Effect of Water Layer in a Microreactor on the Low-Temperature Synthesis of High-Activity Cu/ZnO Catalysts

The effect of a water layer on the precipitation process in a three-channel microreactor at low temperatures was investigated. Fourier-transform infrared spectroscopy, X-ray powder diffraction, thermal gravimetric analysis, X-ray photoelectron spectroscopy, temperature-programmed reduction, and Brunauer–Emmett–Teller analysis were employed for studying the structural evolution of the intermediate products during the preparation of both zincian georgeite-derived and zincian malachite-derived catalysts, and catalytic activities were measured for methanol synthesis from syngas. It is manifested that the effect of uniform precipitates acts consecutively on the subsequent aging process, Zn incorporation in precursors, thermal decomposition, reduction, and catalytic performance of the catalysts. Numerical simulation revealed the change of species properties, and reaction rates at varying temperatures can lead to different regulations of the water layer, denoting that disparate ratios of the water layer were required for obtaining uniform precipitates under different conditions, which further suggests the key role of uniformity of the precipitates in preparing high-activity Cu/ZnO catalysts.