Interface engineering of Fe-Co3N/CoP composite with N-doped C by using soybean: Fabrication of efficient electrocatalysts for oxygen evolution reaction

Soybean can serve as an efficient carbon and nitrogen source for in-situ fabrication of efficient composite electrocatalysts with conductive nitrogen-doped carbon (N-C) material. In this study, the iron-doped cobalt nitride/phosphide (Fe-Co₃N/CoP) nanosheet was composited with a conductive N-C material by using soybean as C and N source, as well as NH₃ as additional nitrogen source. During the nitridation process of Fe-Co₃N, N-C bond was formed as a newly generated Co(Fe)-N-C active sites. Therefore, it fabricates a good microscopic contact interface between the catalyst and carbon material for charge transfer. Besides, the introduction of Fe-CoP by partially phosphating Fe-Co₃N further improved the OER activity due to the high catalytic activity of Co sites with high valence state. As a result, the obtained electrocatalyst exhibited overpotentials as low as 285 and 390 mV for supporting 10 and 100 mA/cm⁻² current densities. This work indicates that the design of materials with good interfaces could be an effective approach for the preparation of electrocatalysts for water electrolysis.