Photocatalytic hydrogenation of propyne with water on small-particle titania: size quantization effects and reaction intermediates

Abstract

of supported Pt metal particles.21 Fast reduction rates in general lead to the formation of the more open Pt(110)-and Pt( 100)-like crystallographic faces. These open faces tend to be rougher and have a larger number of surface defects (steps and other imperfections). Slow reduction rates, on the other hand, favor the formation of smoother Pt(l 1 l)-like faces having fewer defect sites. ConclusionsThe following conclusions emerge from this study:(1) Variations in the nature of the adsorbed phase of NO depend on surface structure rather than on Pt dispersion.(2) NO is adsorbed on Pt/Si02 to give three distinct surface species. These include linearly adsorbed NO, bridge-bonded NO, and vibrationally coupled NO.(3) The collapse of band A occurs primarily on a smooth Pt surface due to the formation of this vibrationally coupled NO. Pretreatment in H2 promotes the formation of vibrationally coupled NO while pretreatment in 02 hinders it.

Growth of TiO2 nanotube arrays with simultaneous Au nanoparticles impregnation: photocatalysts for hydrogen production

“…Since UV light only accounts for about 5% of the solar radiation that reaches Earth's surface, the inability to utilize visible light limits the efficiency of solar photocatalytic hydrogen generation. Thus, different strategies have been adopted in order to improve this efficiency, including: i) varying the sizes of the nanoparticles, 10 ii) doping with metal/non-metal ions, 11 iii) coupling the titanium dioxide with low band gap semiconductors, 12 and iv) supporting metallic/metal oxide nanoparticles on the oxide surface to promote electron and hole transfer reactions at the TiO 2 /substrate interface. 13,14 In addition, it is desirable to produce TiO 2 structures composed mainly of the anatase phase, because it has higher catalytic activity than the rutile phase.…”

Phase Formation during Deposition of TiO<SUB>2</SUB> Coatings through High Velocity Oxy-Fuel Spraying

“…[1][2][3][4][5][6][7][8][9][10][11] The performance of TiO 2 coating is influenced by its microstructures including crystalline structure. For example, the photocatalytic performance of TiO 2 coating is significantly influenced by its phase structure.…”

“…It was reported that TiO 2 in anatase phase presents a higher photocatalytic activity than that in rutile phase. [7][8][9][10] Therefore, the controlling of the crystalline structure of TiO 2 coating through processing conditions is of essential importance to control the property and performance of TiO 2 deposits.…”

“…[1][2][3][4][7][8][9][10][11][12][13][14][15][16] Among these methods thermal spraying is characterized as a flexible and efficient process which has been widely used to deposit both metallic and nonmetallic coatings. TiO 2 coatings deposited through flame spraying and plasma spraying consist of rutile phase and a fraction of anatase phase.…”

A study of photodegradation of arylazo pyridone dyes

“…Kao rezultat toga, redoks potencijal fotostvorenih elektrona i šupljina se povećava (povećava se njihova oksidaciona i redukciona moć) i katalitička reakcija se razlikuje od fotoelektrohemijske reakcije kod TiO 2 čistih prahova [159]. Sa druge strane, povećanje potencijala smanjuje apsorpciju svetlosti u bliskoj UV oblasti.…”