Yiqiu Liu,Yi Zhou,Qijun Tang,Qian Li,Si Chen,Zhuxing Sun,Haiqiang Wang
To explore an efficient photocatalyst for NO pollution, a direct Z-scheme photocatalytic system is successfully fabricated by coupling Bi2WO6 with NH2-UiO-66 via a simple hydrothermal synthesis technique. The Z-scheme system promotes the NO photocatalytic oxidation activity with an optimum NO removal rate of 79%, which is 2.7 and 1.2 times that obtained by using only pristine Bi2WO6 and NH2-UiO-66, respectively. Simultaneously, superior selectivity for converting NO to NO3−/NO2− is observed. The enhanced photocatalytic performance of the Bi2WO6/NH2-UiO-66 hybrids is attributed to the following two aspects: (i) large specific area of NH2-UiO-66, which exposes more active sites and is beneficial to the adsorption and activation of NO; (ii) outstanding Z-scheme structure constructed between BiWO6 and NH2-UiO-66, which can improve the efficiency of the separation of electron–hole pairs and preserves the strong oxidation ability of hybrids. ESR analysis shows that ·O2− and ·OH contribute to NO removal. A possible photocatalytic mechanism of NO oxidation on the direct Z-scheme photocatalyst (BWO/2NU) under visible light irradiation is proposed. This work displays the BWO/2NU hybrid's potential for treating low-concentration air pollutants, and the proposed Z-scheme photocatalyst design and promotion mechanism may inspire more rational synthesis of highly efficient photocatalysts for NO removal.
Mingming Dong,Zewen Huang,Shuyong Yang,Peng Zhou,Shenghui Tu
The growing prevalence of antibiotic residues in aquatic environments, particularly recalcitrant antibiotics like tetracycline (TC), poses significant ecological risks. In this study, a novel Bi 2 WO 6 /Mo-doped BiVO 4 /NH 2 -UiO-66 (BBU) ternary heterojunction photocatalyst was successfully synthesized via a solvothermal method to enhance visible-light-driven TC degradation through component synergy. Systematic characterization revealed that Mo doping induced lattice distortion in BiVO 4 , while the incorporation of NH 2 -UiO-66 drastically increased the specific surface area from 23.647 to 398.804 m 2 ·g −1 , providing abundant active sites. Photoluminescence (PL) and Electrochemical Impedance Spectroscopy (EIS) analyses demonstrated that the optimized BBU-3 sample exhibited the lowest charge carrier recombination rate. Under visible light irradiation for 80 min, BBU-3 achieved 95.2% degradation of TC, with reaction kinetics 8.61, 15.76, and 5.01 times higher than those of pristine Bi 2 WO 6 , BiVO 4 , and binary heterojunctions, respectively. Degradation-trapping experiments and electron paramagnetic resonance (EPR) measurements indicate that h + , 1 O 2 and ·O 2 - are the primary reactive species, suggesting that this system is a synergistic radical-non-radical degradation system. Additionally, possible degradation pathways and intermediate toxicity were evaluated. This work offers a promising strategy for designing efficient bismuth-based MOF heterojunctions for antibiotic remediation in water.
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