Selective Photocatalytic Oxidation of Aniline to Nitrosobenzene by Pt Nanoparticles Supported on TiO₂ under Visible Light Irradiation

Abstract

Visible light irradiation (λ > 450 nm) of Pt nanoparticles supported on Degussa P25 TiO 2 (Pt/P25 catalyst) promotes efficient and selective aerobic oxidation of aniline to nitrosobenzene. This is facilicated via the interband excitation of Pt atoms by visible light followed by the transfer of activated electrons to the TiO 2 conduction band. The positive charges formed on the Pt surface oxidize substrates, and the conduction band electrons reduce O 2 , promoting photocatalytic cycles. The high activity of Pt/P25 is due to the high electron density of Pt particles. They behave as Lewis base sites for reductive deprotonation of aniline, thus promoting efficient aniline oxidation. The Pt/P25 catalyst, when photoirradiated at a low temperature (∼283 K), suppresses subsequent condensation of aniline and the formed nitrosobenzene, successfully producing nitrosobenzene with a very high selectivity (90%).

Simple and Efficient System for Combined Solar Energy Harvesting and Reversible Hydrogen Storage

“…30 These results indicate that TiO 2 -support draws a significant effect on the catalytic performance through altering the electronic property of the loaded Pt species. 31 Nanosized Pt are visible-light-active species due to the intraband electron transitions, 32,33 whereas TiO 2 substrate can only absorb photons in the ultraviolet region. Therefore, the metallic Pt species in this study essentially act as both sensitizers to absorb resonant photons, and active sites to facilitate the dehydrogenation reaction.…”

Selective photocatalytic oxidation of aromatic alcohols in solar-irradiated aqueous suspensions of Pt, Au, Pd and Ag loaded TiO 2 catalysts

“…Although metal loaded TiO 2 photocatalysts have been widely used for degradation of harmful compounds under visible or solar irradiation [13][14][15][16], only a few investigations were carried out on their application in organic syntheses [17][18][19]. Shiraishi and co-workers investigated the photocatalytic synthesis of nitrosobenzene from aniline (90%) by using Pt loaded TiO 2 photocatalysts in toluene and under visible irradiation [19].…”

“…Shiraishi and co-workers investigated the photocatalytic synthesis of nitrosobenzene from aniline (90%) by using Pt loaded TiO 2 photocatalysts in toluene and under visible irradiation [19].…”

“…In order to increase TiO 2 activity and product selectivity, Meloaded TiO 2 catalysts (Me = Pt, Au, Pd and Ag) were home-prepared by photoreduction. Degussa P25 [24,25] and metal loaded Degussa P25 [19,[26][27][28] were deeply investigated by many studies. The specific aim of the present work is to evaluate the influence of the different metals loaded on TiO 2 , of the suspension pH and of the substituent groups of benzyl alcohol on the performance of the photocatalytic process.…”

Fabrication of hierarchical hollow silica/silver/silica/titania composite particles

“…hampers its photocatalytic activity. Consequently, the approaches of employing noble metal nanoparticles (NPs) have been pursued to overcome these obstacles [10][11][12][13]. The intention of introducing noble metal NPs is inhibiting e -/h ?…”