From structure to function: Mechanistic exploration of calcium and strontium in carbon-doped boron nitride for enhanced nitric oxide oxidation

Abstract

Heterogeneous photocatalysis rarely employs main group metals as active centers due to the lack of available d orbitals. In this study, alkaline earth metal centers were introduced into a carbon-doped boron nitride framework, leading to an optimization of their electronic structure and successful activation of catalytic activity. Interestingly, these metal centers were found to effectively utilize d orbitals or d/p hybrid orbitals to activate O2 and H2O, thereby generating a wealth of reactive oxygen species (ROS), which efficiently convert NO to NO3-. In addition, the optimized alkaline earth metal structural unit can not only strengthen carrier separation, but also improve the adsorption behavior of NO2 on the catalyst surface and promote its further conversion to NO3-. This research provides new insights into the design of highly active sites and the exploration of catalytic mechanisms for alkaline earth metals.