Synergetic modulation of surface alkali and oxygen vacancy over SrTiO3for the CO2photodissociation

Hua Xu; Chunlei Yan; Ruizhe Li; Lizhu Song; Shuxin Ouyang

doi:10.1088/1361-6528/ac38e8

Synergetic modulation of surface alkali and oxygen vacancy over SrTiO₃for the CO₂photodissociation

Nanotechnology. 2021 Nov 30;33(8). doi: 10.1088/1361-6528/ac38e8.

Authors

Hua Xu¹, Chunlei Yan², Ruizhe Li³, Lizhu Song², Shuxin Ouyang³

Affiliations

¹ School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, 206 Guanggu 1st Road, Wuhan 430205, People's Republic of China.
² TJU-NIMS International Collaboration Laboratory, School of Materials Science and Engineering, Tianjin University, 92 Weijin Road, Tianjin 300072, People's Republic of China.
³ College of Chemistry, Central China Normal University, 152 Luoyu Road, Wuhan 430079, People's Republic of China.

PMID: 34763329
DOI: 10.1088/1361-6528/ac38e8

Abstract

Photochemical conversion of CO₂into solar fuels is one of the promising strategies to reducing the CO₂emission and developing a sustainable carbon economy. For the more efficient utilization of solar spectrum, several approaches were adopted to pursue the visible-light-driven SrTiO₃. Herein, oxygen vacancy was introduced over the commercial SrTiO₃(SrTiO_3-x) via the NaBH₄thermal treatment, to extend the light absorption and promote the CO₂adsorption over SrTiO₃. Due to the mid-gap states resulted from the oxygen deficiency, combined with the intrinsic energy level of SrTiO₃, the SrTiO_3-xcatalyst exhibited excellent CO productivity (4.1 μmolˑg^-1ˑh^-1) and stability from the CO₂photodissociation under the visible-light irradiation (λ > 400 nm). Then, surface alkalization over SrTiO_3-x(OH-SrTiO_3-x) was carried out to further enhance the CO₂adsorption/activation over the surface base sites and provide the OH ions as hole acceptor, the surface alkali OH connected with Sr site of SrTiO₃could also weaken the Sr-O bonding thus facilitate the regeneration of surface oxygen vacancy under the light illumination, thus resulting in 1.5 times higher CO productivity additionally. This study demonstrates that the synergetic modulation of alkali OH and oxygen vacancy over SrTiO₃could largely promote the CO₂photodissociation activity.

Keywords: CO2 photodissociation; oxygen vacancy; strontium titanate; surface alkalization.