Construction of BiOI/UiO-66(Ce/Fe) S-scheme heterojunction for enhancing photocatalytic activity

With growing concerns about antibiotic contamination in water environments, developing efficient photocatalysts for tetracycline (TC) degradation has become imperative. In this study, a novel nanoflower-like BiOI/UiO-66(Ce/Fe) S-scheme heterojunction photocatalyst was developed for efficient TC degradation under visible light. Experimental evaluations revealed that the optimized 0.05-Bi/U(Ce/Fe) sample achieved 99.5 % TC degradation efficiency, maintaining 88.8 % of its initial activity after four consecutive cycles. The superior photocatalytic activity arises from three synergistic mechanisms: Fe 3+ doping modulates the band structure to broaden visible-light absorption, while the synergistic effect of Ce 4+ /Ce 3+ and Fe 3+ /Fe 2+ redox pairs optimizes charge transport. The internal electric field at the BiOI/UiO-66(Ce/Fe) heterojunction enhances charge separation while maximizing the redox capacity of the photocatalyst. Radical capture experiments and LC-MS analysis confirmed ·O 2 − and ·OH as the dominant reactive radicals, with proposed possible degradation pathways. Thus, a new synergistic strategy for designing efficient photocatalysts is proposed in this work.