Phosphorus and kalium co-doped g-C3N4 with multiple-locus synergies to degrade atrazine: Insights into the depth analysis of the generation and role of singlet oxygen

In this work, with the help of KH2PO4, a phosphorus and kalium co-doped g-C3N4 with cyano and nitrogen vacancies (PKCN) have been prepared via a simple thermal treatment. The prepared PKCN exhibited excellent singlet oxygen (1O2) generation ability for the highly efficient degradation of atrazine (ATZ), reaching 95% (pH=5) of decomposition efficiency within 60 min under visible light. Density functional theory (DFT) calculation results visualize the role of cyano groups, nitrogen vacancies, K atoms and P atoms, and the synergistic effect of the above four aspects contributed to the three pathways of hole oxidation, energy transfer and dismutation reaction for efficient 1O2 generation. Moreover, the T.E.S.T and soybean culture experiment demonstrated the toxicity of ATZ have been significantly reduced after the photocatalytic process. This work can give deep insights into the roles and synergy of each active unit for designing and synthesizing efficient g-C3N4.