Development of highly efficient nickel-doped zeolitic imidazole framework (ZIF-67) based catalyst for methanation reaction
The conversion of CO2 to synthetic natural gas via methanation reaction is gaining popularity due to its potential to solve long-term energy storage challenges and reduce CO2 emissions. Developing a highly efficient catalyst that can actively function under low reaction temperatures is crucial fo...
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| Format: | Thesis |
| Language: | English |
| Published: |
2023
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/118643/ http://psasir.upm.edu.my/id/eprint/118643/1/118643.pdf |
| Summary: | The conversion of CO2 to synthetic natural gas via methanation reaction is gaining
popularity due to its potential to solve long-term energy storage challenges and reduce
CO2 emissions. Developing a highly efficient catalyst that can actively function under
low reaction temperatures is crucial for the methanation reaction’s sustainability and for
making CO2 capture more affordable. Utilizing highly porous metal-organic framework
(MOF) materials such as ZIF-67 as catalyst support with added Ni would be an
interesting endeavor to achieve good dispersion and resist agglomeration of dopants
during methanation reaction. Therefore, ZIF-67 was prepared using 2-methylimidazole
and cobalt nitrates, and the obtained ZIF-67 solid was activated under a vacuum oven
overnight at 80 °C. Nickel dopant was incorporated onto ZIF-67 in the range of 1-12
wt% via wet-impregnation method, and the catalyst precursor was calcined at 350 °C for
4h under N2 flow. The prepared catalysts were characterized using Brunauer-Emmett-
Teller (BET), X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Fouriertransform
infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS),
Temperature-programmed desorption of carbon dioxide (TPD-CO2), Temperatureprogrammed
reduction (TPR), and High-resolution transmission electron microscopy
(HRTEM). Prior to the methanation reaction, 0.05g of catalyst was loaded into a fixed
tubular reactor and reduced in situ under (5% H2/balanced Ar) flow at 350 °C for
3h. Subsequently, the flow is switched to reactant gas for catalytic testing at a
predetermined reaction temperature. Preliminary catalytic methanation reaction was
carried out at a temperature of 400°C, with a flow rate of 108,000 mL.g-1.h-1 and
feedstock gas (H2/CO2) ratio of 4:1. The physicochemical characterization of the
prepared catalysts exhibit very high surface area and porosity along with evenly
distributed Ni dopants over ZIF-67 support. The catalysts were found to be active in
CO2 conversion, whereby the presence of Ni significantly influences the product
selectivity of the reaction. Based on the catalytic screening results, 8wt% Ni/ZIF-
67 catalyst was deemed the most active among the other prepared catalysts in the
methanation reaction, with a moderate CO2 conversion of 56% followed by selectivity
of 96% at a reaction temperature of 300°C. |
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