Ba-addition induced enhanced surface reducibility of SrTiO3: implications on catalytic aspects.
Nanoscale Adv
; 1(12): 4938-4946, 2019 Dec 03.
Article
in En
| MEDLINE
| ID: mdl-36133134
ABSTRACT
Surface reducibility engineering is one of the vital tools to enhance the catalytic activity of materials. A heavy redox treatment can be utilized to affect the structure and surface of catalytic materials. Here, we choose SrTiO3 (STO) with a cubic perovskite structure as a system to induce oxygen vacancies by using nascent hydrogen from NaBH4 leading to a heavily reduced version of SrTiO3 (RSTO). To further understand the surface reduction and its dependence on foreign-ion (Ba) incorporation into SrTiO3, Sr0.5Ba0.5TiO3 (SBTO) and BaTiO3 (BTO) are synthesized using a facile hydrothermal method. The reduced version of the pristine and mixed oxide shows distinct optical absorptions, indicating oxygen vacancy-mediated reducibility engineering. Detailed CO oxidation experiments suggest the order of activity over the as-prepared and reduced supports as STO > SBTO > BTO and RSBTO > RSTO > RBTO, respectively. The interesting observation of reversal of CO oxidation activity over STO and SBTO after reduction negates the assumption of a similar intensity of reduction on the surfaces of these oxide supports. The fundamental aspect of surface reducibility is addressed using temperature programmed reduction/oxidation (TPR/TPO) and XPS.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Nanoscale Adv
Year:
2019
Document type:
Article