Search

A high-efficient, low-cost, and em-friendly catalyst is highly desired to activate peroxides for environmental remediation. Due to the potential synergistic effect between bimetallic oxides' two different metal cations, these oxides exhibit superior performance in the catalytic activation of peroxymonosulfate (PMS). In this work, novel Mn1.8Fe1,204 nanospheres were synthesized and used to activate PMS for the degradation of bisphenol A (BPA), a typical refractory pollutant. The catalytic performance of the Mn,1.8Fe1204 nanospheres was substantially greater than that of the Mn/Fe monometallic oxides and remained efficient in a wide pH range from 4 to 10. More importantly, a synergistic effect between solid-state Mn and Fe was identified in control experiments with Mn304 and Fe304. Mn was inferred to be the primary active site in the surface of the Mn,.3Fe1204 nanospheres, while Fe(III) was found to play a key role in the synergism with Mn by acting as the main adsorption site for the reaction substrates. Both sulfate and hydroxyl radicals were generated in the PMS activation process. The intermediates of BPA degradation were identified and the degradation pathways were proposed. This work is expected to help to elucidate the rational design and efficient synthesis of bimetallic materials for PMS activation. [ABSTRACT FROM AUTHOR]

Tungsten oxide (WO3) has unique physicochemical properties. Although various synthetic methods have been proposed to fabricate tungsten oxide with different morphologies, methods of tailoring the tungsten oxide nanostructure toward new morphologies are still needed. In this work, a self-assembled WO3·0.33H2O nanoflower is synthesized using a dissolution and regeneration method. In such a two-step synthetic process, temperature, solvent, and reaction times are found to be the main parameters affecting the morphology of WO3·0.33H2O. The synthesized WO3·0.33H2O nanoflower exhibits a localized surface plasmon resonance effect and a high photocatalytic activity, which can be explained by the doping of W5+ and its morphology. Furthermore, this WO3·0.33H2O nanoflower can also be used as a gas sensor and has good selectivity and linearity towards acetone vapor in the range of 50-500 ppm. [ABSTRACT FROM AUTHOR]

The use of bismuth oxyhalides as photocatalysts has received extensive interest because of their high photocatalytic activity and stability. However, available methods for the synthesis of bismuth oxyhalides with tailored morphologies, well-defined facets, and tunable band gaps are still lacking. In this work, two-dimensional BiOCl xBr1− x solid solution with exposed {001} facets and tunable band gaps were synthesized by using solvothermal methods. The BiOClxBr1−x solid solution nanoplates crystallized in a homogeneous crystal structure but possessed continuously tuned band gaps from 3.39 to 2.78 eV by decreasing the ratio of Cl/Br. Among the synthesized nanoplates, the BiOCl0.5Br0.5 sample exhibited the highest photocatalytic activity for degrading Rhodamine B (RhB), a typical organic pollutant, under visible light. The highest photoactivity of the BiOCl0.5Br0.5 sample was attributed to a synergetic effect of higher surface area, facets exposed, and optimized band structure. The results are of profound significance for the design of novel photocatalyst materials. [ABSTRACT FROM AUTHOR]

Ammonia (NH 3 ), is a precursor for the formation of atmospheric fine particulate matter (PM 2.5 ), and thus establishing efficient and cost-effective methods to detect ammonia emission is highly desired. Transition metal oxide semiconductors-based sensors for electrochemical gas sensing have been extensively explored. Among various types of semiconductors, tungsten oxide (WO 3 ) possesses an anisotropic layered crystalline structure and is recognized as a promising material for gas sensing. However, the performance of commercial WO 3 is unsatisfactory because of its high impedance and low charge transportation efficiency. Thus, the modification of commercial WO 3 is needed to make it an efficient ammonia sensor material. In this work, closely packed WO 3 microspheres with oxygen vacancies were synthesized successfully through a novel two-step hydrothermal route. Our WO 3 showed a good selectivity to ammonia sensing, and its response intensity was 2.6 times higher than that of commercial WO 3 because of its optimized conductivity. Moreover, the mechanism behind its robust ammonia sensing performance was elucidated. The effectiveness of the as-prepared WO 3 microspheres for ammonia sensing also suggests a new strategy for modifying transition metal oxide materials., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

A high-efficient, low-cost, and eco-friendly catalyst is highly desired to activate peroxides for environmental remediation. Due to the potential synergistic effect between bimetallic oxides' two different metal cations, these oxides exhibit superior performance in the catalytic activation of peroxymonosulfate (PMS). In this work, novel Mn 1.8 Fe 1.2 O 4 nanospheres were synthesized and used to activate PMS for the degradation of bisphenol A (BPA), a typical refractory pollutant. The catalytic performance of the Mn 1.8 Fe 1.2 O 4 nanospheres was substantially greater than that of the Mn/Fe monometallic oxides and remained efficient in a wide pH range from 4 to 10. More importantly, a synergistic effect between solid-state Mn and Fe was identified in control experiments with Mn 3 O 4 and Fe 3 O 4 . Mn was inferred to be the primary active site in the surface of the Mn 1.8 Fe 1.2 O 4 nanospheres, while Fe(III) was found to play a key role in the synergism with Mn by acting as the main adsorption site for the reaction substrates. Both sulfate and hydroxyl radicals were generated in the PMS activation process. The intermediates of BPA degradation were identified and the degradation pathways were proposed. This work is expected to help to elucidate the rational design and efficient synthesis of bimetallic materials for PMS activation.

A series of BiOBrxI(1-x) solid solutions were explored as novel visible light-sensitive photocatalysts. These BiOBrxI(1-x) solid-solution photocatalysts grew into two-dimensional nanoplates with exposed (001) facets and possessed continuously modulated band gaps from 2.87 to 1.89 eV by decreasing the Br/I ratio. The photocatalytic activities of these samples were measured, and the samples exhibited visible light-driven activities for the degradation of Rhodamine B (RhB). In particular, BiOBr0.8I0.2 exhibited the highest activity for the degradation of RhB. This result could be attributed to the balance between the effective light absorption and adequate redox potential. Additionally, investigations into the photocatalytic mechanism showed that the photodegradation of RhB over BiOBr0.8I0.2 solid-solution photocatalysts involved direct holes oxidation, in which the reaction that dominated during photocatalysis was determined by the potential of the valence band. Furthermore, a high stability in the photocatalytic activity of BiOBr0.8I0.2 was demonstrated by the cycling photocatalytic experiment and long-term irradiation, which might offer opportunities for its practical application as a catalyst.

The use of bismuth oxyhalides as photocatalysts has received extensive interest because of their high photocatalytic activity and stability. However, available methods for the synthesis of bismuth oxyhalides with tailored morphologies, well-defined facets, and tunable band gaps are still lacking. In this work, two-dimensional BiOClx Br1-x solid solution with exposed {001} facets and tunable band gaps were synthesized by using solvothermal methods. The BiOClx Br1-x solid solution nanoplates crystallized in a homogeneous crystal structure but possessed continuously tuned band gaps from 3.39 to 2.78 eV by decreasing the ratio of Cl/Br. Among the synthesized nanoplates, the BiOCl0.5 Br0.5 sample exhibited the highest photocatalytic activity for degrading Rhodamine B (RhB), a typical organic pollutant, under visible light. The highest photoactivity of the BiOCl0.5 Br0.5 sample was attributed to a synergetic effect of higher surface area, facets exposed, and optimized band structure. The results are of profound significance for the design of novel photocatalyst materials., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)