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Pd/CNT-promoted Cu−ZrO2/HZSM-5 hybrid catalysts for direct synthesis of DME from CO2/H2.
- Source :
-
Applied Catalysis A: General . Jan2013, Vol. 451, p28-35. 8p. - Publication Year :
- 2013
-
Abstract
- A type of bi-functional hybrid catalyst of Pd-decorated CNT-promoted Cu-ZrO2 admixed with HZSM-5 zeolite was developed, and displayed excellent performance for the direct synthesis of dimethyl ether (DME) from CO2/H2 via CH3OH in a single fixed-bed continuous flow reactor. Over a CuZr–PdCNTs/HZSM-5 hybrid catalyst under reaction conditions of 5.0 MPa, 523 K, V(H2)/V(CO2)/V(N2) = 69/23/8, GHSV = 25,000 mLSTP/(h g-hydr. catal.), the observed specific rate of CO2 hydrogenation-conversion reached 0.39 μmol/(s m2-Cu0-SA), which was 1.22 times that of the corresponding Pd/CNTs-free counterpart CuZr/HZSM-5. The addition of a minor amount of the Pd-decorated CNTs into the CuZr/HZSM-5 host catalyst caused little change in the apparent activation energy for CO2 hydrogenation, but led to an increase of metal Cu exposed area (catalytically active Cu surface-sites closely associated with the CO2 hydrogenation to methanol) and marked improvement of adsorption performance of the catalyst for H2 and CO2. The latter would help generate a micro-environment with higher concentration of active H and CO2 adspecies at the surface of the functioning catalyst, thus increasing the rate of the surface hydrogenation reactions. The present study also demonstrated that combining the methanol-synthesis and methanol-dehydration-to-DME processes in heterogeneous “one-pot” reactions by using the bi-functional hybrid catalyst could indeed enhance the driving force for CO2 hydrogenation conversion. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 0926860X
- Volume :
- 451
- Database :
- Academic Search Index
- Journal :
- Applied Catalysis A: General
- Publication Type :
- Academic Journal
- Accession number :
- 85279943
- Full Text :
- https://doi.org/10.1016/j.apcata.2012.10.038