Energetics of CO(2)and H2O adsorption on alkaline earth metal doped TiO2

Author(s)

da Silva, Andre Luiz ^[1] ; Wu, Lili ^{[2, 3]} ; Caliman, Lorena Batista ^[1] ; Castro, Ricardo H. R. ^[4] ; Navrotsky, Alexandra ^{[5, 6]} ; Gouvea, Douglas ^[1]

Affiliation

^[1] Univ Sao Paulo, Dept Met & Mat Engn, Polytech Sch, BR-05508030 Sao Paulo - Brazil

^[2] Univ Calif Davis, NEAT ORU, One Shields Ave, Davis, CA 95616 - USA

^[3] Univ Calif Davis, Dept Chem, One Shields Ave, Davis, CA 95616 - USA

^[4] Univ Calif Davis, Dept Mat Sci & Engn, One Shields Ave, Davis, CA 95616 - USA

^[5] Arizona State Univ, Sch Mol Sci, Tempe, AZ 85287 - USA

^[6] Arizona State Univ, Ctr Mat Universe, Tempe, AZ 85287 - USA

• Document type: Journal article
• Source: Physical Chemistry Chemical Physics; v. 22, n. 27, p. 15600-15607, JUL 21 2020.
• Web of Science Citations: 5

Abstract

The process of CO(2)and H2O adsorption on the surface of nano-oxide semiconductors is important in the overall performance of artificial photosynthesis and other applications. In this study, we explored the thermodynamics of CO(2)and H2O adsorption on TiO(2)as a function of surface chemistry. We applied gas adsorption calorimetry to investigate the energetics of adsorption of those molecules on the surface of anatase nanoparticles. In an attempt to increase TiO(2)surface affinity to CO(2)and H2O, TiO(2)was doped with alkaline earth metals (MgO, CaO, SrO, and BaO) by manipulating the chemical synthesis. Adsorption studies using diffuse reflectance infrared spectroscopy at different temperatures indicate that due to the segregation of alkaline earth metals on the surface of TiO(2)nanoparticles, both CO(2)and subsequent H2O adsorption amounts could be increased. CO(2)adsorbs in two different manners, forming carbonates which can be removed at temperatures lower than 700 degrees C, and a more stable linear adsorption that remains even at 700 degrees C. Additionally to the surface energetic effects, doping also increased specific surface area, resulting in further improvement in net gas adsorption. (AU)

• FAPESP's process: 13/23209-2 - Ions segregation onto oxide nanopowders surfaces and the influence on the colloidal processing
• Grantee: Douglas Gouvêa
• Support Opportunities: Regular Research Grants
• FAPESP's process: 15/50443-1 - Interfaces in ceramic processing
• Grantee: Douglas Gouvêa
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/50279-4 - Brasil Research Centre for Gas Innovation
• Grantee: Julio Romano Meneghini
• Support Opportunities: Research Grants - Research Centers in Engineering Program