Heterostructured BiOCO/rGO/PDA photocatalysts with superior activity for organic pollutant degradation: Structural characterization, reaction mechanism and economic assessment.

Compared with conventional methods for organic pollutant degradation, photocatalysis is a promising treatment technology with broad application prospects. BiOCO is often used for organic pollutants degradation but greatly restricted by having drawbacks of large band gap and high electron-hole recombination rate. Herein, heterostructured BiOCO (BOC)/reduced graphene oxide (rGO)/polydopamine (PDA) (BGP) photocatalysts were first designed through a green chemical method. By incorporating rGO and PDA in BOC, the kinetic constant of BGP to catalytically degrade methyl orange (MO) was significantly increased; over fourfold elevated rather than that of BOC (k = 0.0019, k = 0.0089) due to the high electron transfer capability of rGO and superior adhesive force and semiconducting properties of PDA. DRS and photoelectrochemical results confirmed the improvement of the light absorption range and charge transfer capability because of the synergistic effect of rGO and PDA. Results of trapping experiment and ESR unraveled the catalytic mechanism that both holes (h) and superoxide radicals (•O) were the main oxidative species for MO degradation. Economic assessment results demonstrated that BiOCO/rGO/PDA heterojunctions have great potentials in the field of organic wastewater purification. This study developed a low-cost and highly efficient BGP material and provided a deep understanding of the structure-performance relationships of materials for organic pollutant degradation.