Ce⁴⁺/Co³⁺ engineered hetero-structured bifunctional macroporous catalyst for enhanced and selective carbonylation of glycerol using urea

The one-pot carbonylation of glycerol-to-glycerol carbonate (GC) using urea is gaining increasing popularity in recent times, as it facilitates the conversion of two by-products into a commercially important commodity. However, it is still challenging to design an efficient heterogeneous catalyst of high activity and selectivity to GC. In this study, a highly porous CeO₂-impregnated Co₃O₄ bi-functional catalyst has been tailored and employed as a novel catalyst, which is highly active and selective to GC (88.6 ± 5% yield; 100% selectivity) via glycerolysis of urea. Detailed catalyst characterization studies using SEM, HRTEM, XRD, XPS, and NH₃/CO₂-TPD revealed that with the increase in Ce loading in Co₃O₄, the heterojunction of Ce⁴⁺ and Co³⁺ is created which serves as a strong acidic site and along with surface hydroxyl groups, together they catalyze the activation of urea and glycerol respectively resulting in highly selective production of GC in excellent yield. This furnishes new avenues for tailor-designing heterojunction catalysts that are tuneable and scalable for the industrial production of GC.