Synthesis and Characterization of La_xBa_1-xFe_yAl_1-yO₃, Perovskite Oxides, for CO₂ to CO Conversion

Author

Hanzhong Shi, University of South FloridaFollow

Graduation Year

2019

Document Type

Thesis

Degree

M.S.M.S.E.

Degree Name

MS in Materials Science and Engineering (M.S.M.S.E)

Degree Granting Department

Chemical Engineering

Major Professor

Venkat Bhethanabotla, Ph.D.

Co-Major Professor

John Kuhn, Ph.D.

Committee Member

Scott Campbell, Ph.D.

Keywords

catalyst, CO2 recycling, greenhouse gas, low temperature conversion, reverse water-gas shift chemical looping

Abstract

As the greenhouse gas effect becomes more serious, it is important to find an effective way to reduce carbon dioxide emissions and/or convert it to value-added products. Based on the catalytic requirements, convert CO₂ to CO using perovskite-type oxides which are suitable for reverse water-gas shift chemical looping (RWGS-CL). The resulting carbon monoxide can be subsequently used for chemical energy storage in the form of hydrocarbon-based fuels and chemicals. This research focuses on the synthesis of the La_xBa_1-xFe_yAl_1-yO₃ perovskite-type oxides, which can form oxygen vacancies, or active sites for CO₂ conversion.

Multiple measurement methods were using for testing synthesized catalysts. Temperature-programmed reduction (TPR) and temperature-programmed oxidation (TPO) experiments were performed to identify reaction temperatures and redox properties of the materials. Surface areas were measured, and X-ray diffraction was utilized to identify the crystal structure.

La_0.25Ba_0.75FeO₃ and La_0.5Ba_0.5FeO₃ were showed an appreciate conversion property, and comparison was made between these two compositions. Results showed La_0.25Ba_0.75FeO₃ can converted more CO and La_0.5Ba_0.5FeO₃ made conversion in high stability.

Components of A site and B site element were analyzed based on characterization results, which showed lanthanum can increase catalyst stability, barium can increase CO yield, iron showed a better property as a B site component than aluminum.

In summary, this research based on serious CO₂ emission problem in the world, synthesized La_xBa_1-xFe_yAl_1-yO₃, nine perovskite oxide catalysts, to convert wasted CO₂ to CO. Comparison was made with other perovskite-type catalysts for RWGS-CL, the results showed the two samples were advantageous on lower conversion temperature of 500°C.

Scholar Commons Citation

Shi, Hanzhong, "Synthesis and Characterization of La_xBa_1-xFe_yAl_1-yO₃, Perovskite Oxides, for CO₂ to CO Conversion" (2019). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/8414