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For the inverse opal photocatalyst, hydraulic pressure and other problems caused by the ordered structure of the inverse opal photocatalyst make it difficult for the pollutants to enter the structure quickly and effectively, so the effective control of its structure has become an urgent problem to be solved. Here, multi-heterojunction inverse opal structure catalyst with multi-level branched pore structure is prepared by the sol-gel method. The special three-dimensional dendritic porous structure solves the problem that a pollutant solution is difficult to effectively enter a skeleton with the traditional ordered inverse opal photocatalyst. This structure can also lead to the nanocrystallization of TZS powders, thus promoting the formation of the intermediate product ZrTiO 4 and optimizing the heterogeneous interface in the TiO 2 –ZrO 2 heterojunction, thereby successfully constructing the multi-heterostructure and effectively improving the redox ability. Furthermore, by adjusting the loading amount of TZS, the matching of the heterojunction and the inverse opal structure can be effectively controlled, the matching of the photonic band gap and the forbidden bandwidth can be effectively adjusted, and the degradation efficiency is greatly improved. This study provides a new idea for effective collaboration between multi-heterogeneous interfaces and 3D branch fractal structures. [ABSTRACT FROM AUTHOR]

BiSiO is a metastable phase compound and one of the important Bi-based Aurivillius phase oxide semiconductors. Pure BiSiO powders were synthesized successfully by Pechini sol-gel method. The samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, thermal analyzer, FTIR spectrometer, Raman spectrometer, fluorescence spectrophotometer and UV/Vis/NIR spectrophotometer. The mechanism of the reaction process was studied. The structure, the optical and photocatalytic properties of pure samples were investigated. The results show that citric acid, polyethylene glycol, solvents and calcination temperature have important effects on the reaction, and pure BiSiO can be obtained at 650 °C for 1 h. The as-prepared BiSiO has a typical Aurivillius-like structure and its bang gap energy is 3.5 eV. The results of degradation of Rhodamine B reveal that pure BiSiO powders prepared by Pechini sol-gel method possess a synergistic effect of adsorption and photocatalysis, which indicates that the BiSiO powders can be used as an efficient material for wastewater treatment. [ABSTRACT FROM AUTHOR]

Using Bi(NO)·5HO and Si(OCH) as the starting materials, citric acid and polyethylene glycol (PEG)-6000 as the complexing agents, pure BiSiO powders with good photocatalytic activity were first prepared at low temperature via Pechini sol-gel method. The effect of calcination temperature on the preparation of pure phase as well as the photocatalytic properties was investigated. The thermal analysis and X-ray diffraction results showed that the crystallization temperature of BiSiO is about 400 °C and pure sample can be obtained at 550 °C. The infrared spectra indicated the pure BiSiO samples have an Aurivillius-like structure. Furthermore, the as-prepared BiSiO exhibited efficient photocatalytic activity in the decomposition of Rhodamine B due to a synergistic effect of adsorption and photocatalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • A ion exchange technology was used to construct double heterojunction catalysts containing solid solution. • The adsorption mechanism and catalytic performance of the catalysts are investigated. • The catalysts achieve rapid degradation of Rh B, MO and TCH under visible light condition. The search for a photocatalyst toward degradation of different organic dyes and antibiotic remains a challenging task due to the difficult of controllable micro-morphology and double heterojunction in the same photocatalytic system. Herein, a ion exchange technology was used to obtain double heterojunction Bi 12 SiO 20 /Bi 2 O 2 SiO 3 /BiOX (BOSX, X ∈ Cl, Br, I). Moreover, three series of two-dimensional materials Bi 12 SiO 20 /Bi 2 O 2 SiO 3 /BiOX m Y n (BSOXYK, X, Y ∈ Cl, Br, I, m + n = 1, K = m/n) containing solid solution were realized, which have excellent adsorption catalytic synergistic effect on rhodamine B, methyl orange and tetracycline hydrochloride. This synergistic effect of adsorption and catalysis is due to the change of material morphology, double heterojunction interaction and continuous band regulation. After regulation, this series of photocatalysts show good degradation effects on a variety of pollutants, namely, the degradation rate on 30 mg·L-1 Rh B, 50 mg·L-1 TCH and 10 mg·L-1 MO can up to 99 % (BSOCI4), 85% (BSOCI4) and 99% (BSOCI1) respectively, which makes this series of materials have a wide range of applications. Therefore, this work provides a new insight in exploring double heterojunction catalysts with solid solution to realize the degradation of different organic pollutions in the same system under visible light. [ABSTRACT FROM AUTHOR]

Synergy is essential to maximize the photocatalytic performance of the catalyst, which makes the preparation of photocatalytic materials with the synergistic effect of adsorption and catalysis become an attractive research direction. Therefore, we have prepared TiO 2 –ZrO 2 –SiO 2 nano-powders by simple Pechini sol-gel method, which can effectively improve the synergistic effect of adsorption and degradation of photocatalytic materials. The results demonstrate that TiO 2 –ZrO 2 –SiO 2 possesses excellent photocatalytic performance and adsorption ability. And it can be deduced that in the TiO 2 –ZrO 2 –SiO 2 system, SiO 2 is as for adsorbent, and TiO 2 and ZrO 2 act synergistically as a photocatalyst. The enhanced photocatalytic ability of TiO 2 –ZrO 2 –SiO 2 is attributed to the acceleration of mass transfer by adsorption process, narrowed bandgap (Eg = 2.9 eV) and effective charge separation rate resulting from the formation of Ti–O–Zr. This work also studied the synergy effect between adsorption and photocatalytic properties in TiO 2 –ZrO 2 –SiO 2 , and synergy factor β is used to evaluate the synergistic effect. Moreover β > 1 in first 30 min of visible light irradiation demonstrates that the remarkable synergistic effect exists in TiO 2 –ZrO 2 –SiO 2 compound system. • TiO 2 –ZrO 2 –SiO 2 photocatalyst with both adsorption and photocatalytic properties was successfully prepared. • β (synergy factor) which explains the adsorption-photocatalytic synergistic effect of TiO 2 –ZrO 2 –SiO 2 system is remarkable. • The adsorption-photocatalytic performance can be regenerated. [ABSTRACT FROM AUTHOR]

Ternary inverse opal TiO 2 -ZrTiO 4 -SiO 2 photonic crystal (IOPC-TZS) photocatalysts have been synthesized in-situ by a simple template method. The morphology and thickness of the inverse opal photocatalysts with photonic crystal structure were controlled and optimized in order to obtain the inverse opal structure while maintaining the crystalline phase. The photocatalytic performance among the IOPC-TZS photocatalysts of Rhodamine B removal is 27 times higher than P25, and the excellent catalytic stability is observed even after three testing cycles. Compared with previous TiO 2 -ZrTiO 4 -SiO 2 (TZS) powders, the OH radicals that appear in inverse opal photonic crystal structure play an important role in the RhB degradation due to the up-shifted band structure. The formation of the TiO 2 -ZrTiO 4 heterojunction, the slow-photon-effect and the existence of the oxygen vacancies caused by the high active surface among the IOPC structure, result in the synergistic effect of remarkably enhanced separation efficiency and improved redox capacity of the photo-induced charge carriers, which boost the photodegradation behavior to organic pollutants. Unlabelled Image • IOPC structure is controlled and optimized while maintaining the crystalline phase. • Photocatalytic performance among the IOPC-TZS is 27 times higher than P25. • OH radicals in IOPC structure play an important role compare to normal powders. • Synergistic effect of slow-photon-effect, heterojunction and oxygen vacancies [ABSTRACT FROM AUTHOR]