| The global warming issues caused by greenhouse gas(GHG) emissions have been drawn great attention.Hence,many investigations have been focused on the decreasing of the rate of GHG emissions.Fischer Tropsch Synthesis(F-T Synthesis) is one of the efficient techniques to obtain clean liquid fuels and to control the GHG emissions from fossil-fuels burning.How to improve the F-T reaction activity, reduce exhaust of CO2 and CH4 as well as energy consumption in the process of F-T synthesis are urgent problems for future industrialization.A key solution for solving the problem is to develop the F-T synthesis catalyst with high activity and high selectivity.In this paper,we constructed one Co(Ⅱ)-Ce(Ⅲ) polynuclear coordination polymer and a series of cobalt complexes with new space configuration.Two of the complexes were used as catalyst precursors for preparing alumina-supported catalysts for the F-T synthesis,and their catalytic performance were examined.The comprehensive evaluation of the catalysts such as F-T activity,selectivity of methane and carbon dioxide is presented and discussed.Detailed results are summarized as follows:1.Six coordination polymers have been obtained at room temperature or under hydrothermal conditions through assembling pyridine-2,3-dicarboxylic acid (2,3-H2pydc),pyridine-2,6-dicarboxylic acid(2,6-H2pydc),pyridine-3,4-dicarboxylic acid(3,4-H2pydc) and acetylacetone(acacH) respectively with cobalt or cerium salt or both.Furthermore,the structural characteristics were investigated.(1) Complex[Co2(2,3-Hpydc)6](3-carboxypyridine)2·6H2O;[Co(H2O)6][Co(2,3-Hpydc)3]; [Co(2,3-Hpydc)3]·3H2O were synthesized with pyridine-2,3-dicarboxylic acid and cobalt salts,and their 3D network structure was formed by hydrogen bonds andπ-πinteractions.(2) {[Ce2Co(2,6-pydc)4(H2O)8](H2O)7}n contained 1D infinite polymeric zigzag chains which were formed through bridging ligands of pyridine-2,6-dicarboxylate.(3) Complex Ce(acac)3(acacH)2 has a dimeric complex structure.The detailed analysis of crystal structure showed that the complex contained intramolecular H-bond and intermolecular H-bond formed through the neutral enol acetylacetone unidentate ligands.(4) Complex[Ce(3,4-pydc)2]·H2O was synthesized by mixing cerium nitrates with pyridine-3,4-dicaboxylic acid solution under hydrothermal condition.It extended in an infinite belt along a-axis and H-bonding interactions also contributed to the 3D network.2.A series of catalysts were prepared by impregnating different complex precursors onγ-Al2O3 support,and characterized by XRD,BET,and TPR techniques.The catalytic performance of these catalysts for F-T synthesis was tested,and their evaluation results are summarized as follows: (1) Using cobalt complex or cobalt(Ⅱ)-cerium(Ⅲ) heteronuclear coordination polymer as catalyst precursors resulted in a significant increase of cobalt dispersion in comparison with reference catalyst made from cobalt nitrate.(2) According to porous structure characteristics,the locating information of the macromolecular complexes with a six-member ring in the support could be estimated.3.The reforming experiment was performed with an assembly device for reforming of methane from carbon dioxide to syngas,and a production mode was simulated by coupling of the F-T reaction device with carbon dioxide reforming unit.
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