(32c) Enhanced CO2 Conversion to CO By Silica Supported Perovskite Oxides at Low Temperatures
World Congress on Particle Technology
8th World Congress on Particle Technology
Applications for Sustainable Energy & Environment
Energy Conversion Process Fundamentals III
Monday, April 23, 2018 - 4:30pm to 5:00pm
Repurposing of CO2 to valuable hydrocarbons is crucial for energy security and a balanced carbon cycle. Reverse water gas shift chemical looping (RWGS-CL) is capable of efficient CO2 to CO conversion at a low temperature of ~600 °C with unprecedented rates using the La0.75Sr0.25FeO3 (LSF) perovskite-type oxide amalgamated with silica. The LSF:SiO2 composite (25% LSF by mass) promotes a notable extent of oxygen vacancies in the active phase, a key parameter for CO2 conversion. In each of eight RWGS-CL cycles, CO generation yields of LSF:SiO2 surpass those of LSF alone by about 200%, producing 2.60 mmol CO gLSF-1 at a peak rate of 0.8 mmol CO gLSF-1 min-1. This significant improvement is concomitant with a decreased average LSF crystalline size retained at these low thermochemical reaction temperatures. Evidence of this enhancement points to wettability by silica, perovskite lattice strain induced by the support, and curtailed quantities of secondary phases that limit accessibility to active surfaces. In this contribution, an appropriate stable platform for improving earth abundancy in perovskite-based redox materials is demonstrated for potential industrial-scale, low temperature CO2 thermochemical conversion.