Abstract
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► The supported LaNiO3 perovskite catalysts on three mesoporous carrier with different structural features have been synthesized. ► In comparison with that of the bulk LaNiO3 perovskite, the supported samples showed much better catalytic performance. ► The relationships between catalytic behavior and property of catalysts have been established. ► The catalyst deactivation aspect has been discussed in detail.
The supported LaNiO3 perovskite catalysts on mesoporous carrier (LaNiO3/SBA-15, LaNiO3/MCM-41 and LaNiO3/SiO2) with different pore structures have been synthesized via filling the pores of mesoporous silica with citrate complex precursors of nickel and lanthanum, with further treatments. The catalysts were characterized by means of N2 physisorption, XRD, HRTEM+EDX, TPR, temperature-programmed hydrogenation (TPH) and TGA techniques, and their catalytic performances were measured in methane dry reforming with carbon dioxide to hydrogen and synthesis gas (syngas). The results of low-angle XRD, N2 physisorption and TEM analysis showed that LaNiO3 perovskite was formed inside the channels of mesoporous supports, and the introduction of LaNiO3 perovskite did not destroy the mesoporous structure of support. The pore structure had a substantial influence on the catalytic performance. LaNiO3/MCM-41 exhibited the higher initial catalytic activity, owing to the higher Ni dispersion, while LaNiO3/SBA-15 was superior to LaNiO3/MCM-41 in the long-term stability, which could be due to the stable silica matrix restricted the agglomeration of nickel species. The hexagonal mesopores of LaNiO3/SBA-15 were still kept intact after reaction, while the mesoporous structure in LaNiO3/MCM-41 was collapsed during the reaction, which resulted in metal particles aggregation to certain extent. For comparison, the carbon deposition was responsible for the remarkable decrease of catalytic activity over LaNiO3/SiO2 sample, evidenced by TGA and TPH results.