Nor Shafiqah, Mohd Nasir (2019) Ethanol CO₂ reforming over Ce and La promoted Cu/A1₂O3 catalysts for syngas production. Masters thesis, Universiti Malaysia Pahang (Contributors, UNSPECIFIED: UNSPECIFIED).
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Ethanol CO₂ reforming over Ce and La promoted CuA1₂O3 catalysts.pdf - Accepted Version Download (376kB) | Preview |
Abstract
Ethanol CO2 reforming (ECR) is an eco-friendly and novel way for syngas production as it not only consumes bio-ethanol but also offers an additional benefit by utilizing the unwanted greenhouse gas (CO2). Nevertheless, the carbonaceous deposition during ECR process leads to deactivation of the catalyst. Hence, the aim of this thesis was to investigate the effect of CeO2 and La2O3 as promoters and promoter loading on the physicochemical properties of 10%Cu/Al2O3. 3%Ce- and 3%La-promoted 10%Cu/Al2O3 catalysts were synthesized via sequential incipient wetness impregnation approach meanwhile, unpromoted catalysts were prepared by incipient wetness impregnation technique. The catalysts were characterized using N2 physisorption (BET), temperatureprogrammed reduction (TPR), temperature programmed oxidation (TPO), X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. The processes were evaluated in stainless steel fixed-bed reactor at varying temperature from 948 to 1023 K and CO2:C2H5OH ratios of 2.5:1 to 1:2.5 under atmospheric pressure. The BET surface area of these catalysts was about 93.4 to 98.5 m2 g-1 whereas the calculated average CuO crystallite size declined from 32.4 to 27.4 nm with La2O3 and CeO2 additions because of the diluting effect. Promoter addition enhanced metal-support interaction as evidenced in H2-TPR analyses. The increasing H2 uptake with promoters during H2-TPR was indicative of enhancing degree for CuO → Cu0 reduction. Both reactant conversions increased substantially with rising temperature from 948-1023 K for all samples due to ECR endothermic nature. The increase in CO2 partial pressure from 20 to 50 kPa improved reactant conversions for all catalysts whilst the optimal C2H5OH partial pressure was observed at 40 kPa. The existence of concurrent endothermic ethanol dehydrogenation in ECR increased H2/CO ratio from 1.46 to 1.91 suitable for Fischer-Tropsch synthesis. XRD measurements of spent catalysts proved that Cu0 active phase was maintained during ECR and catalysts resisted to re-oxidation in CO2-containing feedstock. Although carbonaceous formation was detected on spent catalysts by XRD, TPO and HRTEM measurements, the significant decline in total carbon deposition from 40.04% to 27.55% was achieved by promoter addition in this order; La-doped < Ce-doped < unpromoted Cu/Al2O3. 3%La-Cu/Al2O3 is the best catalyst for this research with C2H5OH conversion (94.64%), CO2 conversion (73.21%), H2 yield (68.32%) and CO yield (32.06%) due to redox cycle ability, basic properties, possessed highest H2 consumption and smallest crystallite size.
| Item Type: | Thesis (Masters) |
|---|---|
| Additional Information: | Thesis (Master of Science) -- Universiti Malaysia Pahang – 2019, SV: DR. VO NGUYEN DAI VIET, NO. CD: 12381 |
| Uncontrolled Keywords: | Ethanol; syngas production |
| Subjects: | T Technology > TP Chemical technology |
| Faculty/Division: | Faculty of Chemical & Natural Resources Engineering Institute of Postgraduate Studies |
| Depositing User: | Mrs. Sufarini Mohd Sudin |
| Date Deposited: | 07 Dec 2021 14:16 |
| Last Modified: | 07 Dec 2021 14:22 |
| URI: | http://umpir.ump.edu.my/id/eprint/32606 |
| Download Statistic: | View Download Statistics |
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