Tuning the Oxidative Activity of Single Atom Catalysts by Carbon Doping in Hexagonal Boron Nitride Supports

Single-atom catalysts (SACs) have gained significant attention due to their exceptional metal atom utilization efficiency and high catalytic activity. Using DFT calculations, single-atom metals (M = Ag, Au) on defective and carbon-doped h-BN supports (M@BN and M@nC-BN) are systematically investigated to elucidate the effects of C-doping concentration and configuration on their structural stability, and to explore their potential application in O₂ activation. The results indicate the singlet O₂ adsorbed configuration is more effective in activating the O-O bond than the triplet one. Ag@4C-BN and Au@6C-BN exhibit good stability comparable to their undoped counterparts. Compared to M@BN, the M@nC-BN surfaces, particularly M@4C-BN, exhibit significantly enhanced adsorption of singlet O₂, accompanied by the most notable O-O bond elongation, indicating its superior capability for O₂ activation. DOS and frontier orbital analysis reveals that C-doping upshifts the HOMO energy level of M@4C-BN, endowing the catalyst with a stronger electron-donating ability to O₂ 2π* and leading to efficient activation. This study provides a theoretical basis for the rational design and optimization of BN-based single-atom catalysts.