Graphene exhibits outstanding mechanical,electrical,thermal,and optical properties,showcasing immense potential in enhancing the performance of polyimide composites.The unique two?dimensional characteristics of graphene allow for easy structural design and functional modification,presenting new opportunities for synthesizing polyimide composites with special functionalities.This review article provides a comprehensive overview of the research progress in graphene/polyimide nanocomposites in areas such as conductivity,mechanical properties,thermal properties and electromagnetic shielding.A systematic analysis was conducted on the influence of graphene's structure and functional modification on the performance of graphene/polyimide nanocomposites.Additionally,the application domains of different types of graphene/polyimide composites were discussed,with a detailed exploration of the interface interactions between graphene and the polyimide matrix and their impact on the properties of the nanocomposites.This article serves as a reference and inspiration for the subsequent development of multifunctional and high?performance graphene/polyimide nanocomposites.

Different morphology CeO₂ was used as a catalyst to catalyse the synthesis of trimethylene carbonate from CO₂ and 1,3?propanediol.The structure and composition of cerium oxides were characterized by SEM, TEM, XPS and XRD. The results showed that the yield of trimethylene carbonate was up to 72.5% at 130 ℃ for 4 h when using the rod?shaped cerium oxide as catalyst and 2?cyanopyridine as dehydrating agent. R?CeO₂ has a higher number of defect sites and an suitable specific surface area, The average particle size is small and it has moderate number of Lewis acidic sites. Based on this, the substrate range was expanded, and the experimental results showed that both five?membered cyclic carbonates and six?membered cyclic carbonates could be obtained in good yields.

A new method for the synthesis of esters by C=C bond breaking in olefins has been realised using cobalt nanoparticles (Co?NC?900) as catalysts and oxygen as oxidant.The catalytic system has a wide range of substrate applications and functional group compatibility.A diverse set of mono? and multi?substituted aromatic and aliphatic alkenes could be effectively cleaved and converted into the corresponding esters by C=C bond cleavage. In addition, the catalyst can be recycled up to six times without significant loss of activity.Characterization analysis revealed nanostructured nitrogen?doped graphene?layer coated cobalt nanoparticleis possibly responsible for excellent catalytic activity.Mechanistic studies revealed that alcohols or ketones derived from olefins under oxidative conditions are formed as intermediates,which subsequently are converted to esters through a tandem sequential process.