Macro–meso-porous TiO₂, ZnO and ZnO–TiO₂-composite thick films. Properties and application to photocatalysis

Abstract

We report on a new and versatile method for preparing homogenous, crack-free and macro-meso-porous thick films of TiO 2 , ZnO and ZnO-TiO 2 composites using a single step coating procedure and fairly low annealing temperatures of a maximum of 400 1C. The method relies on an oxide nanopowder filler in an optimized precursor solution. The films are well adherent to the substrate, show homogeneously distributed open porosity, and are hydrophilic. The photocatalytic activity of these films was characterized using methyl orange as a model dye. We show that the TiO 2 films have better photocatalytic activity than ZnO and ZnO-TiO 2 composite films. The advantages of these composite films over particulate photocatalysts lie in their robustness and ease of application as no filtration is needed. Furthermore it is possible to apply them on suitable large area membranes.

In situ assembly of well-dispersed Au nanoparticles on TiO2/ZnO nanofibers: A three-way synergistic heterostructure with enhanced photocatalytic activity

“…A schematic for electron-hole separation and transportation at the TiO 2 /ZnO/Au NFs photocatalyst interface is shown in Scheme 1. In the photosynthetic system, there existed three ways to transferring the photoinduced electrons: (i) the electrons in the CB of TiO 2 are entrapped by Au NPs due to its high Schottky barriers at the metal-semiconductor interface, which reduces the recombination with holes [20], (ii) from ZnO to Au irreversibly based on the high Schottky barriers at the ZnO/Au interface [21], (iii) as both TiO 2 and ZnO showed n-type semiconducting behavior in the photoelectrochemical characterization, a good line-up for their band energies promoted the electron transferring from CB of ZnO to CB of TiO 2 as the CB of TiO 2 was lower than that of ZnO, while the holes in the VB of TiO 2 could be trapped in the VB of ZnO, leading to efficient charge separation [22]. As a result, the electrons were irreversibly inhabited in the surface of Au, while the holes were transferred to the surface of ZnO, thus leading to the high separation efficiency of the electron-hole pairs.…”

Effect of Ni doping on the structural, optical and photocatalytic activity of MoS2, prepared by Hydrothermal method

“…ZnO semiconductors have wide band gap, energetic under UV region of light and embrace just 5% of light [17]. Various researchers have reported the enrichment in photocatalytic performance through adjustment of hertrojunctions of ZnO with TiO 2 , Ag 2 O, Cu 2 O etc semiconductors [18][19][20][21]. Recently for photcatalysis applications, transition metal Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.…”

Photocatalytic Activity of Titania/Polydicyclopentadiene PolyHIPE Composites

“…Light harvesting efficiency could be enhanced by a better distribution of photon energy as a result of increased light transfer through the macroporous channels. Moreover, structure‐in‐structure arrangements such as an interconnected porous network and accessible pore‐walls allow the control of molecular transport and minimize the pressure drop . Within this frame, template synthesis is a promising technique for the preparation of hierarchically porous photocatalysts with interconnected pores in the form of monoliths, membranes, or microspheres.…”