Catalytic behavior and surface species investigation over γ-Al2O3 in dimethyl ether hydrolysis

•Experimental and DFT investigation of DME hydrolysis on the active site of γ-Al2O3.•Insight into reaction mechanism and adsorbed surface species on alumina.•Reaction behaviors and thermodynamics.•DME hydrolysis at the OH group bridging the two Al atoms on (1 1 0) surface.•The higher acidity of the OH group on (1 1 0) than on (1 0 0) hydroxylated surfaces.

The catalytic behavior and surface species over γ-Al2O3 in hydrolysis of dimethyl ether (DME) was examined by experimental and theoretical studies. It was experimentally observed that γ-Al2O3 substantially catalyzed DME hydrolysis producing methanol at 250–350 °C with high stability at this temperature range with respect to carbon formation. Other carbon-containing species yielded from side reactions were present in trace amounts at temperatures below 375 °C. The Density Functional Theory calculations results suggested that DME hydrolysis is thermodynamically favorable on the hydroxylated γ-Al2O3(1 1 0) but it is not favorable on (1 0 0) surfaces at this reaction temperature range. The DME hydrolysis on γ-Al2O3 is more likely to occur at a hydroxyl surface group which has relatively high acidity.

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