Phosphorous-doped 1T-MoS2 decorated nitrogen-doped g-C3N4 nanosheets for enhanced photocatalytic nitrogen fixation

Herein, we report that the phosphorous-doped 1 T-MoS2 as co-catalyst decorated nitrogen-doped g-C3N4 nanosheets (P-1 T-MoS2@N-g-C3N4) are prepared by the hydrothermal and annealing process. The obtained P-1 T-MoS2@N-g-C3N4 composite presents an enhanced photocatalytic N2 reduction rate of 689.76 μmol L-1 g-1h-1 in deionized water without sacrificial agent under simulated sunlight irradiation, which is higher than that of pure g-C3N4 (265.62 μmol L-1 g-1h-1), 1 T-MoS2@g-C3N4 (415.57 μmol L-1 g-1h-1), 1 T-MoS2@N doped g-C3N4 (469.84 μmol L-1 g-1h-1), and P doped 1 T-MoS2@g-C3N4 (531.24 μmol L-1 g-1h-1). In addition, compared with pure g-C3N4 NSs (2.64 mmol L-1 g-1h-1), 1 T-MoS2@g-C3N4 (4.98 mmol L-1 g-1h-1), 1 T-MoS2@N doped g-C3N4 (6.21 mmol L-1 g-1h-1), and P doped 1 T-MoS2@g-C3N4 (9.78 mmol L-1 g-1h-1), P-1 T-MoS2@N-g-C3N4 (11.12 mmol L-1 g-1h-1) composite also shows a significant improvement for photocatalytic N2 fixation efficiency in the sacrificial agent (methanol). The improved photocatalytic activity of P-1 T-MoS2@N-g-C3N4 composite is ascribed to the following advantages: 1) Compared to pure g-C3N4, P-1 T-MoS2@N-g-C3N4 composite shows higher light absorption capacity, which can improve the utilization rate of the catalyst to light; 2) The P doping intercalation strategy can promote the conversion of 1 T phase MoS2, which in turn in favor of photogenerated electron transfer and reduce the recombination rate of carriers; 3) A large number of active sites on the edge of 1 T-MoS2 and the existence of N doping in g-C3N4 contribute to photocatalytic N2 fixation.