Hydrogenated Amorphous Titania with Engineered Surface Oxygen Vacancy for Efficient Formaldehyde and Dye Removals under Visible-Light Irradiation

Abstract

Hydrogenated crystalized TiO2−x with oxygen vacant (OV) doping has attracted considerable attraction, owing to its impressive photoactivity. However, amorphous TiO2, as a common allotrope of titania, is ignored as a hydrogenated templet. In this work, hydrogenated amorphous TiO2−x (HAm-TiO2−x) with engineered surface OV and high surface area (176.7 cm2 g−1) was first prepared using a unique liquid plasma hydrogenation strategy. In HAm-TiO2−x, we found that OV was energetically retained in the subsurface region; in particular, the subsurface OV-induced energy level preferred to remain under the conduction band (0.5 eV) to form a conduction band tail and deep trap states, resulting in a narrow bandgap (2.36 eV). With the benefits of abundant light absorption and efficient photocarrier transportation, HAm-TiO2−x coated glass has demonstrated superior visible-light-driven self-cleaning performances. To investigate its formaldehyde photodegradation under harsh indoor conditions, HAm-TiO2−x was used to decompose low-concentration formaldehyde (~0.6 ppm) with weak-visible light (λ = 600 nm, power density = 0.136 mW/cm2). Thus, HAm-TiO2−x achieved high quantum efficiency of 3 × 10−6 molecules/photon and photoactivity of 92.6%. The adsorption capabilities of O2 (−1.42 eV) and HCHO (−1.58 eV) in HAm-TiO2−x are both largely promoted in the presence of subsurface OV. The surface reaction pathway and formaldehyde decomposition mechanism over HAm-TiO2−x were finally clarified. This work opened a promising way to fabricate hydrogenated amorphous photocatalysts, which could contribute to visible-light-driven photocatalytic environmental applications.

Synthesis of Ultrathin AuPt Alloy Porous Nanowires with Abundant Electrocatalytic Active Sites for Excellent Electrocatalysts

“…Based on the Vienna Ab initio Simulation Package (VASP), − generalized gradient approximation of Perdew–Burke–Ernzerhof functions were employed to carry out density functional theory (DFT) calculations. , To describe the interactions between ion cores and valence electrons, the projector augmented wave method was adopted, and the Kohn–Sham equations were expanded in a plane wave basis set with a cutoff energy of 400 eV. Brillouin zone sampling was performed by using a Monkhorst–Pack k -point grid .…”

Special Issue: State-of-the-Art Nanophotonic and Optical Nanomaterials in China

“…This Special Issue aims to provide an overview of the current advances in nanophotonic and optical nanomaterials in China and to prompt new interest in this field. The collected eight articles [1][2][3][4][5][6][7][8] highlight the latest progress in nanophotonics and materials science, including developments of novel nanomaterials and ingenious nanoscale designs. These contributions may unveil new opportunities to control light, provide effective ways to optimize targeted performances, and have important implications for novel photonic devices operating beyond the diffraction limit.…”

“…Finally, two studies are presented in this collection to highlight promising applications in photocatalysts and solar cells, respectively. Hydrogenated amorphous titania with engineered surface oxygen vacancy was successfully prepared by Feng et al based on the liquid plasma-induced hydrogenation strategy [7], which provided a promising way to fabricate hydrogenated amorphous photocatalysts and may facilitate visible-lightdriven photocatalytic environmental applications. Zhao et al implemented thin-film solar cells based on a selenized CuSbS 2 absorber [8], which resulted in increased efficiency of photovoltaic devices to meet the requirement in large-scale applications.…”