Co(OH)2 Nanosheets Array Doped by Cu2+ Ions with Optimal Electronic Structure for Urea-Assisted Electrolytic Hydrogen Generation

Urea electrolysis supplies a great potential in energy-saving hydrogen generation accompanied by simultaneous urea-containing wastewater remediation. Herein, the Co(OH)(2) nanosheets arrays doped by different amount of Cu2+ ions were prepared via a one-step solution-phase method for urea-assisted electrolytic hydrogen generation. The Cu integration can regulate electronic structure, activate Co active sites at low potential, and optimize the charge transfer properties and adsorption states of the catalyst. Moreover, the partially distorted cobalt surroundings caused by Cu dopant in the catalyst is conductive to favor the adsorption of urea and water molecules to the active sites. The optimal Cu-6.2%-Co(OH)(2) nanosheets array exhibited superior urea oxidation reaction (UOR) and hydrogen evolution reaction (HER) performances. Assembling an overall urea electrolyzer using two Cu-6.2%-Co(OH)(2) electrodes gave rise to very small voltages of 1.389 V for 10 mA cm(-2) and 1.781 V for a high current density of 500 mA cm(-2) with remarkable operational stability. The Cu2+ ions doping strategy can be extended to a series of Ni-based compounds with adjustable electronic structures for boosting the activities of UOR and HER.

Automated summary

The incorporation of Cu2+ ions in Co(OH)(2) catalyst improves its electronic structure, activates active sites, and enhances performance in urea-assisted electrolytic hydrogen generation. This doping strategy can be extended to Ni-based compounds to boost the activities of urea oxidation and hydrogen evolution reactions.