Coordination engineering of single-atom copper embedded graphene-like borocarbonitrides for hydrogen production

Abstract

For single-atom catalysts (SACs), there is growing recognition of the impact of coordination environment to catalytic performance, and most efforts have been focused on examining the relationship. However, there are few theoretical studies of how to achieve satisfactory coordination environment, that poses a challenge to the operability of coordination engineering. Here, the synthesis, structure, electronic property and hydrogen evolution of SA Cu embedded in graphene-like borocarbonitrides, Cu1/g-BC6N, are investigated using density functional theory. The one-step and two-step synthesis methods are developed. The preference of vacant sites for Cu atoms varies with the temperature T and nitrogen pressure p, that guides coordination engineering. Localization/delocalization of electronic states of vacant sites is used to identify the coordination environment of Cu, that constitute active centers. The Cu at the vacant N site is potentially a good catalyst and photocathode for hydrogen evolution reaction. The Tafel reaction and Cu dimerization barriers are computed to assess the stability and reusability. Our work not only presents a facile and universal strategy to regulate the coordination environment, but also provides an insight into the environment optimization of coordination engineering for enhancing hydrogen evolution activity of g-BCN-based SACs.