Ni modified ZSM-5 promoted syngas production in chemical looping via the structural regulation of Ni particles under redox conditions

Abstract

Chemical looping reforming of CH4 coupled with CO2 reduction stands out as a promising method for the syngas production. In this process, it is significant to design the oxygen carrier with high reactivity and stability. In this work, a highly efficient oxygen carrier is obtained by physically mixing Metal-modified ZSM-5 with LaFe0.85Ni0.15O3 (LFN). The physical and chemical properties of the oxygen carriers are characterized by XRD, Raman, XPS, BET, TEM, NH3-TPD, CO2-TPD and CH4-TPD techniques. It is noted that mesoporous structures are formed over the Ni modified ZSM-5, due to that part of Ni elements replace Al in the silicaluminate framework. The structure change of the ZSM-5 promotes the gas adsorption capacity. CH4 and CO2 cannot be adsorbed on the surface of ZSM-5, while Ni-modified ZSM-5 enhances the adsorption capacity for CO2 to a large degree. Moreover, Ni species are acted as active sites to facilitate the activation of CH4 and CO2 during the redox process. The aggregation-redispersion of Ni particles during the reduction-oxidation process inhibits the deactivation of Ni particles, which improves the stability of the oxygen carrier. Among all the obtained samples, LFN/10 wt% Ni-ZSM-5 exhibits the highest yields of syngas (8.38 mmol g−1) and CO (2.42 mmol g−1).