Abstract
Two series of molybdena catalysts supported on a copper treated fumed silica were prepared and their properties for the selective oxidation of methane to formaldehyde were compared with the copper free analogs. The catalysts were tested at ambient pressure in a fixed bed microreactor using a 5:1 CH4:N2O mixture in the temperature range 500-600C. In a second series of tests the propensity of silica and alumina supports to catalyse the decomposition of formaldehyde was assessed. The copper free catalysts lost their selectivity to formaldehyde when the MoO3 loading exceeded 5wt% but loadings up to 15wt% were possible with two copper treated supports without loss of selectivity. Yield of formaldehyde was superior over the copper treated catalysts also. This improved performance was associated with the ability of metallic copper to act as a co-catalyst and increasing the lability of the lattice oxygen in the supported molybdena phase. On all catalysts combustion of formaldehyde in the catalytic reactor occurred and the second series of tests showed that this combustion could occur also on the support material.
Original language | English (Ireland) |
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Pages (from-to) | 559-566 |
Number of pages | 8 |
Journal | Catalysis Today |
Volume | 6 |
Issue number | 4 |
DOIs | |
Publication status | Published - Feb 1990 |