Electrochemical water splitting is an effective way to produce green hydrogen, but the sluggish kinetics of the anodic oxygen evolution reaction （OER） limits its large-scale application. In this paper, ultrathin CoAl-LDH dodecagonal nanosheets were first prepared using the liquid reflux method. The large surface area of these nanosheets makes them a good catalyst support, and the large amount of unsaturated Co²⁺ on the surface can effectively coordinate other anions. Co-precipitation and ion exchange methods were then integrated to assemble a large number of ultra-small CoFe-PB nanoparticles on the surface of CoAl-LDH nanosheets, forming a CoAl-LDH/CoFe-PB heterostructure. Finally, the CoAlP/CoFeP_x@NC heterostructure was obtained through an in situ phosphating strategy. During the phosphating process, the CoFe-PB nanoparticles are transformed into nitrogen-doped carbon-wrapped CoFeP_x core-shell nanoparticles to provide sufficient active sites.
At the same time, CoFeP_x is firmly loaded onto the surface of CoAlP nanosheets that were converted from CoAl-LDH, forming a stable heterostructure. With the help of abundant components, unique porous structure, and stable lamellar structure, the CoAlP/CoFeP_x@NC heterostructure can obtain excellent electrocatalytic OER activity. In an alkaline electrolyte （1 mol·L^-1 KOH）, the overpotential of CoAlP/CoFeP_x@NC at a current density of 10 mA·cm^-2 is 334 mV （vs. RHE）. This study provides ideas for the design and preparation of low-cost, stable and efficient multi-metal phosphide-based heterostructure electrocatalysts.