High density cobalt single atom catalysts for H2O2 electrosynthesis: A critical design of carbon nitride skeleton

Abstract

Direct hydrogen peroxide (H2O2) electrosynthesis via the two-electron oxygen reduction reaction (ORR) provides aburgeoning alternative to the industrial anthraquinone process.In this work, based on first-principles calculations and a targeted structural search, we predicted a new two-dimensional (2D) carbon nitride monolayer, PH-CN, accompanied by high mechanical stability and adequate intrinsic pyrrolic N-rich network, such remarkable merits ensure its greatpotential as substrates. Herein, we demonstrate how the coordination environment regulates the electronic structure of the Co central atom and thus steers the ORR selectivity and activity using a series of control samples based on the most prevalent CoN4 moiety. As expected, the acquired P-CoN4 and PH-CoN4 show excellent H2O2electrosynthesis performance with low thermodynamic overpotential of 0.02 and 0.07 V, as well as extremely high Co loadings of 26.28 and 27.42 wt%, respectively. This work sheds light on how the carbon nitride skeleton affects catalytic activities on Co-N-C catalysts.