Abstract: "In-situ" infrared spectraphotometer cell designed and constructed by ourselves has been used to identify the surface species of CO and H_2 on copper-based cata lyst at elevated pressures and temperatures. Having conquered the difficulty due to the low transparency of Cu-ZnO-Al_2O_3 catalyst, the authors have obtained convin cible experimental results concerning surface intermediates on catalyst which can be used to speculate the reaction mechanism of methanol synthesis from syngas over Cu-ZnO-Al_2O_3 catalyst.
From the spectra of CO and H_2 on catalysts, it could be drawn that M—O—C—M and M—CO and M—H are surface species under reaction conditions. A competitive adsorption between CO and H_2 on the same sites has been verified, the adsorptive capacity of H_2 at equilibrium is greater than that of CO, indicating the ther-modynamic superiority of H_2 over CO. At higher temperatures, the dissociated adsorption of H_2 dominates the active centers. At low temperatures the active centers are entirely occupied by CO.
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