Combining SnO_2-x and g-C₃N₄ nanosheets toward S-scheme heterojunction for high selectivity into green products of NO degradation reaction under visible light

NO_x emissions cause many negative impacts on the living environment. The photocatalysis of semiconductors is superior for nitric oxide (NO) degradation due to their low redox potential. In this report, we combine SnO_2-x/g-C₃N₄ heterojunction photocatalyst toward the high selectivity into green products under visible light illumination. Results show that SnO_2-x/g-C₃N₄ heterojunction degraded 40.8% of NO, which is 1.6 times higher than that of g-C₃N₄. In addition, the selectivity coefficient of SnO_2-x/g-C₃N₄ is higher 3 times than both pure SnO_2-x and g-C₃N₄. Furthermore, SnO_2-x/g-C₃N₄ expresses a superior stability for NO photocatalytic-degradation after five cycles. The scavenger trapping test results, and electron spin resonance (ESR) analysis also provide more understanding of the charge transfer mechanism of materials. SnO_2-x/g-C₃N₄ heterojunction shows a high removal efficiency of NO gas, making it an up-and-coming environmental treatment candidate.