Understanding of the Dual Roles of Phosphorus in Atomically Distributed Fe/Co-N 4 P 2 over Carbon Nitride for Photocatalytic Debromination from Tetrabromobisphenol A.

Atomically dispersed Fe and Co on carbon nitride under an external phosphine (PH 3 ) atmosphere (P-Fe 1 Co 1 /CN) are prepared. Combined with the results of calculations and experiments, the formed P-induced bimetallic single atoms of Fe/Co-N 4 P 2 can provide more reactive sites to enhance optical performance. Meanwhile, the introduced P can coordinate with Fe and Co and change the sole nitrogen coordination environment via the bridging effect. Herein, on the one hand, the structure of Fe-P-Co enhances interactions of single atoms in heterogeneous metals, and, on the other hand, the formed Fe/Co-N 4 P 2 effectively changes the electron configuration in coordination centers. All of the abovementioned findings can enhance the photocatalytic performance of P-Fe 1 Co 1 /CN, achieving 96% removal and 51% debromination rates from tetrabromobisphenol A under visible light irradiation. The two efficiencies can be further improved under UV-vis light irradiation. The findings of this work reveal the dual roles of P in bimetallic single-atom catalysts, provide a facile method to synthesize P-assisted bimetal single-atom photocatalysts, and highlight the great potential of carbon nitride-based single atoms as photocatalysts.