Methanol synthesis through $CO_2$ hydrogenation was studied over copper-based catalysts. The reaction was carried out in a continuous micro flow reactor with a fixed bed under 22 atm at various temperatures. And reaction mechanism was investigated by FT-IR spectroscopy.
Some binary catalysts were prepared by coprecipitation method. Through a comparative study on their catalytic behaviors, $CuO/ZrO_2$ system was selected as the most promising catalyst system.
To establish the catalyst preparation method, $CuO/ZrO_2$ catalysts synthesized by various methods were compared on their characteristics and catalytic behaviors. Among them the best catalytic activity was obtained over the catalyst prepared by the method in which both the precursors' solution and NaOH solution (precipitator) were dropped coincidently into the deionized water with pH maintained at 7.
Addition effects of some metal components(Ce, Cr, Cs, Zn, K, Pd and V) as promoters were surveyed for $CuO/ZrO_2$ catalyst. And it was found that Zn was the best promoter of all.
FT-IR spectroscopy investigation over $CuO/ZrO_2$ catalyst showed that carbonate, formate, formaldehyde and methoxy species are involved in the methanol synthesis reaction as intermediates.
