Tuning interface density and electronic structure of NiS/Ni3S4 by Mo, Co co-doping for efficient urea electrooxidation reaction

Abstract

Mo, Co co-doped NiS/Ni 3 S 4 with high activity, low onset potential, fast kinetics, more active sites, excellent intrinsic catalytic activity and stability demonstrates excellent catalytic activity toward alkaline urea electrolysis. • Mo, Co co-doped NiS/Ni 3 S 4 heterojunction with 3D flower-like shape assembled by 2D ultrathin nanosheets are successfully prepared. • The amount of heterointerfaces and the electronic interaction are simultaneously modified by adjusting experimental parameters. • Mo, Co co-doped NiS/Ni 3 S 4 catalysts exhibit rich exposed active sites and facilitated electron transportation. • The assembled direct urea hydrogen peroxide fuel cell (DUHPFC) employing Mo 0.05 ,Co-NSH has an open-circle voltage (OCV) of 0.86 V and a maximum power density ( P max ) of 5.96 mW cm −2 . Electrocatalysts exhibiting impressive catalytic capability and strong stability for urea oxidation reaction (UOR) are highly desired for direct urea fuel cells (DUFCs). Herein, a series of flower-like Mo, Co co-doped NiS/Ni 3 S 4 heterostructure (Mo, Co-NSH) are controllable synthesized by a one-step hydrothermal method and utilized as catalysts for UOR. Taking advantages of massive heterojunctions, tunable electronic configuration and hierarchical flower-like topological structure together, the optimized component demonstrates advanced UOR performance compared to pure NiS/Ni 3 S 4 and mono Co/Mo element doped NiS/Ni 3 S 4 , it delivers 147.1 mA cm −2 at 1.6 V vs. RHE and works for more than 18 h without decay. The assembly direct urea hydrogen peroxide fuel cell (DUHPFC) with Mo 0.05 , Co-NSH catalyst has an open-circuit voltage of 0.86 V and a maximum power density of 5.96 mW cm −2 at 27 °C. The work provides a promising avenue for exploiting efficient electrocatalysts on both multi-metal doping and heterojunction engineering for electrochemical energy conversion and sewage treatment applications.