Construction of CeO2/Co(OH)2/FeS@NF nanosheet arrays for high-performance electrocatalytic oxygen evolution/urea oxidation, and overall water/urea splitting reactions

To develop non-noble electrocatalysts with high activity and stability for oxygen evolution reaction (OER)/urea oxidation reaction (UOR) is crucial to boost the efficiency of overall water/urea splitting reaction (OWS/OUS) for H-2 production. Herein, we synthesized novel CeO2/Co(OH)(2)/FeS nanosheet arrays on nickel foam (CeO2/Co (OH)(2)/FeS@NF) through a simple two-step hydrothermal and following solvothermal routine. In this special structure, the ultra-thin 2D nanosheet morphology can adequately offer large contact area and thus abundant of active sites, facilitating significantly the mass transfer. Furthermore, the incorporation of FeS into CeO2/Co(OH)(2) will not only modify the electron structure but also provide a number of phase interfaces, which can improve the inherent electron conductivity and promote the electron transport. More importantly, the rich oxygen vacancies (Ov) sites can vary the coordination of metal centers, modulating both the charge distribution and M-O bonding strength. As results, the CeO2/Co(OH)(2)/FeS@NF shows superior low overpotentials of 178 mV/1.30 V at 10 mA cm(- 2) to OER/UOR. The activity keeps its low value of 232 mV/1.375 V even when the current density was increased to as high as 300 mA cm- 2. More importantly, the electrode of CeO2/Co(OH)(2)/FeS@NF//CeO2/Co (OH)(2)/FeS@NF just requires a low cell voltage of 1.41 V to realize OUS at a current density of 10 mA cm(- 2). Specifically, we also realized solar-driven H2 production. Plenty of H2 bubbles were continuously generated with a high speed of 600 L h(- 1) m(-2) on the working electrode surface once the solar panel was placed under the natural sunlight.