Surface oxygen vacancies enriched Pt/TiO2 synthesized with a defect migration strategy for superior photocatalytic activity

Qiu, Huan; Ma, Xujun; Sun, Caifeng; Zhao, Bin; Chen, Feng

doi:10.1016/j.apsusc.2019.145021

Cited by 43 publications

(32 citation statements)

References 51 publications

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“…As comparison, a much stronger peak intensity of O deficiency in AT-420 demonstrated a higher content of surface O V . Furthermore, the clear shift toward lower binding energy for the lattice O peak observed in sample AT-420 was due to the high-density surface oxygen vacancies [ 49 ]. Therefore, as shown in Figure 4 B–D, compared with P25 TiO 2 , an apparent blue shift (0.1 eV) in Ti 2p and O 1s spectra were observed, which confirmed the existence of surface defects of Ti 3+ and O V on the disordered surface.…”

Section: Resultsmentioning

confidence: 99%

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

Feng

et al. 2022

Nanomaterials

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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.

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Section: Resultsmentioning

confidence: 99%

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

Feng

et al. 2022

Nanomaterials

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“…Therefore, the presence of this narrow ESR peak in the case of the photocatalysts formed on sol–gel supports by H 2 treatment (not shown) is not surprising. In fact, several authors in the literature assume that the oxygen vacancies responsible for the sharp ESR signal at g ≈ 2.00 may influence the surface redox properties of the TiO 2 materials [ 74 , 75 , 76 , 77 , 78 ]. As such vacancies are detectable in the sol–gel supports even after preparation at 500 °C, but are missing from the P25 TiO 2 , their influence on the surface chemical properties can indeed explain some of the XPS observations, although microstructural differences as well as the always higher overall disorder of the sol–gel materials should also be considered.…”

Section: Resultsmentioning

confidence: 99%

Effect of the Microstructure of the Semiconductor Support on the Photocatalytic Performance of the Pt-PtOx/TiO2 Catalyst System

et al. 2021

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The influence of the semiconductor microstructure on the photocatalytic behavior of Pt-PtOx/TiO2 catalysts was studied by comparing the methanol-reforming performance of systems based on commercial P25 or TiO2 from sol–gel synthesis calcined at different temperatures. The Pt co-catalyst was deposited by incipient wetness and formed either by calcination or high-temperature H2 treatment. Structural features of the photocatalysts were established by X-ray powder diffraction (XRD), electron spin resonance (ESR), X-ray photoelectron spectroscopy (XPS), optical absorption, Raman spectroscopy and TEM measurements. In situ reduction of Pt during the photocatalytic reaction was generally observed. The P25-based samples showed the best H2 production, while the activity of all sol–gel-based samples was similar in spite of the varying microstructures resulting from the different preparation conditions. Accordingly, the sol–gel-based TiO2 has a fundamental structural feature interfering with its photocatalytic performance, which could not be improved by annealing in the 400–500 °C range even by scarifying specific surface area at higher temperatures.

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“…By comparison, the peak intensity of Ti-OH in AT-60 was much stronger than that of Ti mesh, indicating a higher concentration of hydroxyl groups in HA-TiO 2−x . Moreover, a clear negative shift in binding energy of Ti-OH peak was due to the rich amount of surface O V , which can accumulate sufficient electrons [41]. Figure 5E exhibited the differences of deconvoluted O 1s spectra, in which AT-60 showed the strongest intensity of the Ti-OH peak.…”

Section: Formation Of O V In Ha-tio 2−xmentioning

confidence: 97%

Hydrogenated Amorphous TiO2−x and Its High Visible Light Photoactivity

Feng

Yuan

et al. 2021

Nanomaterials

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Hydrogenated crystalline TiO2 with oxygen vacancy (OV) defect has been broadly investigated in recent years. Different from crystalline TiO2, hydrogenated amorphous TiO2−x for advanced photocatalytic applications is scarcely reported. In this work, we prepared hydrogenated amorphous TiO2−x (HA-TiO2−x) using a unique liquid plasma hydrogenation strategy, and demonstrated its highly visible-light photoactivity. Density functional theory combined with comprehensive analyses was to gain fundamental understanding of the correlation among the OV concentration, electronic band structure, photon capturing, reactive oxygen species (ROS) generation, and photocatalytic activity. One important finding was that the narrower the bandgap HA-TiO2−x possessed, the higher photocatalytic efficiency it exhibited. Given the narrow bandgap and extraordinary visible-light absorption, HA-TiO2−x showed excellent visible-light photodegradation in rhodamine B (98.7%), methylene blue (99.85%), and theophylline (99.87) within two hours, as well as long-term stability. The total organic carbon (TOC) removal rates of rhodamine B, methylene blue, and theophylline were measured to 55%, 61.8%, and 50.7%, respectively, which indicated that HA-TiO2−x exhibited high wastewater purification performance. This study provided a direct and effective hydrogenation method to produce reduced amorphous TiO2−x which has great potential in practical environmental remediation.

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Surface oxygen vacancies enriched Pt/TiO2 synthesized with a defect migration strategy for superior photocatalytic activity

Cited by 43 publications

References 51 publications

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

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

Effect of the Microstructure of the Semiconductor Support on the Photocatalytic Performance of the Pt-PtOx/TiO2 Catalyst System

Hydrogenated Amorphous TiO2−x and Its High Visible Light Photoactivity

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