Rb-Ni/Al2O3 as dual functional material for continuous CO2 capture and selective hydrogenation to CO

Abstract

Ni-based dual-functional materials (DFMs) have been widely investigated for CO2 capture and reduction with H2 (CCR). However, controlling the selectivity of CO2 hydrogenation to CH4 or CO is a fundamental challenge. Most Ni-based DFMs favor the selectivity of CH4 over CO, although CO is more desirable than CH4 from a chemical-synthesis perspective. In this study, Rb-promoted Ni nanoparticles on Al2O3, Rb-Ni/Al2O3, are developed as an effective DFM for selective CO production through CCR with a CO2 conversion of 68% and a CO selectivity of 97% under isothermal conditions at 450 °C in the mixture of O2 during CO2 capture process. The developed Rb-Ni/Al2O3 is applicable to continuous CCR using double reactor system. The roles of Rb and Ni in CCR over Rb-Ni/Al2O3 for CO formation are also discussed based on temperature-programmed surface reactions and in situ spectroscopic studies.