title: Improved Efficiency for Partial Oxidation of Methane by Controlled Copper Deposition on Surface-Modified ZSM-5.
abstract: The mono(μ-oxo) dicopper cores present in the pores of Cu-ZSM-5 are active for the partial oxidation of methane to methanol. However, copper on the external surface reduces the ratio of active, selective sites to unselective sites. More efficient catalysts are obtained by controlling the copper deposition during synthesis. Herein, the external exchange sites of ZSM-5 samples were passivated by bis(trimethylsilyl) trifluoroacetamide (BSTFA) followed by calcination, promoting selective deposition of intraporous copper during aqueous copper ion exchange. At an optimum level of 1-2 wt % SiO2, IR studies showed a 64 % relative reduction in external copper species and temperature-programmed oxidation analysis showed an associated increase in the formation of methanol compared with unmodified Cu-ZSM-5 samples. It is, therefore, reported that the modified zeolites contained a significantly higher proportion of active, selective copper species than their unmodified counterparts with activity for partial methane oxidation to methanol.
authors.affiliation: School of Chemistry and Chemical Engineering Queen's University Stranmillis Road Belfast BT9 5AG Northern Ireland; Institute of Catalysis Research and Technology (IKFT) Karlsruhe Institute of Technology (KIT) Kaiserstrasse 1276131 Karlsruhe Germany.
authors.forename: Thomas
authors.identifier: 0000-0002-8891-985X
authors.initials: T
authors.lastname: Sheppard
authors.affiliation: School of Chemistry and Chemical Engineering Queen's University Stranmillis Road Belfast BT9 5AG Northern Ireland.
authors.forename: Helen
authors.initials: H
authors.lastname: Daly
authors.affiliation: School of Chemistry and Chemical Engineering Queen's University Stranmillis Road Belfast BT9 5AG Northern Ireland.
authors.forename: Alex
authors.initials: A
authors.lastname: Goguet
authors.affiliation: School of Chemistry and Chemical Engineering Queen's University Stranmillis Road Belfast BT9 5AG Northern Ireland.
authors.forename: Jillian M
authors.initials: JM
authors.lastname: Thompson
keywords: Cu-ZSM-5; methane; methanol; partial oxidation; silylation