CO hydrogenation to higher alcohols over CuZnAl catalysts without promoters: Effect of pH value in catalyst preparation

•pH value had significant influence on the catalytic activity.•Catalyst prepared at pH = 8 showed the best catalytic performance.•Larger Cu0 particle size and a suitable amount of acid favored C2 + OH formation.

CO hydrogenation to higher alcohols (C2 + OH) was examined in a slurry bed reactor. CuZnAl samples without promoters were prepared by a complete liquid-phase method at different pH value (pH = 7-10), with the aim of studying the influence of pH value on the catalytic performance in this catalytic reaction. The pH value had significantly influence on the Cu0 crystallite size, the amount of reducible Cu+, surface Cu/Zn atomic ratios and the acidity, which led to the diverse activities toward C2 + OH synthesis. Characterization results showed that relatively larger crystallite size of Cu0 and a suitable amount of acid sites was beneficial to the formation of C2 + OH. Activity results indicated that the sample prepared at pH = 8 exhibited the best catalytic performance compared with other samples. In addition, the catalytic performance of pH = 8 sample showed that increasing temperature favored to the formation of C2 + OH.

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