Synthesis of stable Cu-MCM-41 nanocatalysts for H2 production with high selectivity via steam reforming of methanol

Abstract

Available online xxxKeywords: Steam reforming Cu-MCM-41 Metal loading One-pot synthesis Catalyst deactivation N 2 O chemisorption a b s t r a c t High surface area MCM-41 containing copper catalysts (with different loading from 5 to 20 wt%) were synthesized using one-pot procedure for steam reforming of methanol (SRM) studies. A variety of techniques including BET, XRD, TGA-DSC, TEM, EDX, ICP-OES, H 2 -TPR, N 2 O chemisorption and EPR were used to characterize the physical and chemical properties of catalysts. Structural characterization by means of XRD and BET revealed that %Cu loading has a strong influence on the ordered structure and the textural properties of the Cu-MCM-41 catalysts. The BET surface area of MCM-41 decreased from 1039 to 662 m 2 /g with increase in Cu loading from 0 to 15 wt% and then dropped to 314 m 2 /g with the loss of ordered structure at 20 wt% loading. The chemical composition analyses of catalysts using ICP-OES and EDX showed that the intended amount of copper was successfully retained in MCM-41 during one pot synthesis. Steam reforming of methanol for hydrogen production was carried out in a fixed bed reactor at atmospheric pressure in the temperature range of 200e350 C. The effect of %Cu loading, reaction temperature, CH 3 OH/H 2 O molar ratio, reactants space velocity, catalyst time on-stream on the catalytic activity and selectivity were investigated. The Cu-MCM-41 samples showed excellent catalytic performance for the SRM reactions. The best results were obtained with 15%Cu-MCM-41 which showed 89% methanol conversion, 100% H 2 selectivity and CO selectivity of 0.8% at 300 C and 2838 h À1 GHSV. However, methanol conversion decreased to about 77% when the loading of Cu was increased to 20 wt%. This can be attributed to more than 50% decrease in catalyst surface area leading to decrease in Cu-dispersion. The catalyst with 15 wt% loading showed strong resistance to deactivation and maintained consistent performance over a time onstream for 48 h, indicating that the use of high surface area MCM-41 support significantly enhanced the stability of Cu-based catalyst.ScienceDirect j o urn al h om epa ge: www.elsev ier.com/locate/he i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 5 ) 1 e1 4 http://dx.Please cite this article in press as: Deshmane VG, et al., Synthesis of stable Cu-MCM-41 nanocatalysts for H 2 production with high selectivity via steam reforming of methanol, International Journal of Hydrogen Energy (2015), http://dx.

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