, when Co x Mo y CH was applied as bifunctional catalyst in a two-electrode electrolyzer, a working voltage of 1.40 V is needed in urea-assisted water electrolysis at 10 mA cm −2 and without apparent decline for 40 h, outperforming the working voltage of 1.51 V in conventional water electrolysis.