US EPA

4699166 

Journal Article 

Hydrogen-assisted dechlorination of 1,2-dichloroethane on active carbon supported palladium-copper catalysts 

Srebowata, A; Lisowski, W; Sobczak, JW; Karpinski, Z 

2011 

Yes 

Catalysis Today
ISSN: 0920-5861 

Elsevier 

175 

1 

576-584 

10.1016/j.cattod.2011.03.038 

WOS:000295735400081 

https://search.proquest.com/docview/1672069766?accountid=171501
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A series of active carbon supported palladium-copper catalysts with varying amounts of both metal components and overall metal loading 2 wt.%, prepared by incipient wetness impregnation were characterized by temperature programmed reduction (TPR), hydrogen chemisorption, temperature programmed (palladium) hydride decomposition (TPHD), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). TPHD and XRD studies indicated that the bimetallic Pd-Cu/C catalysts exhibited a considerable degree of alloying. Pd/C, Cu/C and Pd-Cu/C catalysts were investigated in the hydrodechlorination (HdCl) of 1,2-dichloroethane in the gas phase at a relatively low reaction temperature (210-230 degrees C). All catalysts showed fair stability with time on stream (up to similar to 15 h). The Pd/C and Pd-rich Pd-Cu catalysts essentially retained their initial activity while the bimetallic samples with higher Cu content exhibited some deactivation at the initial stage of reaction. Cu-rich bimetallic samples exhibited the highest selectivities toward ethene (desired reaction product), >90%. For all bimetallic Pd-Cu/C samples, this selectivity gradually increased with time on stream. XPS studies of freshly reduced and post-reaction catalysts did not support the hypothesis that during hydrodechlorination the surface of Pd-Cu is being gradually enriched in copper, as could be expected of a higher affinity of copper to chlorine. Post-reaction deposits investigated by the temperature programmed hydrogenation (TPH) showed substantial amounts of chlorine on the copper catalyst, whereas all palladium-containing Pd-Cu/C samples exhibited only carbon-containing deposit, with C-2-hydrocarbons desorbing at a relatively low temperature (300 degrees C). Suggested interpretation of catalytic data includes both the role of C2Hx species building up on catalyst's surface during hydrodechlorination as well as the role of Pd-Cu mixed sites in the mechanism of hydrogen-assisted dechlorination of 1,2-dichloroethane. (C) 2011 Elsevier B.V. All rights reserved. 

1,2-Dichloroethane; Hydrodechlorination; Selectivity for ethene; Pd-Cu/Sibunit carbon; XRD; XPS