Copper single atoms incorporated in crystalline carbon nitride for efficient photocatalytic activation of peroxymonosulfate toward bisphenol A removal with visible light

The activation of peroxymonosulfate (PMS) over carbon nitride-based photocatalysts towards refractory organic removal has received growing attention in wastewater treatment. In this study, we successfully synthesized copper single atoms incorporated into crystalline carbon nitride (Cu-CCN) and applied it to activate PMS towards bisphenol A (BPA) removal. The characterization and theoretical calculation results indicated that Cu-CCN had good crystallinity, outstanding charge separation and transfer ability, and numerous PMS adsorption and activation sites provided by Cu single atoms. Consequently, Cu-CCN demonstrated an enhanced ability to activate PMS for BPA degradation. The activity performance of Cu-CCN was affected by the experimental conditions at different levels, and the catalyst had good stability in structure and activity during cyclic runs. A plausible reaction mechanism was also proposed according to free radical trapping and quenching experiments. This oxidation process can efficiently degrade organic pollutants as well as reduce the toxicity. The findings of this work elucidated an efficient photocatalyst for activating PMS towards organic removal and might guide the design of other metal single-atom modified photocatalysts.