Photocatalysis

About: Photocatalysis is a research topic. Over the lifetime, 67088 publications have been published within this topic receiving 2145233 citations. The topic is also known as: photocatalyst.

Facile Fabrication of Highly Efficient g-C3N4/Ag2O Heterostructured Photocatalysts with Enhanced Visible-Light Photocatalytic Activity

Abstract: Highly efficient visible-light-driven g-C3N4/Ag2O heterostructured photocatalysts were prepared by a simple liquid phase synthesis method at room temperature. The composition, structure, morphology, and optical absorption properties of the as-prepared g-C3N4/Ag2O composites were characterized by XRD, FTIR, XPS, TEM, and UV–vis DRS, respectively. We found interestingly that the photogenerated charge carriers separations of the as-prepared g-C3N4/Ag2O composites were closely related to the mass ratio of g-C3N4 and Ag2O. When the mass ratio of g-C3N4 and Ag2O reached 1:4, the as-prepared composite exhibited the highest photocatalytic activity, which was almost 11 and 1.2 times as high as that of individual g-C3N4 and Ag2O, respectively. The enhancement of photocatalytic activity could be attributed to the synergetic effects between g-C3N4 and Ag2O as well as the improved dispersibility and the decreased particle size of Ag2O. Moreover, the as-prepared composites showed excellent stability toward the photodeg...

Synthesis and structure of nanocrystalline TiO2 with lower band gap showing high photocatalytic activity.

Abstract: Nanocrystalline TiO2 was synthesized by the solution combustion method using titanyl nitrate and various fuels such as glycine, hexamethylenetetramine, and oxalyldihydrazide. These catalysts are active under visible light, have optical absorption wavelengths below 600 nm, and show superior photocatalytic activity for the degradation of methylene blue and phenol under UV and solar conditions compared to commercial TiO2, Degussa P-25. The higher photocatalytic activity is attributed to the structure of the catalyst. Various studies such as X-ray diffraction, Raman spectroscopy, Brunauer−Emmett−Teller surface area, thermogravimetric−differential thermal analysis, FT-IR spectroscopy, NMR, UV−vis spectroscopy, and surface acidity measurements were conducted. It was concluded that the primary factor for the enhanced activity of combustion-synthesized catalyst is a larger amount of surface hydroxyl groups and a lowered band gap. The lower band gap can be attributed to the carbon inclusion into the TiO2 giving Ti...

Enhanced Photocatalysis of Electrospun Ag−ZnO Heterostructured Nanofibers

Abstract: A unique dimer-type heterostructure of Ag−ZnO nanofibers with a diameter of 80−150 nm and coupled Ag nanoparticles in the size range from several to 15 nm have been fabricated by a facile electrospinning method. Rhodamine B (RhB) was employed as a representative dye pollutant to evaluate the ultraviolet (UV) photocatalytic activity of Ag−ZnO nanofibers. It was found that the heterojunction structure promoted the charge separation as well as the photon efficiency, allowing both the photogenerated electrons and holes to participate in the overall photocatalytic reaction. The optimal photocatalytic activity of Ag−ZnO nanofibers exceeded that of pure ZnO nanofibers by a factor of more than 25. A possible mechanism for the enhanced photocatalytic activity of ZnO by Ag was proposed.

Highly Selective Production of Hydrogen Peroxide on Graphitic Carbon Nitride (g-C3N4) Photocatalyst Activated by Visible Light

Abstract: Photocatalytic production of hydrogen peroxide (H2O2) on semiconductor catalysts with alcohol as a hydrogen source and molecular oxygen (O2) as an oxygen source is a potential method for safe H2O2 synthesis because the reaction can be carried out without the use of explosive H2/O2 mixed gases. Early reported photocatalytic systems, however, produce H2O2 with significantly low selectivity (∼1%). We found that visible light irradiation (λ > 420 nm) of graphitic carbon nitride (g-C3N4), a polymeric semiconductor, in an alcohol/water mixture with O2 efficiently produces H2O2 with very high selectivity (∼90%). Raman spectroscopy and electron spin resonance analysis revealed that the high H2O2 selectivity is due to the efficient formation of 1,4-endoperoxide species on the g-C3N4 surface. This suppresses one-electron reduction of O2 (superoxide radical formation), resulting in selective promotion of two-electron reduction of O2 (H2O2 formation).