Interfacial charge polarization in Co2P2O7@N, P co-doped carbon nanocages as Mott-Schottky electrocatalysts for accelerating oxygen evolution reaction

Developing heterogeneous non-noble metal electrocatalysts to modulate the valence-electron state near the Fermi level of metal centers is the pivotal for efficient oxygen evolution reaction (OER). Herein, we report a Mott-Schottky heterojunction electrocatalyst of the Co2P2O7@N, P co-doped carbon nanocages, in which the metallic N, P co-doping carbon layer as a co-catalyst can effectively modulate the overfilled Co center eg orbital occupation of the Co2P2O7 nanoparticles and stabilize the microstructure. The density functional theory (DFT) calculations also reveal the build-in electric field promoted local charge polarization in the heterojunction interface greatly boosts the targeted intermediate (OOH*) adsorption with a higher intrinsic activity. The as-obtained electrocatalysts manifest superior OER catalytic performance with an overpotential of only 310 mV at a current density of 50 mA cm-2 and negligible current loss for 100 h in 1.0 M KOH, much lower than the benchmark RuO2 (370 mV). This work demonstrates a heterointerface charge polarization concept to accelerate OER in efficient electrocatalysts for water splitting.