Abstract
Ru-based eggshell-type catalysts, in which Ru is located at the outer region of the pellet, were prepared by the impregnation method, using spherically shaped γ-Al2O3 pellets for steam-methane reforming (SMR). Ru was only supported on the external region of the pellet because of the strong interaction between its precursor and the alumina pellet. The Ru precursor penetrated the inside of the pellet by adding nitric acid to the impregnation solution. The distribution and thickness of the Ru layer in the catalyst can be controlled using the HNO3/Ru molar ratio and contact time at the impregnation step. Among the catalysts, the graded eggshell-type catalyst showed the highest activity and long-term stability in the SMR reaction. In addition, in the daily startup and shutdown (DSS) operation, similar to the hydrogen production environment for domestic polymer electrolyte membrane fuel cells (PEMFC), the graded eggshell-type catalyst showed high activity and stability after multiple cycles. Based on the experimental studies, it was confirmed that Ru-based catalysts are suitable for steam-methane reforming for PEMFC.
Highlights
Hydrogen is a prospective energy carrier and it has attracted attention because it can be stored and transported, efficiently, and burns to produce only water as a byproduct
Prepared catalysts are designated as RA (a, b h), where “RA” indicates “Ru/Al2O3” catalysts, “a” designates the HNO3/Ru molar ratio, and “b” indicates the contact time (e.g., RA (10, 1 h) is a catalyst with an HNO3/Ru molar ratio of 10 and a contact time of 1 h.)
All pellets had a black color due to Ru oxide, and the surface increased in brightness with the HNO3/Ru molar ratio when the contact time was 1 h
Summary
Hydrogen is a prospective energy carrier and it has attracted attention because it can be stored and transported, efficiently, and burns to produce only water as a byproduct. Among the various ways of using hydrogen, polymer electrolyte membrane fuel cells (PEMFCs) are employed in residential fuel cells due to their large energy density, high calorific value, and abundant resources [1]. The H2 gas will be generated onsite by reforming available fuels, such as natural gas (mostly methane), before the fuel gas enters the fuel cell stack. Several processes for producing hydrogen using methane reforming are available: steam reforming, dry reforming, partial oxidation, etc. Steam-methane reforming (SMR) is the most commonly used process, described by Equation (1). The reformer operates at high temperatures (1073 K–1373 K) because SMR is an endothermic reaction, and the steam is fed more than CH4 to avoid coke formation, based on methane decomposition (2) and the Boudouard reaction (3)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
