Boosting carbonate radicals production to enhance photocatalytic Degradation of micropollutants.

Reversing the detrimental effects of complex water matrices (e.g., HCO) on micropollutant degradation through modulation of the reaction pathway remains a major challenge. Herein, we proposed a novel and unique reduction pathway to generate •CO at high concentrations of bicarbonate for efficient and robust water purification. Mechanistic investigations demonstrated that photogenerated electrons (e) from graphitic carbon nitride with nitrogen vacancies (CN-V) promoted the in-situ activation of peroxymonocarbonate for •CO rapid generation from bicarbonate in the water matrix. Such a unique reduction pathway enhanced the production of highly reactive •CO, resulting in a significant 6.85-fold increase in the degradation of sulfamethoxazole compared with the absence of HCO. The theoretical calculations and controllable synthesis strategy validate the crucial role of in-situ capture and utilization of photogenerated e in •CO₃⁻ production, and modulate the level of nitrogen vacancies for optimal performance. The CN-V/HCO photocatalytic system exhibited satisfactory decontamination performance in inorganic anions, organic matter and even practical water matrices. Moreover, CN-V was immobilized in a continuous-flow photoreactor to constantly and efficiently remove pollutants, indicating the great potential for water purification. Overall, this work provides a novel insight into the mechanism of •CO production, and offers an effective technique for water purification.