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Engineering 3D dual-functional electrodes with non-noble metals toward efficient overall water electrolysis is significantly important but challenging for the renewable chemical fuels. Here, vanadium doped Ni 3 S 2 nanosheets array decorated on carbon fiber cloth (V-Ni 3 S 2 /CC) is successfully constructed as 3D dual-functional electrodes for efficient overall water splitting. The specific nanosheet array electrode provides structural benefits of high contact area, abundant accessible catalytic sites, shortened and accelerated charge transfer, and improved electrolyte penetration. Moreover, the vanadium dopants have a positive effect on the catalysis process, contributing to the improved intrinsic activity and accelerated catalysis reaction kinetics of Ni 3 S 2 catalyst. Reasonably, the developed V-Ni 3 S 2 /CC electrodes exhibit robust water splitting performances, with small overpotential of 180 mV for oxygen evolution reaction and 81 mV for hydrogen evolution reaction at 10 mA cm−2. In a V-Ni 3 S 2 /CC dual-electrodes constructed electrolyzer system, an ultralow cell potential of 1.49 V is achieved for a stable catalytic current of 10 mA cm−2, outperforming most of the reported non-noble metals based dual-functional electrocatalysts. Unlabelled Image • Vanadium doped Ni 3 S 2 nanosheet array for overall water splitting. • Nanosheet array supplies structure benefits for improved electrocatalysis. • V dopants improve both intrinsic activity and reaction kinetics. • Excellent HER, OER, and overall water splitting activities are achieved. [ABSTRACT FROM AUTHOR]

S-doped CoP nanoneedles assembled urchin-like structure on carbon cloth is prepared to demonstrate the boosting effects of nonmetal element doping and morphology controlling engineerings on OER performances for alkaline water splitting. [Display omitted] • S-doped CoP nanoneedles assembled urchin-like structure is grown on carbon cloth. • S doping brings more active sites and enhanced catalysis kinetics. • Nanoneedles assembled urchin-like structure benefit high surface area fast charge transfer. • Improved OER efficiency in alkaline media are obtained. The electrocatalysts with low-price and high-efficiency for oxygen evolution reaction (OER) are of significant importance for water splitting, which is believed as the promising technique for future sustainable energy system. Herein, sulfur is doped into carbon cloth supported CoP nanoneedles assembled urchin-like structure to acquire improved intrinsic catalysis efficiency, fast charge diffusion, and additional catalysis sites for enhanced OER performance. The specific urchin-like assembly structure is beneficial for highly exposed active sites and short charge transfer path for catalysis. Benefited from the advantages, the obtained sample exhibits advanced OER activity even better than RuO 2 in alkaline solution, achieving low overpotentials of 248 and 380 mV at current densities of 10 and 100 mA cm−2, respectively. This study may set a blueprint for exploring efficient transition metal pounds based catalyst for water splitting with nonmetal doping engineering. [ABSTRACT FROM AUTHOR]

• Core-shell catalyst of graphene layer coated MoNi 4 -NiMoO 4 is developed. • High intrinsic activity and large ECSA are achieved. • Graphene layer accelerates charge transfer and benefits for durability. • Low overpotentials of 55 and 206 mV at 10 mA cm−2 for HER and OER. • High bifunctionality of 1.44 V at 10 mA cm−2 for overall water splitting. Developing active and cheap bifunctional electrocatalysts is crucial and challenging for overall water splitting. This work reports a core-shell structured catalyst supported on nickel foam, which is composed of hybrid MoNi 4 alloy and NiMoO 4 encapsulated in graphene shell layer. The core catalyst of MoNi 4 -NiMoO 4 supplies robust intrinsic activity and high conductivity. The graphene shell accelerates the charge transfer and provides additional protection for core catalyst. Hence, the present G@MoNi 4 -NiMoO 4 /NF exhibits excellent catalytic properties for alkali water splitting, with low overpotentials of 55 mV and 206 mV at 10 mA cm−2 for HER and OER, respectively. The efficient activity for overall water splitting is further demonstrated by a low cell voltage of 1.44 V at 10 mA cm−2 in the bifunctional G@MoNi 4 -NiMoO 4 /NF electrodes assembled electrolyzer, showing great promise for practical application. [ABSTRACT FROM AUTHOR]