LaCoO3 acts as a high-efficiency co-catalyst for enhancing visible-light-driven tetracycline degradation of BiOI

Exploring noble-metal-free co-catalysts highly flexible for separating the photogenerated charge carriers is of prime importance for the visible-light-driven photocatalysis. Herein, three-dimensional flower-like BiOI microspheres were fabricated and applied to support noble-metal-free LaCoO₃ co-catalysts to construct a unique LaCoO₃/BiOI hybrid photocatalyst with a higher ability in charge separation. As expected, the optimum tetracycline degradation rate of LaCoO₃ (4.0 wt%)/BiOI was up to 0.0161 min⁻¹, which was nearly 3.4 fold larger than that of pure BiOI (0.0048 min⁻¹). The enhanced photocatalytic performance was mainly ascribed to the vital role of LaCoO₃ co-catalyst, which acted as an excellent electron collector for capturing the electrons generated by BiOI, effectively promoting the separation of photogenerated charge carriers and prolonging the lifetime of photo-induced electron-hole pairs at the same time. Furthermore, the active species trapping experiments revealed that the excellent photocatalytic activity was primarily driven by photogenerated holes and superoxide radicals. This work is expected to provide a new inspiration for rationally designing and fabricating noble-metal-free co-catalyst system with high efficiency applied in environment purification.     

分级微球BiOBr和BiOI的制备及光催化活性比较

以五水硝酸铋、溴化钠和碘化钾为原料,乙二醇为溶剂,采用一步溶剂热法制备了分级结构微球BiOBr和BiOI。比较了两种催化剂在可见光和模拟日光下对罗丹明B的降解效果。结果表明,在模拟日光和可见光下,BiOBr的催化活性要好于BiOI,同时对机理进行了深入探讨。     

Preparation and photocatalytic activity of BiOI/MnxZn1-xFe2O4 magnetic photocatalyst

BiOI/Mn_xZn_1-xFe₂O₄ magnetic photocatalysts were successfully prepared for the first time. With the degradation of simulated RhB wastewater as a pointer to the photocatalytic reaction and combined with Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible diffuse reflectance spectroscopy (UV–vis DRS), and vibrating sample magnetometer (VSM), the reasons influencing the photocatalytic performance of the magnetic photocatalysts were further explored. The excessive or insufficient Mn-Zn ferrite both leads to a relatively low photocatalytic activity. When the calcination temperature reaches to 200 and 400?°C, the photocatalytic activity is enhanced significantly, but the main active component in the photocatalysts has changed from BiOI to Bi₅O₇I at 400?°C. The nanocomposites prepared under alcohol water environment with hollow microspheres morphology possess a highly photocatalytic efficiency, and the RhB degradation rate within 4?h in the ethanol water environment is significantly higher than that in pure water (98% vs. 59%).     

3D cross-linked BiOI decorated ZnO/CdS nanorod arrays: A cost-effective hydrogen evolution photoanode with high photoelectrocatalytic activity

ZnO/CdS photoanode with an excellent photoelectrochemical (PEC) performance for water splitting to produce hydrogen, but its practical application is seriously hindered owing to the photocorrosion induced by photoholes on the surface of CdS. Herein, a 3D cross-linked heterostructure ZnO/CdS/BiOI nanorod arrays (NRAs) has been prepared by a simple solvothermal strategy. Under visible light illumination (λ > 420 nm), the ZnO/CdS/BiOI NRAs photoanode shows an excellent PEC activity and generates a photocurrent density of 9.12 mA cm⁻² at 1.1 V vs. RHE, which is 1.8 times higher than that of the ZnO/CdS NRAs photoanode in the alkaline electrolyte. Furthermore, the photoanode achieves a high photo conversion efficiency of 3.49% and a long-time stability over 6000 s. It is proposed that the BiOI nanosheets not only serve as protecting layer to restrain the photocorrosion of CdS, but also facilitate the charge separation in CdS by the virtue of the p-n junction formed between CdS and BiOI.     

碘氧铋光催化材料研究进展

近年来,针对碘氧化铋(BiOI)光催化材料改性的方法已经较为成熟,光催化能力得到了广泛的提升,但是BiOI光催化材料多为微纳米颗粒,回收和循环利用较困难,很容易引发二次污染。本文综述了对BiOI的改性方法以及在改性的同时提高循环利用性研究的现状,以便于后期方便工业化,并能有效地降低有机物光催化处理成本。     

BiOI/g-C3N4光催化降解甲基橙研究

以三聚氰胺为前驱物采用热聚合法制备了石墨相氮化碳（g-C₃N₄）,并在其表面原位合成了碘氧化铋（BiOI）,构筑了石墨相氮化碳-碘氧化铋复合材料。采用X射线衍射仪（XRD）、傅里叶变换红外光谱仪（FT-IR）、紫外可见漫反射仪（UV-Vis-DRS）等对催化剂进行了表征。结果表明,当BiOI与g-C₃N₄物质的量比为0.5时,BiOI/g-C₃N₄催化剂具有高分散的BiOI颗粒及适中的禁带宽度,吸附和降解甲基橙性能最佳。回流温度为120 ℃时制备的BiOI/g-C₃N₄催化剂具有适中的粒径、比表面积和表面羟基浓度,吸附和降解甲基橙性能最佳,且该催化剂具有良好的重复使用性能。     

TiO2/BiOI/CQDs: Enhanced photocatalytic properties under visible-light irradiation

In this study, TiO₂/CQDs(TC), TiO₂/BiOI(TB), TiO₂/BiOI/CQDs(TBC) were prepared via a step-by-step method. Photocatalytic properties of the samples were carried out under visible-light irradiation using methyl orange (MO) as the target molecular. Among the samples, TBC showed the best photocatalytic performance, and the photocatalytic efficiency of TBC was more than 2 times higher than that of TiO₂, TC and TB samples, respectively. The reasons for the improved photocatalytic performance were discussed in this paper.     

Fabrication of metal-doped BiOI/MOF composite photocatalysts with enhanced photocatalytic performance

An octahedron-like metal-organic framework (MOF) was successfully synthesized by the ultrasound irradiation synthesis method. Meanwhile, a novel visible-light-driven Cu-doped BiOI/MOF composite photocatalyst was also synthesized by the microwave irradiation. MOFs, a new class of porous crystalline materials, have attracted tremendous attention considering their broad applications because MOF possesses the repeated crystalline structures and thereby improving the harvest of solar energy and transportation of charge carriers. In this article, the result has revealed that the appropriate modification of BIOI by incorporating MOF and copper could reach the maximum hydrogen yield under visible light irradiation. The hydrogen evolution for 10% v/v lactic acid and 0.30 g L^?1 of 3In/BiOI/4MOF composite photocatalyst had the maximum of 269.1 μmol h^?1 g^?1 for 6 h. However, as the overall time in a course of irradiation is prolongated until 48 h, 3Cu/BiOI/4MOF has the higher hydrogen evolution efficiency (7685.2 μmol) than that of 3In/BiOI/4MOF. Therefore, this study has substantially demonstrated to enhance the photocatalytic efficiency of BiOI photocatalyst using MOF and copper modified BiOI.