TY - JOUR
T1 - Energetics of CO2and H2O adsorption on alkaline earth metal doped TiO2
AU - Da Silva, Andre Luiz
AU - Wu, Lili
AU - Caliman, Lorena Batista
AU - Castro, Ricardo H.R.
AU - Navrotsky, Alexandra
AU - Gouvêa, Douglas
N1 - Funding Information:
D. G. would like to thank the financial support from FAPESP (proc. 2013/23209-2 and 2015/50443-1), the CNPq (proc. 4393352/2016-9) and LCT (Technologic characterization laboratory, USP, Poli, PMI). A. L. D. acknowledges the support of the RCGI Research Centre for Gas Innovation, hosted by the University of São Paulo and sponsored by FAPESP (grant 2014/50279-4) and Shell Brasil. RC thanks DMR Ceramics 1609781. A. N. acknowledges the U.S. Department of Energy Office of Basic Energy Sciences, grant DE-FG02-03ER46053, for support of the Peter A. Rock Thermochemistry Laboratory at UC Davis where the calorimetric experiments were performed.
Publisher Copyright:
© 2020 the Owner Societies.
PY - 2020/7/21
Y1 - 2020/7/21
N2 - The process of CO2 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 CO2 and H2O adsorption on TiO2 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 TiO2 surface affinity to CO2 and H2O, TiO2 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 TiO2 nanoparticles, both CO2 and subsequent H2O adsorption amounts could be increased. CO2 adsorbs in two different manners, forming carbonates which can be removed at temperatures lower than 700 °C, and a more stable linear adsorption that remains even at 700 °C. Additionally to the surface energetic effects, doping also increased specific surface area, resulting in further improvement in net gas adsorption.
AB - The process of CO2 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 CO2 and H2O adsorption on TiO2 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 TiO2 surface affinity to CO2 and H2O, TiO2 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 TiO2 nanoparticles, both CO2 and subsequent H2O adsorption amounts could be increased. CO2 adsorbs in two different manners, forming carbonates which can be removed at temperatures lower than 700 °C, and a more stable linear adsorption that remains even at 700 °C. Additionally to the surface energetic effects, doping also increased specific surface area, resulting in further improvement in net gas adsorption.
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U2 - 10.1039/d0cp01787f
DO - 10.1039/d0cp01787f
M3 - Article
C2 - 32613967
AN - SCOPUS:85088277043
SN - 1463-9076
VL - 22
SP - 15600
EP - 15607
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 27
ER -