The effect of thermal treatment on the ITDI activated carbon and calcination temperature on the thermocatalytic decomposition of methane

• Main Author: Dao, Tam Nha
• Format: text
• Language: English
• Published: Animo Repository 2011
• Subjects: Methane; Catalysts; Decomposition (Chemistry); Chemical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/6925; https://animorepository.dlsu.edu.ph/context/etd_masteral/article/12778/viewcontent/CDTG005037_P.pdf
• Institution: De La Salle University

Thermocatalytic decomposition of methane is the focus of this study because of its environmental considerations. Nickel has been known as the most efficient catalyst for methane decomposition. To increase the activity and lifetime of monometallic catalysts, the development of bimetallic catalysts has been investigated. It was reported that the addition of palladium into nickel catalyst could improve the catalytic activity and life time for methane decomposition into hydrogen and carbon fibers. This study determined the combined effect of thermal treatment and calcination temperature on ITDI-AC (Industrial Technology Development Institute-Activated carbon) for the thermocatalytic decomposition of methane. The temperature for thermal treatment of activated carbon as well as the calcination temperature of catalyst were varied. Catalyst surface area, morphology, surface elemental composition, total composition and crystal structure were determined using BET, SEM, AAS, and XRD respectively. Activity test of the catalyst for thermocatalytic decomposition of the methane was conducted to determine methane conversion and the hydrogen yield. BET results revealed that surface area of activated carbon decreased with an increase in the temperature for thermal treatment while there was no significant effect of the calcination temperature on the surface area of activated carbon. The surface area of PdNi/AC catalysts increased as calcination temperature increased. This is due to formation of larger pores with an increase in the temperature for thermal treatment. AAS results showed that the average surface nickel content and palladium content of the catalyst were 1.08 and 3.2 wt.%, respectively. SEM results revealed that the size of nickel particles was larger than that of palladium particles and there was a formation of carbon fiber at reaction temperatures of 750 and 950oC. This formation increased as reaction temperature increased. XRD results revealed that there was only Ni and Pd in the catalyst and there was a formation of Pd-Ni alloy at 950oC. The catalyst (sample code PdNi/AC700_500) which included palladium nickel over activated carbon thermally treated at 700oC and calcined at 500oC showed a higher catalytic activity at 950oC than the others with hydrogen yield of 0.4057 and methane conversion of 36.62%. PdNi/AC700_500 catalyst also showed high stability at 950oC with hydrogen yield of 0.0276 after 24h.