Pd-Decorated CNT-Promoted Pd-Ga2O3 Catalyst for Hydrogenation of CO2 to Methanol

• Published in: Catalysis letters 2011-06, Vol.141 (6), p.886-894
• Main Authors: Kong, Hua, Li, Hai-Yan, Lin, Guo-Dong, Zhang, Hong-Bin
• Format: Article
• Language: English
• Subjects: Carbon dioxide; Catalysis; Catalysts; Chemistry; Chemistry and Materials Science; Decoration; Exact sciences and technology; Gallium oxides; General and physical chemistry; Hydrogenation; Industrial Chemistry/Chemical Engineering; Methanol; Organometallic Chemistry; Physical Chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-011-0584-4

A type of Pd-decorated CNT-promoted Pd-Ga catalysts was developed. The catalyst displayed excellent performance for CO 2 hydrogenation to methanol. Under the reaction conditions of 5.0 MPa and 523 K, the observed specific reaction rate of CO 2 hydrogenation reached 2.23 μmol s −1 (m 2 -Pd) −1 , which was 1.39 times that (1.60 μmol s −1 (m 2 -Pd) −1 ) of the non-promoted Pd-Ga host. The addition of a small amount of the Pd-decorated CNTs to the Pd-Ga host catalyst did not cause a marked change in the E a of the CO 2 hydrogenation reaction. The function of the CNT-promoter was mainly in increasing the molar percentage of the catalytically active Pd 0 -species in the total Pd-amount at the surface of the functioning catalyst, and in improving the capability of the catalyst to adsorb and activate H 2 (one of the reactants). Compared to the “Herringbone-type” CNTs, the “Parallel-type” CNTs possess less active surface (with less dangling bonds), and thus, lower capacity for adsorbing H 2 , resulting in the rather limited promoter effect. Graphical Abstract