Electrodeposition-Solvothermal Access to Ternary Mixed Metal Ni-Co-Fe Sulfides for Highly Efficient Electrocatalytic Water Oxidation in Alkaline Media
By Zhao, Xin; Shang, Xiao; Quan, Yun; Dong, Bin; Han, Guan-Qun; Li, Xiao; Liu, Yan-Ru; Chen, Qi; Chai, Yong-Ming; Liu, Chen-Guang
Published in Electrochimica Acta
2017
Abstract
Abstract Ternary mixed metal Ni-Co-Fe sulfides based on three dimensional (3D) nickel foam (NiCoFeS/NF) have been synthesized via facile electrodeposition-solvothermal process. Firstly, a uniform film of Co-Fe oxides has been electrodeposited on the surface of 3D skeleton of {NF} (CoFe/NF). Secondly, an ethanol solvothermal sulfurization has been adopted to convert CoFe/NF to ternary mixed metal sulfides (NiCoFeS/NF). {XRD} confirms that ternary NiCoFeS is composed of mixed phases including NiS, Ni3S2 and Co3S4 phases but no Fe sulfides phase, implying amorphous state of Fe sulfides. {SEM} images of ternary NiCoFeS films shows uniform film covering on the surface of NF, which is composed of many hill-shaped bulges structures. The {OER} measurements confirm the excellent performance of ternary NiCoFeS/NF in 1.0 M KOH, providing low overpotential of 40 and 160 mV to drive 10 and 100 mA cm?2 in 1.0 M KOH, respectively. A further enhancement of the stability of NiCoFeS/NF have been conducted via a secondary electrodeposition of Fe on NiCoFeS/NF to obtain NiCoFeS-Fe/NF, with slightly lower overpotential of 230 mV to drive 100 mA cm?2 than that (310 mV) of NiCoFeS/NF after stability test. The role of Fe on {OER} ability and stability of NiCoFeS/NF have been discussed.