Steam reforming of dimethyl ether over H-mordenite-Cu/CeO2 catalysts

Abstract

Steam reforming of dimethyl ether (DME) was carried out over combined solid acid-CuO based catalysts. The reaction proceeded via a successive two-step mechanism: hydration of DME to methanol over solid acids, followed by steam reforming of methanol to produce H₂ and CO₂ over CuO based catalysts. Effective hydration catalysts were various zeolites including H-mordenite, SO₄²⁻/ZrO₂, and WO₃/ZrO₂ whose acid strength was Ho ≦ −3.0 or lower. When H-mordenite was combined with CuO/CeO₂ and Pd/CeO₂, a high yield of H₂ was attained. However, Pd/CeO₂ produced much CO. Combination of H-mordenite and 80 wt.% CuO/CeO₂ produced H₂ at a rate of 71 mol kg (cat h)⁻¹. Metallic copper (Cu⁰) was deduced to be the active species. The catalyst gradually lost its activity during the reaction. The cause of deactivation was not the deactivation of H-mordenite but the coke formation on copper species.