Study of the effect of Gd-doping ceria on the performance of Pt/GdCeO2/Al2O3 catalysts for the dry reforming of methane

• Published in: Catalysis today Vol. 355; pp. 737 - 745
• Main Authors: da Fonseca, R.O., Garrido, G.S., Rabelo-Neto, R.C., Silveira, E.B., Simões, R.C.C., Mattos, L.V., Noronha, F.B.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-09-2020
• Subjects: Biogas; Cerium-doped gadolinium; Dry reforming; Hydrogen production; Pt catalysts; Pt catalysts; Dry reforming; Biogas; Cerium-doped gadolinium; Hydrogen production
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2019.04.079

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•Pt/Al2O3 catalyst underwent severe deactivation for the dry reforming of methane.•The addition of CeGd mixed oxide to Pt/Al2O3 improved the stability of the catalyst.•The oxygen mobility of the mixed oxide inhibited the formation of carbon on Pt.•Catalyst with 36 wt% of CeGd and Ce/Gd ratio of 4 remained stable during reaction.
This work studied the performance of Pt/Al2O3 and Pt/CexGd1-xO2/Al2O3 catalysts for the dry reforming of methane at 1073 K. Pt/Al2O3 catalyst underwent severe deactivation at the beginning of reaction, whereas the deactivation of Pt/Ce0.8Gd0.2/Al2O3 and Pt/Ce0.5Gd0.5/Al2O3 catalysts was less significant. Pt/36Ce0.8Gd0.2/Al2O3 catalyst remained quite stable during reaction. in situ XRD and XANES experiments showed the formation of
oxygen vacancies and Ce3+ species during the reduction of the mixed oxide, which promoted the mechanism of carbon removal from the Pt particle. In the absence of mixed oxide, carbon deposition led to the deactivation of Pt/Al2O3 catalyst. The cyclohexane dehydrogenation reaction revealed that Pt sintering is responsible for the deactivation of Pt/Ce0.8Gd0.2/Al2O3 and Pt/Ce0.5Gd0.5/Al2O3 catalysts. The stability of Pt/36Ce0.8Gd0.2/Al2O3 catalyst is likely due to the close contact between Pt and the CeGd mixed oxide because of the higher extent of alumina coverage by the mixed oxide. This promotes the mechanism of carbon removal from the surface of Pt particles and inhibits Pt particle size growth.