Abstract
Although Ni-Ca-based dual functional materials (DFMs) have been examined for CO(2) capture and reduction with H(2) (CCR) for the synthesis of CH(4), their performance has generally been investigated using single reactors in an oxygen-free environment. In addition, continuous CCR operations have scarcely been investigated. In this study, continuous CCR for the production of CH(4) was investigated using a double reactor system over Al(2)O(3)-supported Ni-Ca DFMs in the presence of O(2). We found that a high Ca loading (Ni(10)-Ca(30)/Al(2)O(3), 10 wt% Ni, and 30 wt% CaO) was necessary for reaction efficiency under isothermal conditions at 450 °C. The optimized DFM exhibited an excellent performance (46% CO(2) conversion, 45% CH(4) yield, and 97% CH(4) selectivity, respectively) and good stability over 24 h. The structure and CCR activity of Ni(10)-Ca(30)/Al(2)O(3) were studied using X-ray diffraction (XRD), scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectrometry (EDS), temperature-programmed desorption (TPD), and temperature-programmed surface reaction (TPSR) techniques.