In Situ Growth Strategy Synthesis of Single-Atom Nickel/Sulfur Co-Doped G-C3n4 for Efficient Photocatalytic Tetracycline Degradation and Co2 Reduction

Herein, a single-atom nickel/sulfur co-doped g-C3N4 (Ni/S-CN-N) was prepared via thermal polymerization of urea/thiourea complexes of nickel followed by secondary calcining with NH4Cl. The photocatalytic performances were evaluated by tetracycline (TC) degradation and CO2 reduction. The X-ray absorption fine structure measurements and theory calculation indicated that single-atom Ni was anchored on CN by forming the Ni-O/N bonds, and acted as active center to accumulate electrons. The NH4Cl-assisted calcining could increase the specific surface area. The apparent rate constant for TC degradation over optimized Ni/S-CN-N was 0.031 min−1, 6.0 times higher than pristine CN. Moreover, the Ni/S-CN-N exhibited high CO2 reduction rate with H2O. The CO and CH4 yields were 58.6 and 18.9 μmol g−1, respectively within 5 h, higher than that of pristine CN (CO: 7.9 μmol g−1, CH4: 0). This work provides a facile in situ growth strategy to construct single-atom metal modified CN for photocatalytic applications