The introduction of oxygen-defects has been a versatile strategy to enhance photocatalysis efficiency. In this work, a 2D/3D Bi/BiO 2-x /Bi 2 WO 6 heterojunction photocatalyst with rich oxygen-defective was in sequence prepared through a facile solvothermal method , which displays favorable photocatalytic activity towards organic contaminants under visible-NIR light irradiation . The enhancement in photocatalytic performance can be attributed to the synergistic effect between oxygen-vacancy-rich heterojunction and the localized surface plasmon resonance induced by metallic Bi. The functional group interaction, surface morphology , crystal structure, element composition , and tuned bandgap were investigated by FT-IR, SEM, Raman shift, ICP-MS, and XPS technique. The spectrum response performance of the photocatalyst was verified by UV–visible DRS analysis. Results of photodegradation experiments toward organic contaminants showed that the prepared photocatalyst can degrade 90% of phenol in 20 mins under visible-NIR light irradiation, both Z-scheme heterojunction and the introduction of Bi metal contribute to the enhancement in the photocatalytic activity. The results of the DFT calculation suggest that the valence band-edge hybridization within BiO 2-x and Bi 2 WO 6 can effectively enhance the photocatalytic performance by increasing the migration efficiencies of electron-hole pairs. Moreover, a possible mechanism was proposed on the results of EIS, ESR and GC–MS tests. This work offers a novel insight for synthesizing efficient visible-NIR light photocatalysis by activating the semiconductors with Bi metal.
Xiaoxue Yang,Xiaoqing Liu,Dan He,Yifu Hu,Xiaojing Wang
Tetracyclines (TCs) are one of the most common types of antibiotics. In this investigation, a 2D–2D BiO 2−x /Bi 2 WO 6 composite has been assembled via growing Bi 2 WO 6 in situ on the sheets of BiO 2−x by a simple hydrothermal process and has been applied to removal residual TCs in waterbody. The XRD , SEM, TEM , and XPS analyses reveal that BiO 2−x /Bi 2 WO 6 composite is a compact 2D–2D heterojunction and exhibit rich oxygen vacancy . Among the series of composites with the different ratios, 20BiO 2−x /Bi 2 WO 6 displays a more excellent visible-light photocatalytic performance with a 96.4% degradation rate of TC, compared to pure Bi 2 WO 6 (47.9%) and BiO 2−x (73.3%). The enhanced photodegraded mechanism is revealed in view of the XPS analysis, ESR spectra and density function theory (DFT) calculation. The excellent photocatalytic performance is attributed to the BiO 2−x /Bi 2 WO 6 heterojunction and the generation of more oxygen vacancies originated from the co-shared Bi species and redox couple Bi 5+ /Bi 3+ pairs in composite, which will increase the light trapping ability, accelerate the electron transfer , induce a strong redox, and lead to the excellent photo-degraded activity for aqueous TC. This research provides a new insight into the development of the novel bismuth base photocatalyst via growing in situ strategy in the application to photo-catalytically decompose aqueous antibiotic residues.
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