Oxygen vacancy induces self-doping effect and metalloid LSPR in non-stoichiometric tungsten suboxide synergistically contributing to the enhanced photoelectrocatalytic performance of WO_3−x/TiO_2−xheterojunction

Abstract

A WO3-x/TiO2-x nanotube array (NTA) heterojunction photoanode was strategically designed to improve photoelectrocatalytic (PEC) performance by establishing a synergistic vacancy-induced self-doping effect and localized surface plasmon resonance (LSPR) effect of metalloid non-stoichiometric tungsten suboxide. The WO3-x/TiO2-x NTA heterojunction photoanode was synthesized through a successive process of anodic oxidation to form TiO2 nanotube arrays, magnetron sputtering to deposit metalloid WO3-x, and post-hydrogen reduction to engender oxygen vacancy in TiO2-x as well as crystallization. On the merits of such a synergistic effect, WO3-x/TiO2-x shows higher light-harvesting ability, stronger photocurrent response, and resultant improved photoelectrocatalytic performance than the contrast of WO3-x/TiO2, WO3/TiO2 and TiO2, confirming the importance of oxygen vacancies in improving PEC performance. Theoretical calculation based on density functional theory was applied to investigate the electronic structural features of samples and reveal how the oxygen vacancy determines the optical property. The carrier density tuning mechanism and charge transfer model were considered to be associated with the synergistic effect of self-doping and metalloid LSPR effect in the WO3-x/TiO2-x NTA.

Ultrathin Molybdenum Carbide MXene with Fast Biodegradability for Highly Efficient Theory‐Oriented Photonic Tumor Hyperthermia

“…The states near Fermi energy could be ascribed to the hybridization between the d bands of Mo atom. The photoabsorptive spectrum could be simulated from the dielectric function, which was analyzed by using the density functional theory method, and then the optical absorption coefficients were obtained . Notably, the simulated optical absorption spectrum acquired on Mo 2 C exhibits a wide and strong spectral absorption extending from NIR I to II biological window, peculiarly in the region of NIR II, which offers promising potential for the biomedical application of efficient photothermal conversion (Figure h).…”

Photoelectrocatalytic Hydrogen Production Using a TiO2/WO3 Bilayer Photocatalyst in the Presence of Ethanol as a Fuel

“…On the contrary, deposition of titania on the top of the WO3 film may result in the passivation of surface defects of the latter, and this would limit charge recombination sites. Passivation of surface defects has been observed and recorded in TiO2/WO3 and other semiconductor combinations [24][25][26][27][28][29][30]. In addition, titania films are more stable than WO3 films; therefore, the top titania layer provided protection against aggressive electrolytes.…”

Photocatalysis-mediated drug-free sustainable cancer therapy using nanocatalyst

“…2e), determining the non-stoichiometric ratio of W:O = 1:2.41. So many oxygen vacancies in SnS 1.68 -WO 2.41 nanoplates would greatly favor the enhancement of LSPR [22][23][24] . In addition, SnS 1.68 -WO 2.41 nanoplates were conjugated with trithiolterminated poly-(methacrylic acid) (PTMP-PMAA) by a coordination method to enhance their aqueous dispersion 25 .…”