An investigation into the impact of CuAl2O4 hydrophobization on catalyst structure and performance for syngas conversion

Abstract

The intricate structure and surface properties of metal oxide catalysts pose a challenge for implementing hydrophobic surface treatment. Herein, the surface of CuAl2O4 catalysts is modified by means of grafting and bridging different saturated fatty acid molecules, including lauric acid, palmitic acid and stearic acid. Consequently, the modification leads to an enhancement in the hydrophobicity of the catalyst, as evidenced by an increase in the static water contact angle from 15.26° to 150.74°. The hydrophobization of CuAl2O4 catalysts, in turn, influences the decomposition and reduction capacity of CuAl2O4, thus favoring the formation of a more stable defective spinel structure and improving the dispersion of Cu particles, thereby restraining aggregation. Notably, the activity results indicate that the hydrophobically modified CuAl2O4 exhibits higher CO conversion and selectivity of dimethyl ether, while effectively suppressing the water–gas shift reaction and reducing CO2 selectivity. This observation points to the significance of the catalyst surface hydrophobicity in enhancing catalytic performance.