Tailoring the performance of Ni-CaO dual function materials for integrated CO2 capture and conversion by doping transition metal oxides

Abstract

Transition metal oxides (TMOs) doping is proposed as one effective strategy to improve CO2 capture and conversion performance of Ni-CaO dual function materials (DFMs). The effect of single and binary TMOs doping on structure–property-activity relationships of Ni-CaO DFMs for integrated CO2 capture and in-situ reverse water gas shift (RWGS) is investigated. ZrO2 doping enhances the surface basicity and reducibility of Ni-CaO DFMs for improved CO2 uptakes and reinforced catalytic activity. ZrO2 doping also endows Ni-CaO DFMs with improved working stability by forming CaZrO3 solid solution, which acts as physical barrier to retard the agglomeration and sintering of CaO and NiO species. Doping binary metal oxides of ZrO2-CeO2 further boosts the oxygen vacancy concentration in the DFMs for promoted CO2 activation and conversion and stabilized CO yield. The desired Ni-CaO-6ZrO2-6CeO2 DFMs shows a higher CO2 conversion of 72.1% and a lower decay rate of 12.0% for CO yield in consecutive cycles.