Thermochemical activation of CO2 into syngas over ceria-supported niobium oxide catalyst: An integrated experimental-DFT study

Thermochemical splitting of a mixture of CO2 and water into syngas (and methane) remains a viable approach toward an industrial-scale treatment of CO2 emission. However, most deployed catalysts encompass expensive metallic ingredients such as Pd or Pt. In an integrated experimental-modelling approach, this work reports a high conversion of CO2 over alternative and cost-effective configurations. Ceria-based catalysts are proven to be effective in numerous catalytic processes owing to the facile switch in the Ce redox cycle. Evolution of H2 and CO from thermochemical splitting of water and carbon dioxide is an important process in the production of syngas and in fuel cell applications. In this study, NbOx ceria catalysts are prepared, characterized, and applied for production of syngas via the thermochemical splitting of CO2 and gaseous water. It was observed that presence of Nb in the ceria matrix up to 12 wt%, increases the reaction yield at higher temperature (up to 79% CO2 conversion with 80% selectivity to syngas at 600 ºC). Moreover, the catalytic reaction was found to display a higher selectivity towards syngas over the ceria supported catalysts. The attained conversion is higher than other ceria-supported catalysts such as Rh-CeO2, CeO2-ZrO2, and V2O5-CeO2. Mapped-out reaction pathways by DFT calculations portray accessible routes into syngas. Results provided herein should be useful to optimize a continuous process for the valorization of CO2 into syngas over relatively affordable a catalytic formulation.