Degradation and detoxification of neonicotinoid insecticides by a porous oxygen vacancy-rich BiOCl self-recovery system: Active site transfer enhances oxygen vacancies stability

Abstract

The development of efficient photocatalytic methods for the degradation of neonicotinoid insecticide contamination and the reduction of its toxicity presents significant challenges. Although oxygen vacancies can enhance catalytic performance, they often destabilize the catalyst. In this study, we constructed a self-recovering porous BiOCl with oxygen vacancies (POv-BOCs), which forms an in-lattice electron donor-acceptor system under visible light. In this system, the donor lattice oxygen donates electrons to generate oxygen, while the acceptor lattice Bi accepts these electrons to produce metallic Bi⁰. The released oxygen is captured by Bi⁰, which replace the oxygen vacancies as active sites, thereby endowing POv-BOCs with enhanced stability. The electrophilic characteristics of POv-BOCs significantly improve the degradation performance of neonicotinoid insecticides, and the degradation rate exhibited a positive correlation with their electronic affinity value. Although some nitrated byproducts formed during the degradation process initially increased toxicity, the persistent action of POv-BOCs ultimately induced toxicity reduction. This work presents an effective approach to enhancing the stability and photocatalytic performance of oxygen vacancies, which are highly significant for developing of oxygen vacancy catalytic systems and the degradation of electron-deficient pollutants.