CuBi2O4/Bi2MoO6 heterojunction photocatalyst for degradation of tetracycline and rhodamine B: preparation, characterization, and mechanism study

The efficiency of photocatalysts has historically been constrained by the suboptimal utilization of solar energy and the swift recombination of photogenerated charge carriers. To address this challenge, in situ growth of Bi2MoO6 nanosheets on CuBi2O4 surfaces to create a heterostructure has shown promising results. Our research focused on evaluating the degradation efficiency of pollutants by varying the proportions of CuBi2O4 and Bi2MoO6. The experiments determined that the 0.2CuBi(2)O(4)/Bi2MoO6 mixture exhibited the highest degradation efficiency. During the degradation of tetracycline and rhodamine B, the 0.2CuBi(2)O(4)/Bi2MoO6 composites achieved more than 90% effectiveness, significantly surpassing the efficiency of standalone CuBi2O4 and Bi2MoO6. This enhanced performance is primarily attributed to the heterojunction composition, which improves the migration efficiency of photon-generated carriers. In the degradation process, the most active species was identified as O-<middle dot>(2)-, with h(+) playing a supporting role. The 0.2CuBi(2)O(4)/Bi2MoO6 composites also demonstrated effective degradation in mixed solutions of TC and RhB. The material maintained its excellent degradation capability even after five degradation cycles, indicating its high stability. To elucidate the underlying mechanism of the CuBi2O4/Bi2MoO6 pn heterojunction photocatalyst, we conducted a comprehensive analysis using an energy band structure, free radical trapping, and electron spin resonance experiments. In addition, the degradation pathways and intermediates of TC were studied by LC-MS.