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The development of hydrogen production by water splitting was greatly limited by the slow kinetics of the oxygen evolution reaction (OER). Here, we found that the performance and efficiency of the electrocatalyst for OER can be improved by designing the defect structure of the nanocatalyst and heteroatom doping. In this study, we have successfully prepared defect-rich metal Fe-doped CoP nanosheets (noted as Fe–CoP NSs) as an efficient electrocatalyst for OER through an etching-cooperative strategy. The doping rate of the Fe element is about 0.18%. Surprisingly, Fe–CoP NSs possess a smaller overpotential (312 mV) and Tafel slope (56.1 mV dec–1) than commercial RuO2 (344 mV and 62.4 mV dec–1) to drive the current density of 10 mA cm–2 in 1 M KOH. In addition, Fe–CoP NSs have great stability and robustness, which was demonstrated by 20 h of chronoamperometry test and 2000 cyclic voltammetry cycles. The reasons for the excellent catalytic performance and robustness of Fe–CoP NSs may be ascribed to the facts that defect-rich NSs can expose more active sites and the heteroatom doping adjusts the electronic structure of the catalyst, thereby promoting the OER performance.

Doping rare-earth metals or introducing carbon into transition metal phosphides (TMPs) can promote the property and stability of water electrolysis. An original composite nanostructure, cerium-doped and carbon-coated CoMoO4 (Ce-doped CoMoO4@C), was obtained by a simple hydrothermal and annealing process successively. Subsequently, chemical vapor deposition (CVD) was adopted to synthesize carbon-coated and cerium-doped CoMoP/MoP (Ce-doped CoMoP/MoP@C) with diammonium hydrogen phosphate as the phosphorus source. Ce-doped CoMoP/MoP@C displayed superb bifunctional HER and OER catalytic performance under alkaline conditions. The overpotential η10, Tafel slope, and double-layer capacitance (C dl) for the OER were 287.0 mV, 74.4 mV dec–1, and 10.44 mF cm–2, while for the HER, these values were 188.0 mV, 72.2 mV dec–1, and 33.00 mF cm–2, respectively. Meanwhile, only 1.59 V (@10 mA cm–2) was needed to drive the entire water splitting. In addition, there was no apparent attenuation after electrolytic catalysis for 12 h continuously. The superb performance and endurance gave credit to the cooperative effect between carbon materials and metal phosphides and the optimized electronic structure by the incorporation of the Ce element.

Owing to the ionic doping and the partial phosphating strategies, Fe0.25-CoP catalyst exhibited remarkable catalytic activity and durability for electrochemical water splitting.

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