Carbon nanofiber-based copper/zirconia catalyst for hydrogenation of CO₂ to methanol

This article describes the synthesis of methanol by the direct hydrogenation of CO₂ over Cu/ZrO₂ catalyst at different ZrO₂ concentrations (5, 10, 15, 20 and 25 wt.%) in a three-phase phase reactor. The techniques of N₂ adsorption/desorption, x-ray diffraction, x-ray photoelectron spectroscopy, transmission electron microscopy, temperature-programmed desorption by CO₂, N₂O chemisorption and inductively coupled plasma optical emission spectrometry were employed for catalyst characterization. At a reaction temperature of 180 °C, pressure of 3.0 MP and 0.020 g/mL of the catalyst, the conversion of CO₂ and the yield of methanol were 10% and 25 g/kg.h, respectively. Surface area of the metallic copper was increased from 8.1 to 9.5 m²/g with the presence of ZrO₂ from 5 to 15 wt.%. The methanol turnover frequency exhibited a linear relationship with ZrO₂ concentration. Methanol synthesis rate was progressively increased with increasing fraction of dispersed copper. A comparative study with the literature revealed better activity of this novel catalyst at relatively low reaction conditions.