Bi atom sharing Co-Bi2O2CO3/BiOI S-scheme induced singlet oxygen-dominated photocatalytic oxidation system

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Endocrine disrupting chemicals (EDCs) interfere with the normal secretion, transport and metabolism of human hormones, thus affecting neurological, reproductive and immune functions. Photocatalysis is regarded as a facile organic degradation technique. The construction of heterojunctions can modulate the reactive oxygen species and enhance the photocatalytic performance of semiconductors. However, poor contact interfaces still severely limit carrier separation and transfer. Herein we have doped Co to modulate the band structure of Bi2O2CO3 while facilitating the in situ growth of BiOI on its surface via shared Bi atoms. This approach led to the development of a 2D/2D Co-Bi2O2CO3/BiOI (Co-BOC/BiOI) S-scheme heterojunction characterized by atomically close contact interfaces. Furthermore, the photo-electrochemical characterization results indicate that the light adsorption capacity, carrier separation and transport efficiency of the optimized Co-BOC/BiOI-3 are greatly improved. This system demonstrates almost 100% removal rate for three typical EDCs within 60 min. The degradation kinetic constants show an improvement by an order of magnitude compared to single BiOI and Bi2O2CO3. More importantly, O2•﹣, which is produced from O2 reduction on high negative conduction band, can be subsequently oxidized into 1O2 by photogenerated hole. Electron paramagnetic resonance and quenching experiments indicate that the organics degradation process is dominated by 1O2. This work offers new insights into the construction of high-quality S-scheme heterojunction interfaces for modulation of reactive oxygen species.