Effect of Configuration Addition of Precursors on Structure and Catalysis of Cu/SiO2 Catalysts Prepared by Ammonia Evaporation-Hydrothermal Method

The effect of a precursors configuration addition on the texture, composition, morphology, and catalytic performance of Cu/SiO2 catalysts, prepared by the ammonia evaporation-hydrothermal method (AEH), was investigated. Different configuration additions of the precursor have significant impacts on the chrysocolla (Cu2Si2O5(OH)(2)) content, which determines the metal copper specific surface area due to the differing copper particle size and reducibility. The Lewis acid and basic sites of the reduced catalyst surface are linearly dependent on the copper specific surface area. In gas-phase hydrogenation of ethyl acetate to ethanol, the Lewis basic and acid sites have a synergistic effect on ethanol selectivity. The proper configuration addition of the precursors gave rise to the highest ethanol selectivity of 96% at reaction conditions of P = 2.40 MPa, T = 553 K, H-2/AcOEt (molar ratio) = 40, liquid hourly space velocity (LHSV) = 1 h(-1), and AcOEt/H2O/EtOH (mass ratio) = 90/6/4.