Strong Cu/ZnO Interfacial Interaction Induced by ZrO₂ Promoter Suppressing the Ethanol Formation in Industrial Methanol Synthesis

The presence of ethanol as an impurity in industrial methanol significantly degrades the quality of the downstream products. Addressing the challenge of suppressing ethanol formation remains crucial in the synthesis of industrial methanol. In this context, we systematically characterized a series of commercial catalysts and evaluated their catalytic performance for methanol synthesis to elucidate the relationship between the catalyst structure and ethanol selectivity. Our performance tests indicate that the Cu–Zn–Al commercial catalyst (NG), enhanced with a ZrO2 promoter, can effectively inhibit ethanol formation, reducing it to approximately 580 ppm after 1000 h. The ZrO2 promoter stabilizes Cu0, ensuring it is highly dispersed and maintains a homogeneous structure, which is pivotal for the catalyst's exceptional performance. Analysis through temperature-programmed desorption and density functional theory (DFT) demonstrates that the high dispersity of Cu0 enhances the adsorption of CO and H2. Additionally, a uniform Cu0 active site structure contributes to the increased methanol selectivity while simultaneously suppressing ethanol formation. This study underscores the significant potential of incorporating a ZrO2 promoter in catalysts to effectively suppress ethanol production under industrial operating conditions.