Design and enhancement of photocatalytic activity of porphyrin functionalized UiO-66 and Keggin unit co-doped titanium dioxide heterojunction

Abstract

The UiO-66-FP/HPW/TiO2 heterojunction photocatalytic material is fabricated by one-pot solvothermal method. The crystal structure, elemental composition, morphology, and optical properties of as-prepared catalysts are well-characterized. Subsequently, the synthesized materials’ catalytic activity is evaluated by degrading rhodamine B (RhB) and ofloxacin (OFX) under visible-light illumination. It turns out that the 10 wt% UiO-66-FP/HPW/TiO2 sample possesses the best efficiency, with 98.6% RhB and 97.2% OFX removed under identical condition, which is 4.68 and 4.14 times than that of HPW/TiO2, respectively. The superior efficiency can be ascribed to the construction of UiO-66-FP/HPW/TiO2 heterostructure, better adsorption capacity of organic contaminants, enhanced visible light response, and lower recombination rate of e−-h+ pairs. The quenching effect of distinct scavengers indicates that •OH is an additional significant contributor to the ternary photodegradation system besides •O2– and hVB+ species. This constitutes another reason for the superior photocatalytic activity of UiO-66-FP/HPW/TiO2 relative to HPW/TiO2. The photo-degradation efficiency of 10 wt% UiO-66-FP/HPW/TiO2 composite is reduced by 4.68% after running five cycles. Overall, this work presents one type of efficient and reusable TiO2-based photocatalysts driven by visible light.