Defect-Rich Fe-Doped CoP Nanosheets as Efficient Oxygen Evolution Electrocatalysts

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.