Efficient hydrogen production via urea electrolysis with cobalt doped nickel hydroxide-riched hybrid films: Cobalt doping effect and mechanism aspect

Publication date: January 2020Source: Journal of Catalysis, Volume 381Author(s): C.B. Sun, M.W. Guo, S.S. Siwal, Q.B. ZhangAbstractThe exploration of earth-abundant catalysts that are highly active and robustly stable for urea electrooxidation is critical for energy-efficient hydrogen production associated with urea-rich wastewater purification. Herein, Co-doped α-Ni(OH)2 hybrid films with unique ultrafine nanoparticles assembled network structure are constructed as efficient bifunctional electrocatalysts for urea-assisted water electrolysis. By employing a facile potentiodynamic deposition route carried out in a deep eutectic solvent (Ethaline), ultrafine Ni-based nanoparticles with a α-Ni(OH)2 rich surface doping by Co are in-situ grown on Cu foam substrate (Cox-Ni(OH)2 NPs/CF), creating an integrated electrode full of intimate contact interfaces. The doping of Co triggers a structural transition with electronic structure changes at the electrode surface and lowers the onset potential required for Ni(OH)2/NiOOH, which strongly enhances the urea electrolysis activity. Through potential conditioning procedure, the optimized Co0.26-Ni(OH)2 NPs/CF catalyst (with a Ni/Co proportion of 1:0.26) manifests excellent electrocatalytic performance for urea electrolysis in 1.0 M KOH with 0.5 M urea, presenting a low onset potential of 1.27 V vs. RHE for urea oxidation and an overpotential of 106 mV for the hydrogen evolution reaction at 10 mA cm−2. Impressively, the constructe...
Source: Journal of Catalysis - Category: Chemistry Source Type: research