Search

A highly efficient MgBi2O6 (MBO)/TiO2 heterostructured photocatalyst for the evolution of H2 was successfully prepared using a one-step hydrothermal method. The phase structure, microstructure and optical properties of the MBO/TiO2 composites were investigated by various experimental techniques. A series of H2 production experiments were performed under visible light. The measured results indicated that the nanostructured MBO/TiO2 composite, with a stoichiometric molar ratio of MBO:TiO2 = 0.2%, displayed the best H2 production rate of 3413 μmol h−1 g−1. The excellent photocatalytic performance of the obtained composite material was due to the heterojunction formed between MBO and TiO2, which reduced the charge transfer resistance and accelerated the separation efficiency of the photogenerated electron–hole pairs. The reaction mechanism was also discussed in detail. [ABSTRACT FROM AUTHOR]

AgBr/MgBi 2 O 6 heterostructured photocatalysts were synthesized by the deposition-precipitation method. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), and UV–Visible diffuse reflectance spectroscopy (UV–Vis DRS) were employed to examine the phase structure, morphology and optical properties of the as-prepared samples. The photocatalytic activity was investigated by decomposing methylene blue (MB) solution under visible light irradiation (λ > 420 nm). AgBr/MgBi 2 O 6 composites exhibited significantly enhanced visible-light-driven photocatalytic properties in comparison with pure MgBi 2 O 6 and AgBr. When the molar ratio of AgBr to MgBi 2 O 6 was 3:1, the composite catalyst showed the optimal photocatalytic activity and excellent stability. The enhanced photocatalytic activity of AgBr/MgBi 2 O 6 composites was attributed to the formation of p-n heterojunction between AgBr and MgBi 2 O 6 , thereby resulting in the effective separation and transfer of photogenerated electrons-hole pairs. [ABSTRACT FROM AUTHOR]

The pyrochlore-type (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 (SBO) containing Bi3+ and Bi5+ mixed valent states was first investigated as a photocatalyst in our very recent work. To further improve the photocatalytic performance, SBO/TiO 2 heterostructured composites were successfully fabricated using a single-step hydrothermal method. The photocatalytic activity of as-prepared samples was evaluated by the degradation of methylene blue under visible light irradiation and photocatalytic hydrogen generation using water. SBO/TiO 2 composites exhibited remarkably enhanced photocatalytic activity and high stability. The enhancement of photocatalytic performance is attributed to the increase of light absorption and the separation of photogenerated carriers on the interface of SBO/TiO 2 heterostructured composites. • (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 /TiO 2 composites exhibit excellent photocatalytic activity and high stability in photocatalytic removal of MB and hydrogen evolution. • The mechanism of MB photodegradation and photocatalytic generating hydrogen under visible light on (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 /TiO 2 were explored. • The formation of heterojunction should be directly responsible for the enhancement in photocatalytic efficiency of composites. Accelerating the separation efficiency of photoexcited electron-hole pairs with the help of binary heterojunction structure is considered to be a promising approach for significantly enhancing the photocatalytic hydrogen production performance of TiO 2. Providing more (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 (SBO) catalysts to function as active sites of TiO 2 , together with the ability to construct heterojunction structures, is highly desirable for photocatalytic hydrogen evolution and pollutant photodegradation. To achieve this goal, in this work, (Sr 0.6 Bi 0.305) 2 Bi 2 O 7 /P25 (SBO/P25) binary heterojunction catalyst is formed in situ on the TiO 2 surface by a simple one-step hydrothermal method. To evaluate the feasibility of SBO/P25 as a very efficient photocatalyst for degradation of MB and photocatalytic hydrogen evolution, a series of photocatalytic experimental studies were carried out. The experimental result indicated that the existence of heterojunction structure in the SBO/P25 nanocomposites improves the photocatalytic activity of P25. The photocatalytic performance of H 2 evolution from water splitting and MB degradation for an optimal SBO/P25 photocatalyst reached 3.18 mmol g–1 h−1 and 3.42 × 10−2 min−1, respectively, which were 7.40 and 5.26 times higher than those of pure P25, respectively. The significantly improved catalytic capability on SBO/P25 is mainly ascribed to the enhanced visible light absorption and charge transfer in comparison with P25. In addition, SBO/P25 composites have excellent stability and recyclability, showing great potential for application in wastewater treatment and photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

The pyrochlore-type (Sr0.6Bi0.305)2Bi2O7 (SBO), containing Bi3+ and Bi5+ mixed valent states, was recently found to be used as a new visible light responsive photocatalyst. Novel SBO/SnO2 heterostructured composites were synthesized through a facile one-step hydrothermal method. The phase structure, morphology, chemical composition, and optical properties of the obtained samples were characterized by XRD, SEM, TEM, XPS, and UV-vis DRS. Compared to pure SBO and SnO2, the synthesized SBO/SnO2 composites exhibited significantly enhanced photocatalytic efficiency. The results indicated that the photoinduced holes and superoxide radicals play a dominant role and are the main reactive species during the degradation of Methylene Blue (MB) solution under visible light irradiation. Heterojunctions, formed in samples, directly contribute to the improvement of photocatalytic efficiency of SBO/SnO2 composites, since it not only broadens the light response range, but also accelerates the separation of photogenerated carriers. [ABSTRACT FROM AUTHOR]

The pyrochlore-type (Sr0.6Bi0.305)2Bi2O7 (SBO) containing Bi3+ and Bi5+ mixed valent states was first investigated as a photocatalyst in our very recent work. To further improve the photocatalytic performance, AgBr/SBO heterostructured composites were synthesized by using a deposition-precipitation method. The characterization of phase structure, morphology, microstructure, elemental composition, and optical properties of the obtained products were performed using X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM)TEM, X-ray photoelectron spectroscopy (XPS), UV-visible diffuse reflectance spectroscopy (UV-vis DRS). The photocatalytic activity of samples was evaluated by degrading methylene blue under visible light illumination. AgBr/SBO composites possess high stability and significantly enhanced photocatalytic performance. The improvement of photocatalytic activity is due to the enhanced light absorption and the separation of photoinduced electrons and holes on the interface of AgBr/SBO heterostructured composites. [ABSTRACT FROM AUTHOR]