CO2 Conversion via Low-Temperature RWGS Enabled by Multicomponent Catalysts: Could Transition Metals Outperform Pt?

Abstract

In the context of CO₂ valorisation, the reverse water–gas shift reaction (RWGS) is gathering momentum since it represents a direct route for CO₂ reduction to CO. The endothermic nature of the reaction posses a challenge when it comes to process energy demand making necessary the design of effective low-temperature RWGS catalysts. Herein, multicomponent Cs-promoted Cu, Ni and Pt catalysts supported on TiO₂ have been studied in the low-temperature RWGS. Cs resulted an efficient promoter affecting the redox properties of the different catalysts and favouring a strong metal-support interaction effect thus modulating the catalytic behaviour of the different systems. Positive impact of Cs is shown over the different catalysts and overall, it greatly benefits CO selectivity. For instance, Cs incorporation over Ni/TiO₂ catalysts increased CO selectivity from 0 to almost 50%. Pt-based catalysts present the best activity/selectivity balance although CuCs/TiO₂ catalyst present comparable catalytic activity to Pt-studied systems reaching commendable activity and CO selectivity levels, being an economically appealing alternative for this process.