Constructing P–O bridge at heterogeneous interface to enhance built-in electric field to facilitate the surface reconstruction of carbon coated OER catalyst

Abstract

Constructing heterostructures and facilitating surface reconstruction are effective ways to obtain excellent catalysts for the oxygen evolution reaction (OER). Surface reconstruction is a dynamic process that is affected by the built-in electric field of the heterostructure. In this study, P/N co-doped carbon-coated Ni-Co/Ni-CoO heterostructure was prepared by in situ acid etching, aniline polymerization, and pyrolysis. This method can form a tightly connected heterogeneous interface. It was found that introducing P–O bonds in the carbon shell can increase its work function, thereby enhancing the built-in electric field between the carbon shell and the core catalyst. Detailed characterizations confirm that the P–O bridge at the heterogeneous interface can provide an electron flow highway from the core to the shell. The generated carbon defects generated by P leaching during surface reconstruction also have strong electron-absorbing capacity. These effects promote the conversion of Co²⁺ to Co³⁺, thereby providing more highly active sites. The resulting catalyst shows significantly enhanced activity and stability. This study demonstrates the promoting effect of the built-in electric field on the surface reconstruction of the catalyst and emphasizes the importance of the construction of tightly connected heterogeneous interface, which is instructive for the design of excellent OER catalysts.