Low-temperature in situ fabrication of porous S-doped g-C3N4 nanosheets using gaseous-bubble template for enhanced visible-light photocatalysis

Abstract Developing one-step modification strategy for highly efficient metal-free g-C3N4 photocatalyst has always been challenging and yet demanding. In this study, we have demonstrated an in-situ low-temperature production of porous S-doped g-C3N4 nanosheets, using ammonium chloride (NH4Cl) as a gaseous-bubble template (GBT) to boost the visible-light photocatalytic degradation of organic pollutant dyes. The photocatalytic activities of GBT-induced porous S-doped g-C3N4 nanosheets (so-called p–SCN–x, x = mass ratio of NH4Cl/thiourea) were examined towards the degradation of Rhodamine B (Rh.B) under visible light. Importantly, both surface area and photocatalytic activities of the p-SCN–xsample were optimized by adjusting the mass fraction of thiourea/NH4Cl. The optimized p–SCN–2 exhibited a maximum photocatalytic degradation of 97.50%, which is 7.75-fold higher than that of GBT-free analogue (so-called bulk SCN-0). Moreover, the p–SCN–2 was tested for colorless tetracycline hydrochloride as an emerging pollutant, demonstrating 87% degradation under visible light irradiation. The enhanced performance of p-SCN–2photocatalyst was mainly attributed to an improved surface area, boosted light-harvesting range, and efficient electron-hole separation, and facilitated transfer of charge carriers by dye-sensitization mechanism. Moreover, the scavengers quenching study proved that the superoxide anion (•O2−) radicals and holes (h+) were the leading active sorts. In situ fabrication of p-SCN–x nanosheets at low temperature provided an inexpensive and green synthetic route for highly active g-C3N4–based photocatalysts that can resolve environmental pollution and clean energy issues.