Aluminum enhances photochemical charge separation in strontium titanate nanocrystal photocatalysts for overall water splitting

Abstract

Photovoltage and overall water splitting activity of nanocrystals of aluminium-doped SrTiO3 correlate with aluminum content.

SrTiO3/Bi4Ti3O12 Nanoheterostructural Platelets Synthesized by Topotactic Epitaxy as Effective Noble-Metal-Free Photocatalysts for pH-Neutral Hydrogen Evolution

“…In terms of the H 2 production rate, our heterostructures demonstrate better performance than several other noble-metal-loaded photocatalysts ( Table S2, Supporting Information ). 19 − 22 , 39 − 41 Cycled measurements of the H 2 evolution revealed good repeatability and reusability of the nanoheterostructural SrTiO 3 /Bi 4 Ti 3 O 12 platelets ( Figure 6 and Figure S7 ). The stability of the H 2 evolution over the tested 24 h reaction time is similar to that reported for other SrTiO 3 -based photocatalysts ( Figure S7 ).…”

Electronic structure basis for enhanced overall water splitting photocatalysis with aluminum doped SrTiO3 in natural sunlight

“…1f insert). 37 Related states at 1.9-2.6 eV in non-doped SrTiO 3 have been previously attributed to a combination of self-trapped excitons, oxygen vacancies and oxygen vacancy complexes in the lattice and at the surface. 66,70 Similar states are also seen in the photoluminescence of TiO 2 .…”

“…S1, ESI †). 37 According to X-ray fluorescence measurements, Al-doped SrTiO 3 contains 1.2 atom% of Al. Based on the ion radius (54 pm for hexa-coordinated Al 3+ ), the Al 3+ ions mostly likely substitute Ti 4+ ions (61 pm) in the lattice.…”

“…This confirms earlier studies that the improved solar energy conversion ability of Al:SrTiO 3 is correlated with Al content. 27,31,37 In order to observe the electronic structure changes brought about by introduction of Al lattice, X-ray photoelectron spectra (XPS) were recorded for SrTiO 3 and for Al-doped SrTiO 3 . Fig.…”

“…These are responsible, however, for a weak 1.7-3.2 eV feature that is observed in optical absorption spectra of Al-doped SrTiO 3 . 37 Along with the suppression of the Ti 3+ states, reduced electron trapping and improved surface photovoltage are observed in electrochemical measurements and surface photovoltage spectra of Al-doped SrTiO 3 . These findings provide an experimental basis for the superior water splitting activity of Al-doped SrTiO 3 under UV and solar irradiation.…”