화학공학소재연구정보센터
International Journal of Hydrogen Energy, Vol.45, No.18, 10754-10763, 2020
Hierarchical porous spinel MFe2O4 (M=Fe, Zn, Ni and Co) nanoparticles: Facile synthesis approach and their superb stability and catalytic performance in Fischer-Tropsch synthesis
The environmental pollution problem and the dwindling in the crude oil resources have been driving considerable researches into alternative routes for the production of clean and low cost liquid fuels. Fischer-Tropsch synthesis (FTS) is a key-technology and a clean alternative for the production of valuable organic chemicals and high standard liquid fuels through the reaction of syngas (CO/H-2). In this study, one-pot hydrothermal reaction was adopted for the synthesis of robust MFe2O4 (M = Fe, Zn, Ni and Co) nanoparticles (NPs) with hierarchical porous-structured. The as-synthesized NPs and without the reported necessary pre-calcination step were appointed as robust catalysts in FTS at various reaction temperature (240-290 degrees C). The obtained catalytic results have demonstrated that CoFe2O4 NPs catalyst with its inversed spinel structure exhibited the optimum catalytic activity compared with the type of normal spinel structure of ZnFe2O4 catalyst. More precisely, CoFe2O4 NPs catalyst showed the best CO conversion ratio of 96% at 290 degrees C and the highest light-olefin (C-2-C-4) selectivity value of 63%. However, Fe3O4 NPs catalyst displayed the highest selectivity toward long chain hydrocarbon product (C5+) of 50 wt%, and the lowest CH4 selectivity value of 12% at 260 degrees C. Notably, the obtained results from X-ray diffraction and N-2-physisorption characterization for the spent ferrite catalysts demonstrated that the co-existence of the active sites of Hagg iron carbide (chi-Fe5C2) and metallic Co phases and along with the high surface area and pore diameter plays the key role for the obtained high catalytic activity in CoFe2O4 NPs. Moreover, the produced catalysts in this study exhibited good stability performance within maintained high catalytic activity for a period of at least 700 h of industrial-relevant FTS conditions. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.