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.

Influence of chemical structure of dyes, of pH and of inorganic salts on their photocatalytic degradation by TiO2 comparison of the efficiency of powder and supported TiO2

Abstract: Anionic (Alizarin S (AS), azo-Methyl Red (MR), Congo Red (CR), Orange G (OG)) and cationic (Methylene Blue (MB)) dyes were degraded, either individually or in mixtures, by using UV-irradiated TiO 2 in suspension or supported on glass and on paper. The influence of the chemical structure of different dyes as well as that of pH and of the presence of inorganic salts on the photocatalytic properties of TiO 2 has been discussed. The role of adsorption is suggested, indicating that the reaction occurs at the TiO 2 surface and not in the solution. S and N hetero-atoms are respectively mineralized into SO 4 2− , NO 3 − and NH 4 + , except azo-groups which mainly formed N 2 which represents an ideal case for a decontamination reaction. The fate of nitrogen strongly depends on its initial oxidation degree. High photocatalytic activities have been found for TiO 2 coated on glass by the sol–gel method. Its efficiency was intermediate between those of PC-500 and P-25 powders. The efficiency of PC-500 TiO 2 sample, fixed on paper by using a binder, is slightly less important than that of the powder. The presence of a silica-binder with an acidic pzc is suggested to be at the origin of the decrease in efficiency.

Enhanced photocatalytic activity and stability of Z-scheme Ag2CrO4-GO composite photocatalysts for organic pollutant degradation

Abstract: Silver chromate-graphene oxide (Ag2CrO4-GO) composites are prepared by a facile precipitation method. The resulting Ag2CrO4-GO composites exhibit excellent photocatalytic activity and stability towards the degradation of the dyes and phenol in aqueous solution under visible-light irradiation. The optimal composite with 1.0 wt% GO content shows the highest photocatalytic activity for methylene blue (MB) degradation, which is 3.5 times that of pure Ag2CrO4 particles. The enhanced photocatalytic activity is mainly attributed to the formation of Ag2CrO4-GO Z-scheme heterojunction that can not only facilitate the separation and transfer of the photogenerated charge carriers, but also preserve a strong oxidation and reduction ability. The high photocatalytic stability is due to the successful inhibition of the photocorrosion of Ag2CrO4 by transferring the photogenerated electrons of Ag2CrO4 to GO. The present work provides a new understanding into design and fabrication of the GO/silver compound composite photocatalysts.

Boosting Photocatalytic Hydrogen Production of a Metal-Organic Framework Decorated with Platinum Nanoparticles: The Platinum Location Matters.

Abstract: Improving the efficiency of electron–hole separation and charge-carrier utilization plays a central role in photocatalysis. Herein, Pt nanoparticles of ca. 3 nm are incorporated inside or supported on a representative metal–organic framework (MOF), UiO-66-NH2, denoted as Pt@UiO-66-NH2 and Pt/UiO-66-NH2, respectively, for photocatalytic hydrogen production via water splitting. Compared with the pristine MOF, both Pt-decorated MOF nanocomposites exhibit significantly improved yet distinctly different hydrogen-production activities, highlighting that the photocatalytic efficiency strongly correlates with the Pt location relative to the MOF. The Pt@UiO-66-NH2 greatly shortens the electron-transport distance, which favors the electron–hole separation and thereby yields much higher efficiency than Pt/UiO-66-NH2. The involved mechanism has been further unveiled by means of ultrafast transient absorption and photoluminescence spectroscopy.

Efficient synthesis of monolayer carbon nitride 2D nanosheet with tunable concentration and enhanced visible-light photocatalytic activities

Abstract: A versatile and scalable mixed solvent strategy was developed to prepare monolayer C3N4 nanosheets with tunable concentration for the first time. This approach could also be used to prepare other 2D nanosheets from their layered materials (such as MoS2, BN, WS2 etc.). The structural features and intrinsic semiconductor properties of the as-prepared C3N4 nanosheets have been investigated in detailed. The photocatalytic activities were evaluated by photocatalytic oxidation of both benzyl alcohol and rhodamine B (RhB) under visible light irradiation. Results showed that the as-prepared monolayer C3N4 nanosheets with thickness of 0.4 nm still retained the structural features of g-C3N4 layer. The functionalities of C3N4 nanosheets well inherited from the layered parent counterpart. Furthermore, due to the exceptionally high 2D anisotropy, C3N4 nanosheets showed the distinctive physicochemical properties and unique electronic structures, such as high surface area, lower surface defects, stronger reduction ability of the photogenerated electrons, increased photoelectric response, and promoted the charge-carrier migration and separation. All of these favorable factors co-contributed to the greatly improved photocatalytic activities over C3N4 nanosheets compared with those of its bulk counterpart.