ZnxCeO2 nanorod as active catalyst for CO2 conversion into carbamates

Abstract

Carbon dioxide, as a non-toxic and commonly available gas, can be transformed into useful chemicals such as carbonates, carbamates, urethanes, substituted ureas, methanol, and hydrocarbons. We have found the cycloaddition of CO₂ and ethanolamine is a significant method for producing cyclic carbamates. The main aim of this study is to develop a stable and efficient catalyst that gives excellent selectivity for the direct synthesis of 2-oxazolidinone from CO₂ and ethanolamine. The CeO₂ nanorods (CeO₂ r) comprise a higher percentage of oxygen vacancies than the cubic and bulk forms of CeO₂. The synthesized Zn_0.1CeO₂ catalyst further improved the formation of oxygen vacancy sites and the surface reducibility of CeO₂ from Ce⁴⁺ to Ce³⁺ thereby facilitating the activation of CO₂ and amines. In situ FTIR has been used to examine the adsorption of ethanolamine and CO₂ on the catalyst as a function of temperature. Under the optimum reaction conditions, excellent conversion of ethanolamine (93.5%) and outstanding selectivity towards 2-oxazolidinone (98%) were achieved.