La2CuO4 perovskite enhanced ethylene carbonate synthesis via tuning the acid-base cooperation

A2BO4 perovskite oxides display excellent heterogeneous catalytic performance, yet the development of high-efficient A2BO4 acid-base catalysts still faces great challenges. Herein, we synthesize a series of lanthanum-copper composite oxides (La-Cu-O) with different ratios of La and Cu to investigate the effect of acid-base cooperation on ethylene carbonate (EC) synthesis. The optimal La-Cu-O-1 displays the excellent performance of urea alcoholysis to EC with ethylene glycol (EG) conversion of ∼ 100% and EC selectivity of 96.6% at 140 °C after 7 h, which is much higher than that of lanthanum oxide and copper oxide. Furthermore, La-Cu-O-1 possess higher catalytic stability than commercial catalysts (zinc oxide). Detailed studies indicate that La-Cu-O-1 with the proper acid-base cooperation can improve the hydroxyl (O−H) dissociative adsorption of EG to alkoxide and weaken the dehydration performance of intermediate (hydroxyethyl carbamate) to by-product (2-oxazolidinone), causing the high selectivity of EC. This work not only presents efficient catalysts for the urea alcoholysis, but also upgrades the study on structure-performance relationship in acid-base catalysis.