Synthetic Ni-CaO-CeO2 dual function materials for integrated CO2 capture and conversion via reverse water-gas shift reaction

Integrated CO2 capture with reverse water gas shift (RWGS) reaction to produce syngas represents a promising technology to realize C1 recycling and utilization. Designing highly efficient Ni-CaO dual function materials (DFMs) is the key to achieve integrated CO2 capture and utilization (ICCU). In this work, Ni-CaO-CeO2 DFMs powders and pellets are prepared by the wet mixing, coprecipitation and sol-gel methods using acetate and nitrate precursors. Physicochemical properties and ICCU performance of the Ni-CaO-CeO2 DFMs depend on synthetic mode, precursor, and granulation process. NiCaCe-SG (A) and NiCaCe-SG (N) prepared by sol-gel method show excellent ICCU-RWGS performance due to the developed pore structures, enhanced surface ba-sicity, uniform Ni dispersion, minimized Ni grain size, abundant oxygen vacancies and reinforced reducibility. The NiCaCe-SG (A) sample prepared using acetate salts as precursors exhibits better ICCU-RWGS performance than the nitrate precursors-derived NiCaCe-SG (N) DFMs. Granulation adversely affects the CO2 capture ca-pacity, CO yield and working stability of the NiCaCe-SG (N) sample due to declined textural properties, weakened surface basicity and reducibility. NiCaCe-SG (A) represents an excellent DFMs candidate for ICCU-RWGS with high CO2 uptake and conversion rate of 15.34 mmol CO2/g and 92.4 %, great CO yield and CO selectivity of 5.97 mmol CO/g and 89.1 %, and good working stability (a low decay rate of 11.6 % in 10 cycles). These results have provided new insights into the rational design of high-performance DFMs for ICCU applications.