Enhancing photocatalysis for organic pollutant degradation: A study on core-shell S-scheme C/Cu PDA/BiOBr heterojunctions nanoreactors

Abstract

The formation of black nanoclusters by chelation between metal ions and dopamine is expected to be used for efficient utilization and conversion of solar energy. As a semiconductor material, BiOBr is widely used in the degradation of organic pollutants. However, its photocatalytic efficiency is limited by the wide band gap and the rapid recombination of photogenerated carriers. The construction of heterojunctions is considered to be an effective way to improve the photogenerated charge separation of BiOBr. However, the slow electron transfer is mostly due to poor interface contact and non-directional electron transfer inside the heterojunction. In this study, an S-scheme C/Cu PDA/BiOBr heterojunction photocatalyst was designed and constructed. It was used for the rapid photoreduction degradation of organic dye Congo red by in-situ chemical growth combined with freeze-drying two-step process. The optimal removal efficiency of Congo red by C/Cu PDA/BiOBr heterojunction can reach 100 %. The enhanced photocatalytic performance can be attributed to the following key factors: 1)The introduction of C/Cu PDA improves the conductivity of the material and the ability to respond to visible light, and increases the light absorption range. 2)High-quality heterogeneous interface reduces the rapid recombination of carriers. 3)The S-scheme heterojunction improves the spatial separation ability of photogenerated charges and retains the conduction band and valence band with strong redox properties. This study innovatively provides in-depth insights into the photoreduction of CR and demonstrates an environmentally friendly pollutant degradation method.