Investigation of LaMnO₃ catalyst loaded on HZSM‐5 zeolite for CO catalytic oxidation

Abstract

Due to the large amounts of CO pollutant from iron ore sintering and vehicle emissions, the control of CO emission becomes more and more important for the environment. To control the emission of CO more effectively, the catalysts of LaMnO3 perovskite with HZSM‐5 zeolite as support were prepared by sol–gel method. The structure and catalytic activities of catalysts were characterized and analyzed. According to the results of X‐ray diffraction (XRD) and energy‐dispersive X‐ray spectroscopy (EDS), the LaMnO3 perovskite phase is successfully obtained in all the supported catalysts. The average particle sizes of supported catalysts are in the range of 15–38 μm. Compared with the perovskite catalysts loaded on other kinds of supports, LaMnO3 supported with HZSM‐5 has a larger specific surface area (SSA). The SSAs of supported catalysts with different loading amount are in the range of 190–300 m2/g. The HZSM‐5 support improves the catalytic activity of LaMnO3 catalyst by increasing the SSA. The activity of supported catalyst becomes higher when the loading amount increases from 20% to 60%. The catalyst with 60% perovskite loaded shows the best activity in CO catalytic oxidation. The CO conversion of 60LM/HZSM‐5 attains 50% and 90% at 172.7°C and 201.5°C, respectively. The activities of catalysts with 80% and 100% perovskite loaded decrease due to the accumulated pores formed by too much perovskite. The supported catalysts exhibit favorable activities in consecutive reaction cycles. It turns out that HZSM‐5 support is appropriate for the synthesis of active perovskite catalysts for CO oxidation.

Effect of seed on synthesis of binder‐free mordenite for dimethyl ether carbonylation

“…19,20 Numerous studies have also suggested many enhanced ways in the catalyst preparation stage or posttreatment stage in order to boost the catalytic activity and extend the catalyst life. [21][22][23][24] Post-treatments include methods such as selective dealumination, [25][26][27] metal modification, [28][29][30][31] and pyridine adsorption. 32,33 In the preparation stage, the mesoporous MOR or nano MOR were synthesized to shorten the diffusion path and overcome the diffusion resistance.…”

Investigation on the catalytic combustion of CO over LaMn1‐xCuxO3 promoted by acid treatment

“…12 LaMnO 3 is regarded as an efficient perovskite candidate for CO oxidation due to the multiple oxidation states of Mn 3+ /Mn 4+ , and the redox performance can be improved by partial substitution of B-site cations. 13 Qi et al 14 reported that the HZSM-5 supported the LaMnO 3 perovskite catalyst for CO catalytic oxidation. Tarjomannejad et al 15 prepared LaMn 1-x B x O 3 (B = Cu, Fe) perovskite for CO catalytic oxidation.…”