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Pd/CNT-promoted CuZrO2/HZSM-5 hybrid catalysts for direct synthesis of DME from CO2/H2

Paper ID Volume ID Publish Year Pages File Format Full-Text
40547 45858 2013 8 PDF Available
Title
Pd/CNT-promoted CuZrO2/HZSM-5 hybrid catalysts for direct synthesis of DME from CO2/H2
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.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (150 K)Download as PowerPoint slideHighlights► Pd/CNTs doped CuZr/HZSM-5 shows high catalytic activity for direct DME-synthesis. ► Direct DME-synthesis from CO2/H2 markedly raises driving force of CO2 hydrogenation. ► “Stepwise precipitation–slurry mixing” is a good method to prepare hybrid catalyst.

Keywords
Pd-decorated CNTs; Pd-decorated CNT-promoted Cu-ZrO2/HZSM-5 hybrid catalysts; CO2 hydrogenation; Direct DME synthesis
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Pd/CNT-promoted CuZrO2/HZSM-5 hybrid catalysts for direct synthesis of DME from CO2/H2
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 451, 31 January 2013, Pages 28–35
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us