Effect of Aging Methods on CuZnAl Catalysts for Methyl Acetate Hydrogenation

Abstract

A series of CuZnAl catalysts derived from layered double hydroxide precursors with different Cu/Zn molar ratios were synthesised by a co-precipitation method for methyl acetate hydrogenation. The best catalytic performance was obtained when the Cu/Zn molar ratio reached 0.25:1. After fixing the Cu/Zn molar ratio at 0.25:1, the effect of aging methods, including ultrasound, high shear mixer stirring, and magnetic stirring, were investigated, which showed that 0.25CuZnAl-u and 0.25CuZnAl-h exhibited a higher conversion and selectivity than that of 0.25CuZnAl-m, especially under low reaction temperatures. The physicochemical properties of the CuZnAl catalysts were characterised by X-ray diffraction, inductively coupled plasma–atomic emission spectroscopy, N2 physisorption, N2O chemisorption, transmission electron microscopy, H2-temperature-programmed reduction, X-ray photoelectron spectroscopy, and H2-temperature-programmed desorption. It was found that compared with 0.25CuZnAl-m, 0.25CuZnAl-u and 0.25CuZnAl-h possessed a stronger interaction between Cu and the support, smaller copper particle size, and higher copper dispersion, which improved the catalytic performance.