A study on methanol steam reforming to CO{sub 2} and H{sub 2} over the La{sub 2}CuO{sub 4} nanofiber catalyst
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117576, Republic of Singapore (Singapore)
The La{sub 2}CuO{sub 4} crystal nanofibers were prepared by using single-walled carbon nanotubes as templates under mild hydrothermal conditions. The steam reforming of methanol (SRM) to CO{sub 2} and H{sub 2} over such nanofiber catalysts was studied. At the low temperature of 150 deg. C and steam/methanol=1.3, methanol was completely (100%, 13.8 g/h g catalyst) converted to hydrogen and CO{sub 2} without the generation of CO. Within the 60 h catalyst lifespan test, methanol conversion was maintained at 98.6% (13.6 g/h g catalyst) and with 100% CO{sub 2} selectivity. In the meantime, for distinguishing the advantage of nanoscale catalyst, the La{sub 2}CuO{sub 4} bulk powder was prepared and tested for the SRM reaction for comparison. Compared with the La{sub 2}CuO{sub 4} nanofiber, the bulk powder La{sub 2}CuO{sub 4} showed worse catalytic activity for the SRM reaction. The 100% conversion of methanol was achieved at the temperature of 400 deg. C, with the products being H{sub 2} and CO{sub 2} together with CO. The catalytic activity in terms of methanol conversion dropped to 88.7% (12.2 g/h g catalyst) in 60 h. The reduction temperature for nanofiber La{sub 2}CuO{sub 4} was much lower than that for the La{sub 2}CuO{sub 4} bulk powder. The nanofibers were of higher specific surface area (105.0 m{sup 2}/g), metal copper area and copper dispersion. The in situ FTIR and EPR experiments were employed to study the catalysts and catalytic process. In the nanofiber catalyst, there were oxygen vacancies. H{sub 2}-reduction resulted in the generation of trapped electrons [e] on the vacancy sites. Over the nanofiber catalyst, the intermediate H{sub 2}CO/HCO was stable and was reformed to CO{sub 2} and H{sub 2} by steam rather than being decomposed directly to CO and H{sub 2}. Over the bulk counterpart, apart from the direct decomposition of H{sub 2}CO/HCO to CO and H{sub 2}, the intermediate H{sub 2}COO might go through two decomposition ways: H{sub 2}COO=CO+H{sub 2}O and H{sub 2}COO=CO{sub 2}+H{sub 2}. - Graphical abstract: The steam reforming of methanol (SRM) to CO{sub 2} and H{sub 2} over La{sub 2}CuO{sub 4} nanofiber catalyst was studied. At the temperature as low as 150 deg. C, methanol was completely (100%) converted to hydrogen and CO{sub 2} without the generation of CO. Within the 60 h catalyst lifespan test, methanol conversion was maintained at 98.6% and with 100% CO{sub 2} selectivity.
- OSTI ID:
- 21043853
- Journal Information:
- Journal of Solid State Chemistry, Vol. 181, Issue 1; Other Information: DOI: 10.1016/j.jssc.2007.10.029; PII: S0022-4596(07)00443-4; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CALIBRATION STANDARDS
CARBON DIOXIDE
CARBON MONOXIDE
CATALYSIS
CATALYSTS
CRYSTALS
CUPRATES
ELECTRON SPIN RESONANCE
FOURIER TRANSFORMATION
HYDROGEN
INFRARED SPECTRA
LANTHANUM COMPOUNDS
METHANOL
NANOTUBES
SPECIFIC SURFACE AREA
TEMPERATURE RANGE 0065-0273 K
TRAPPED ELECTRONS
VACANCIES
WATER