Effect of chromium promoter on copper catalysts in ethanol dehydrogenation

A series of chromium‐promoted copper catalysts with various Cr to Cu molar ratios were prepared with the co‐precipitation method. The promotional effects of chromium on copper catalysts were examined by X‐ray powder diffraction (XRD), nitrous oxide decomposition, and the dehydrogenation reaction of ethanol. The dehydrogenation reaction was carried out in a continuous‐flow microreactor between 523 and 583 K under atmospheric pressure. The results indicated that the promotional effect was dependent on the Cr/Cu molar ratio, and the predominant decay of catalysts in this study was caused by sintering. The catalyst with the Cr/Cu molar ratio of 4/40 has the highest activity and stability. The surrounded well‐dispersed chromia strongly influenced the catalytic properties of copper metal. It also showed that the over‐promotation of a catalyst has a disastrous effect on the total make of product. The ethanol dehydrogenation reaction follows a first‐order reaction, and the kinetics for deactivation can be described by a second‐order expression.