In this work, a Pt catalyst supported on an equimolar Al 2 O 3 –CeO 2 binary oxide (Pt–Al–Ce) was prepared and applied in photo-thermo-chemical dry reforming of methane (DRM) driven by concentrated solar irradiation. It was found that the Pt–Al–Ce catalyst showed good stability in DRM reactions and significant enhancements in H 2 and CO production rates compared with Pt/CeO 2 (Pt–Ce) and Pt/Al 2 O 3 (Pt–Al) catalysts. At a reaction temperature of 700 °C under 30-sun equivalent solar irradiation, the Pt–Al–Ce catalyst exhibits a stable DRM catalytic performance at a H 2 production rate of 657 mmol g −1 h −1 and a CO production rate of 666 mmol g −1 h −1 , with the H 2 /CO ratio almost equal to unity. These production rates and the H 2 /CO ratio were significantly higher than those obtained in the dark at the same temperature. The light irradiation was found to induce photocatalytic activities on Pt–Al–Ce and reduce the reaction activation energy. In situ diffuse reflectance infrared Fourier transform spectroscopy ( in situ DRIFTS) was applied to identify the active intermediates in the photo-thermo-chemical DRM process, which were bidentate/monodentate carbonate, absorbed CO on Pt, and formate. The benefits of the binary Al 2 O 3 –CeO 2 substrate could be ascribed to Al 2 O 3 promoting methane dissociation while CeO 2 stabilized and eliminated possible coke formation, leading to high catalytic DRM activity and stability.
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This content will become publicly available on May 23, 2024
Non-equilibrium plasma-assisted dry reforming of methane over shape-controlled CeO 2 supported ruthenium catalysts
In this report, CeO 2 and SiO 2 supported 1 wt% Ru catalysts were synthesized and studied for dry reforming of methane (DRM) by introducing non-thermal plasma (NTP) in a dielectric barrier discharge (DBD) fixed bed reactor. From quadrupole mass spectrometer (QMS) data, it is found that introducing non-thermal plasma in thermo-catalytic DRM promotes higher CH 4 and CO 2 conversion and syngas (CO + H 2 ) yield than those under thermal catalysis only conditions. According to the H 2 -TPR, CO 2 -TPD, and CO-TPD profiles, reducible CeO 2 supported Ru catalysts presented better activity compared to their irreducible SiO 2 supported Ru counterparts. For instance, the molar concentrations of CO and H 2 were 16% and 9%, respectively, for plasma-assisted thermo-catalytic DRM at 350 °C, while no apparent conversion was observed at the same temperature for thermo-catalytic DRM. Highly energetic electrons, ions, and radicals under non-equilibrium and non-thermal plasma conditions are considered to contribute to the activation of strong C–H bonds in CH 4 and C–O bonds in CO 2 , which significantly improves the CH 4 /CO 2 conversion during DRM reaction at low temperatures. At 450 °C, the 1 wt% Ru/CeO 2 nanorods sample showed the highest catalytic activity with 51% CH 4 and 37% CO 2 conversion compared to 1 wt% Ru/CeO 2 nanocubes (40% CH 4 and 30% CO 2 ). These results clearly indicate that the support shape and reducibility affect the plasma-assisted DRM reaction. This enhanced DRM activity is ascribed to the surface chemistry and defect structures of the CeO 2 nanorods support that can provide active surface facets, higher amounts of mobile oxygen and oxygen vacancy, and other surface defects.
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- Award ID(s):
- 1856729
- NSF-PAR ID:
- 10434169
- Date Published:
- Journal Name:
- Journal of Materials Chemistry A
- Volume:
- 11
- Issue:
- 20
- ISSN:
- 2050-7488
- Page Range / eLocation ID:
- 10993 to 11009
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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