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

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.