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The development of transition metal electrocatalysts to replace precious metal electrocatalysts is essential for the development of sustainable water splitting technology for the mass production of clean hydrogen. FeCoNiS/NVG (N-doped vertically oriented graphene) is fabricated via single-step electrodeposition. Benefiting from the vertical structure of FeCoNiS/NVG and intrinsic catalytic activity of FeCoNiS, FeCoNiS/NVG displays excellent catalytic activities toward the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), with overpotentials of 126 and 347 mV at 10 mA cm-2, respectively. The overpotentials of FeCoNiS/NVG are similar to those of commercial Pt/C (100 mV) and IrO2 (329 mV). The Faraday efficiency of FeCoNiS/NVG for overall water splitting is about 95%. FeCoNiS/NVG also exhibits long-term stability for HER and OER. This work demonstrates the great potential of iron-group metal sulfides for overall water splitting. [ABSTRACT FROM AUTHOR]

FeCoxNiyB nanoparticles with tuned cationic ratio integrated on Vertically Aligned Boron-doped Graphene Array (FeCoxNiyB@B-VG) electrocatalysts towards water splitting are successfully prepared by electroless plating. For a specific composition, FeCo66.7Ni33.3B@B-VG electrocatalyst exhibits the highest electrocatalytic activity towards hydrogen evolution reaction, with low overpotentials of 125 and 157 mV at ?10 and small Tafel slopes of 52 and 47 mV dec-1 in 1.0 M KOH and 0.5 M H2SO4 solution, respectively. FeCo66.7Ni33.3B@B-VG electrocatalyst displays remarkable catalytic activity towards oxygen evolution reaction by showing low overpotentials of 200 and 569 mV at ?10 and small Tafel slopes of 34 and 225 mV dec-1 in 1.0 M KOH and 0.5 M H2SO4 solution, respectively. The result of stability test exhibits that FeCo66.7Ni33.3B@B-VG electrocatalyst has long-term stability for at least 10 h towards water splitting in a wide pH range. And the faraday efficiency of FeCo66.7Ni33.3B@B-VG towards water splitting is around 90%. This study helps to explore the effect of variable cationic ratio in the fabrication of non-noble electrocatalyst to achieve enhanced electrocatalytic activity for water splitting in a wide pH range. [ABSTRACT FROM AUTHOR]