Hollow Submicrospherical Ni/Co-Promoted CaO/Ca<sub>12</sub>Al<sub>14</sub>O<sub>33</sub> for H<sub>2</sub> Production from Sorption-Enhanced Water–Gas Shift with In Situ CO<sub>2</sub> Conversion via CH<sub>4</sub> Reforming of CaCO<sub>3</sub>
Chunxiao Zhang, Yingjie Li, Yumeng Deng, Wenqiang Liu, Kuihua Han, Yuzhuo Wang, Zirui He, Jun Jie Wu
Abstract
CaO sorbent/catalyst bifunctional materials are promising for CO 2 capture in sorption-enhanced H 2 production such as sorption-enhanced water–gas shift. For simultaneous H 2 production with CO 2 in situ capture and utilization, the integrated process of sorption-enhanced water–gas shift and in situ CO 2 conversion by CH 4 reforming of CaCO 3 was proposed. This work focused on the tailored design of a CaO sorbent/catalyst bifunctional material for both efficient H 2 production and in situ CO 2 conversion in this integrated process. The template-assisted strategy of hydrothermal carbonization followed by self-reduction and template removal via steam gasification was first proposed to obtain the hollow submicrospherical Ni/Co-promoted CaO/Ca 12 Al 14 O 33 . The as-synthesized material exhibits high and stable H 2 production, CO 2 capture, and in situ CO 2 conversion performance in the integrated process due to the unique hollow submicrospherical structure and enhanced catalytic activity. Ni–Co interaction boosts oxygen vacancy and Ni–Co alloy, which are the active catalytic sites for the water–gas shift and CH 4 –CaCO 3 reactions. Moreover, the oxygen vacancy-mediated mechanism on CH 4 reforming of CaCO 3 over the hollow submicrospherical Ni/Co-promoted CaO/Ca 12 Al 14 O 33 is confirmed. After 20 cycles, CO conversion from sorption-enhanced water–gas shift using the as-synthesized material retains 97.0%, accompanied by high CH 4 conversion of 95.1% and the H 2 /CO molar ratio close to unity from CH 4 reforming of CaCO 3 .