Plasma-Pretreated Catalyst for Methanol Synthesis From Syngas

A new catalyst preparation method by combining the traditional coprecipitation method with an oxygen plasma pretreatment was developed in this paper. The ternary Cu/Zn/Al catalyst powders were first prepared by coprecipitation method, and then pretreated by the plasma in a fluidized-bed dielectric barrier discharge reactor with a carrier gas of a molar ratio of O₂/Ar = 5/95. Then, the plasma-pretreated catalyst was conducted with the methanol synthesis test at the following conditions: H₂/CO/N₂ = 64/32/4, Q = 900 seem, P = 4 MPa, and T = 255degC. The plasma pretreatment could enhance the catalytic activity, e.g., the methanol selectivity increased from 28% to 72% and the methanol yield from 0.19 to 0.52 g/g_cat. middot h, although the CO and H₂ conversions were slightly decreased. On the other hand, the BET, inductively coupled plasma/optical emission spectroscopy, and X-ray diffraction analysis found that the catalytic properties did vary after plasma pretreatment. In short, this paper reveals that the plasma pretreatment is a viable process for preparation of Cu/Zn/Al catalyst in terms of methanol synthesis.