Visible-light-driven peroxymonosulfate activation by porous sulfur-doped g-C₃N₄ for the removal of organic contaminant

As a potential nonmetal activator of peroxymonosulfate (PMS), g-C₃N₄ becomes a hot material owing to its superior chemical and physical properties. Nevertheless, pristine g-C₃N₄ is unsatisfactory for PMS activation because of its limited photo-generated charge separation and low specific surface area. Herein, a porous sulfur-doped g-C₃N₄ (S-doped g-C₃N₄) has been prepared through a one-step calcination route without a template. The in-situ doping of sulfur element and the formation of porous morphology have been confirmed via various characterization methods. The catalytic activity of porous S-doped g-C₃N₄ is approximately 6.2-fold higher than that of the pristine g-C₃N₄ on rhodamine B (RhB) decomposition in aid of the photo-assisted PMS activation. The superior catalytic activity and high stability of the porous S-doped g-C₃N₄ catalyst in a wide pH range are attributed to its higher specific surface area, enriched active sites, efficient photo-induced charge separation, and increased visible-light utilization. Meantime, a synergistic effect between the PMS activation process and the photocatalytic process is conducive to produce abundant radicals for the RhB degradation. This study offers new insight into further developing highly efficient nonmetal heterogeneous catalysts for wastewater treatment.