Insight into the Tunable CuY Catalyst for Diethyl Carbonate by Oxycarbonylation: Preparation Methods and Precursors

Three different methods were used to prepare CuY catalysts, which play an important role in Cu loading and ion-exchange level during the oxidative carbonylation of ethanol to synthesize diethyl carbonate. Of the prepared CuY catalysts, those synthesized by the ammonia evaporation method exhibited a significantly enhanced activity compared to those obtained by the other two methods. In addition, under optimized conditions, four different copper precursors were applied to adjust the textural properties and chemical states of the CuY catalysts. To obtain a deep understanding of their structure-performance relationship, XRD, XPS, CO adsorption, DRIFTS, and NH3 TPD were conducted to characterize the CuY catalysts. The experimental results indicated that the catalytic performances were in line with the proportions of Cu+ in CuY catalysts, which can be regulated by cupric precursors. In addition, the textural structures of the catalysts and the acidity and type of Cu+ species influenced by the precursors were all responsible for the activity and product distribution.