Photocatalytic activity and photocorrosion of atomic layer deposited ZnO ultrathin films for the degradation of methylene blue

Abstract

ZnO ultrathin films with varied thicknesses of 7-70 nm were prepared at 200 °C on Si and fused quartz substrates by atomic layer deposition (ALD). The impact of film thickness and annealing temperature on the crystallinity, morphology, optical bandgap, and photocatalytic properties of ZnO in the degradation of methylene blue (MB) dye under UV light irradiation (λ = 365 nm) has been investigated deeply. The as-deposited 28 nm thick ZnO ultrathin film exhibits highest photocatalytic activity, ascribed to the smallest band gap of 3.21 eV and proper thickness. The photocorrosion effect of ALD ZnO ultrathin films during photocatalytic process is observed. The presence of MB significantly accelerates the dissolution of ZnO ultrathin films. The possible photoetching mechanism of ZnO in MB solution is proposed.

Meso-porous ZnO nano-triangles @ graphitic-C 3 N 4 nano-foils: Fabrication and Recyclable photocatalytic activity

“…The intensity of Zn 2p and O 1s peaks are decreased after photoreaction. The XPS results are in good agreement with the recent work reported by Cao et al [51]. It is also revealed that bare ZnO-nt suffers more by photo-corrosion than ZnO-nt@g-C 3 N 4 (20%).…”

Controlled growth of ZnO nanorod arrays via wet chemical route for NO2 gas sensor applications

“…Fig. 4(b) shows high-resolution XPS spectra for the ZnO samples, revealing two Zn 2p 3/2 and Zn 2p 1/2 peaks at 1021.88 eV and 1044.81 eV with a better symmetry, corresponding to the spin-orbit split in the Zn 2p spectra [21]. The peak separation was of 23 eV, which is in good agreement with the energy splitting of ZnO.…”

Novel synthesis of ZnO/PMMA nanocomposites for photocatalytic applications

“…It is worth noting that the photo-corrosion of ZnO during the photocatalytic process is a commonly observed phenomenon45. As a consequence, the photo-stability of the ZnO in the composite during the photocatalytic process was tested, by repeating the photo-degradation measurements seven times.…”