Research paperEffect of γ-alumina nanorods on CO hydrogenation to higher alcohols over lithium-promoted CuZn-based catalysts

•The introduction of γ-Al2O3 nanorods and Al3+ ions to a Li-promoted Cu-Zn-based catalyst promotes CO hydrogenation to higher alcohols.•The enhanced catalytic performance of the catalyst is due to the reduction in CuO crystallite size and due to the increase in basicity.•A Li-Cu0.45Zn0.45Al0.1 catalyst supported on γ-Al2O3 nanorods is the most optimized for the synthesis of 2-methyl branched alcohols among the higher alcohol products.•The modified catalyst exhibits excellent thermal stability over long-term reactions due to the sintering resistance of nanorods and a refractory CuAl2O4.

To achieve high catalytic activities and long-term stability to produce higher alcohols via CO hydrogenation, the catalytic activities were tuned by controlling the loading amounts of γ-alumina nanorods and Al3+ ions added to modify Cu-Zn catalysts promoted with Li. The selectivity of higher alcohols and the CO conversion to higher alcohols over a Li-modified Cu0.45Zn0.45Al0.1 catalyst supported on 10% nanorods were 1.8 and 2.7 times higher than those with a Cu-Zn catalyst without nanorods and Al3+ ions, respectively. The introduction of the thermally and chemically stable γ-Al2O3 nanorod support and of Al3+ to the modified catalysts improves the catalytic activities by decreasing the crystalline size of CuO and increasing the total basicity. Along with the nanorods, a refractory CuAl2O4 formed by the thermal reaction of CuO and Al3+ enhances the long-term stability by increasing the resistance to sintering of the catalyst.

Graphical abstractDownload high-res image (209KB)Download full-size image