Semiconductor−Metal Composite Nanostructures. To What Extent Do Metal Nanoparticles Improve the Photocatalytic Activity of TiO₂ Films?

Abstract

Noble metal particles of Au, Pt, and Ir were deposited on nanostructured TiO2 film using an electrophoretic approach. The nanocomposite films were characterized by UV-absorption and atomic force microscopy (AFM). The deposition of tetraoctylammonium bromide (TOAB)-capped metal nanoparticles on TiO2 films improved the photocurrent generation and induced a shift in the apparent flat band potential. The TiO2 films modified with TOAB-capped metal nanoparticles were less prone to the electron scavenging by the oxygen in solution. Improved photoelectrochemical performance of semiconductor−metal composite film is attributed to the shift in quasi-Fermi level of the composite to more negative potentials. Continuous irradiation of the composite films over a long period causes photocurrent to decrease as the semiconductor−metal interface undergoes chemical changes. The role of semiconductor−metal composite films in improving the rate of photocatalytic degradation of an azo dye is also discussed.

A review on plasmonic metal⿿TiO2 composite for generation, trapping, storing and dynamic vectorial transfer of photogenerated electrons across the Schottky junction in a photocatalytic system

“…The concentration of the deposited Ag increases with the increase in the deposition time. The increased Ag amount would prevent or hinder the contact between TiO 2 and the pollutant MB molecule and it also decreases the number of photons absorbed [146]. Ag nanoparticles with Fermi level (E f ) located around 0.4 V are found to be good electron acceptors and act as efficient electron traps under UV irradiation [147].…”

Enhanced Photocatalytic Activity of Pure Anatase Tio2 and Pt-Tio2 Nanoparticles Synthesized by Green Microwave Assisted Route

“…Titanium dioxide (TiO 2 ) nanoparticles have been intensively studied as catalyst for the photodegradation of organic compounds due to their unique physical and chemical properties [1][2][3] . Their photocatalytic performance is greatly determined by the particle's crystal phase, crystallinity, phase stability, size and surface chemical properties that largely depend on their synthetic route 4 .…”

Preparation of Au-Bi2O3Nanocomposite by Anodic Electrodeposition Combined with Galvanic Replacement

“…9 In addition to improved visible light absorption, the noble metal can act as a sink for the photogenerated electrons, thus improving charge separation. 9 This approach has been employed for wide-bandgap semiconductors such as TiO 2 and ZnO.…”

“…9 In addition to improved visible light absorption, the noble metal can act as a sink for the photogenerated electrons, thus improving charge separation. 9 This approach has been employed for wide-bandgap semiconductors such as TiO 2 and ZnO. 9,12 Unlike TiO 2 and ZnO however, the photocatalytic activity of Bi 2 O 3 decorated with noble metals has not been extensively investigated.…”