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

Abstract

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 basicity, 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 capacity, 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.