Enhancing oxygen evolution reaction of CoP nanosheets via interfacial engineering with CoFe-LDH nanosheets

Recently, transition-metal phosphides have emerged as favorable electrocatalysts for facilitating oxygen evolution reactions (OERs). This study successfully synthesized a heterostructure comprising interconnected ultrathin nanosheet arrays of Co_xP grown on nickel foam (NF) through electrodeposition and phosphorization processes. Subsequently, a layer of CoFe layered double hydroxides (LDH) was electrodeposited onto the Co_xP/NF substrate, resulting in the formation of the heterostructure Co_xP@CoFe-LDH. The OER efficiency of the Co_xP nanosheets exhibited substantial improvement because of the more accessible active sites and faster electron transfer capability of the heterostructure system. This improvement can be attributed to the higher surface area and well-established interfacial coupling between the ultrathin nanosheets of Co_xP and CoFe-LDH. Consequently, the Co_xP6@CoFe2/NF anode displays remarkable performance in enabling OERs, requiring merely a minimal overpotential of 230 mV at a current density of 10 mA·cm⁻² in 1 M KOH. This result signifies a substantial improvement when compared to the performance of the bare Co_xP and CoFe-LDH samples. Moreover, the heterostructure system enhanced the structural durability during the OERs, leading to remarkable stability over a continuous operation period of 50 h.