Band-structure modulation of SrTiO3 by hydrogenation for enhanced photoactivity

Abstract

A systematic study on the band-structure modulation of SrTiO 3 (STO) by hydrogenation has been done by means of ultraviolet-visible (UV-vis) absorption, X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) and photoluminescence (PL). Hydrogenation of STO was performed by annealing STO in the forming gas of H 2 :N 2 (5 %:95 %) at elevated temperatures (mostly at 1000°C). It is found that electron transfer to the defect states within the band gap of STO due to hydrogenation brings to STO visible absorption, decrease in intrinsic PL intensity, Fermi level shift, elimination of the EPR signals, and finally, an enhancement of photocatalytic ability.

Effect of crystallization on the band structure and photoelectric property of SrTiO3 sol–gel derived thin film

“…Sun, T.et al [20] modulated the band structure of STO by hydrogenation to enhance the photocatalytic ability. Tan, H. et al [21] found that a controllable solid-state reaction of NaBH 4 and STO nanocrystals was a rational approach to fabricate oxygen vacancies on perovskite STO nanocrystals.…”

Modification of SrTiO3 surface by nitrogen ion bombardment for enhanced photocatalysis

“…Strontium titanate (SrTiO 3 or STO) is a typical perovskite [1], which has found wide applications in fields such as oxide electronics [2,3], environmental protection [4][5][6][7] and hydrogen production [8]. As a model ultraviolet (UV) photocatalyst similar to TiO 2 [9], STO absorbs only UV lights (its bandgap width is ∼3.20 eV) [10].…”

Enhancing photocatalysis in SrTiO3 by using Ag nanoparticles: A two-step excitation model for surface plasmon-enhanced photocatalysis

“…Photodecomposition experiments of MB were performed in a cuboid quartz vessel. 5,6 The STO to be evaluated was placed in the vessel with its surface normal to the incident light. 2.0 ml MB solution was added into the quartz vessel, which was aerated with an oxygen flow of 6 ml/min.…”

“…[1][2][3][4][5][6] As compared to TiO 2 , another typical UV photocatalyst with similar band gap width, [7][8][9][10][11] STO is more stable in crystallographic structure; hence, its photocatalytic activity that is crystallographic structure dependent is more stable. The band gap of a photocatalyst is required to straddle the redox potential of the reactant to be decomposed.…”

“…However, the UV portion is so low in solar emission spectrum [8][9][10][11] that various approaches have been developed to extend the response wavelength range to enhance the UV and visible photocatalytic activities of photocatalyst. Metal [1][2][3]12,13 or nonmetal ion dopings [4][5][6]14,15 have been studied via introducing intermediate levels within the band gap or narrowing the band gap width. Recently, a novel approach, i.e., surface plasmon (SP)-enhanced photocatalysis, has attracted considerable attention.…”