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Oxygen defect boosted photocatalytic hydrogen evolution from hydrogen sulfide over active {0 0 1} facet in anatase TiO2
- Source :
- Applied Surface Science. 517:146198
- Publication Year :
- 2020
- Publisher :
- Elsevier BV, 2020.
-
Abstract
- In this work, the oxygen defect strategy was conducted to promote photo-splitting H2S into hydrogen (H2) on the typical anatase TiO2 with active {0 0 1} facet for the first time. Density functional theory (DFT) calculation results illustrate that surface oxygen vacancy can efficiently facilitate the electron transition across the forbidden band and enhance the surface adsorption ability with more negative adsorption energies of −0.82 to −2.85 eV for H2S and its fragments than that of 0.24 to −0.90 eV on the perfect surface. Importantly, the energy barrier is reduced by 1.58 eV in maximum along the reaction paths on the defected surface, and the changes of rate-determining step lead to H2 as the final product. In addition, the time-resolved fluorescence tests, photocurrent measurements and electrochemical impedance spectroscopy demonstrate that the oxygen vacancies can effectively separate photo-generated electron-hole pairs. As a result, the photocatalytic activities of H2 evolution from H2S on TiO2 {0 0 1} doped with oxygen vacancies have been significantly enhanced from 21.44 μmol g−1 h−1 to 95.25 μmol g−1 h−1. This enhanced photoactivity is due to the low recombination of photo-generated carriers, the favorable surface adsorption and reaction activity induced by oxygen vacancies.
- Subjects :
- Photocurrent
Anatase
Materials science
Hydrogen
Doping
General Physics and Astronomy
chemistry.chemical_element
02 engineering and technology
Surfaces and Interfaces
General Chemistry
010402 general chemistry
021001 nanoscience & nanotechnology
Condensed Matter Physics
Photochemistry
01 natural sciences
Oxygen
0104 chemical sciences
Surfaces, Coatings and Films
Dielectric spectroscopy
Adsorption
chemistry
Vacancy defect
0210 nano-technology
Subjects
Details
- ISSN :
- 01694332
- Volume :
- 517
- Database :
- OpenAIRE
- Journal :
- Applied Surface Science
- Accession number :
- edsair.doi...........1866f4a781624e16b626da6332c1d193