Ni/CaO-based dual-functional materials for calcium-looping CO2 capture and dry reforming of methane: Progress and challenges

Efficiently integrating CO2 capture and chemical conversion is an advanced strategy for decreasing CO2 emissions from various flue gases while achieving the potential release of CO2 For this purpose, calcium looping (CaL) for CO2 capture and dry reforming of methane (DRM) have been developed as potential methods because of its low cost, easy availability, high adsorption capacity and fast adsorption rate in CaL processes and value-added products in the DRM process. molecules.Moreover, two kinds of greenhouse gases (CO2 and CH4) can decrease at the same time, and the as-produced syngas (CO and H2) in the DRM process can be used as an ingredient of liquid fuels and valuable chemicals. However, CaO-based adsorbents for CaL processes still face high adsorption energy consumption, pore collapse, and sintering problems after many cycles, and several reactions often occur during DRM processes, such as methane decomposition and reverse water gas shift (RWGS), in which the initial activity is easily deactivated during the DRM reaction due to coke formation on the active Ni surface and aggregation of Ni-based catalysts. Fortunately, coupling CaL-DRM processes may alleviate the above problems during a temperature increase, which is considered an energy-effective in situ CO2 conversion process. Here, this work systemically describes the challenges and development of CaO-based adsorbents for CO2 capture, Ni-based catalysts for DRM processes, and Ni/CaO-based dual-functional materials (DFMs) for coupling CaL-DRM processes, which will provide new references for CO2 capture and chemical conversion.