沸石分子筛路易斯酸位点的构建、失活及稳定化研究进展OA

Precise construction of Lewis acid sites(LAS)in zeolite molecular sieves is one of the important strategies to improve their catalytic activity.However,problems such as water induction,poisoning,carbon deposition and skeleton collapse in actual reactions can lead to the destruction and deactivation of LAS.The construction methods,deactivation mechanisms and stabilization strategies of LAS were systematically reviewed.LAS can be efficiently constructed by framework de-alumination(hydrothermal and acid treatment),metal ion doping and defect engineering,and their catalytic activity originates from the electron-deficient property of the coordinating unsaturated metal center.However,LAS are prone to coordination saturation with water molecules,high-temperature hydroxyl condensation,carbon deposition,and cation dissolution during the reaction process,leading to acid strength decay and structural collapse,resulting in deactivation.Current LAS stabilization strategies focus on:(1)Hydrophobic modification(increasing silica-aluminium ratio(molar ratio),surface functionalization)to inhibit hydrolysis;(2)Structural reinforcement(metal ion doping,preparation of physical protective layer and construction of high-entropy alloys)to delay the migration of aluminium species;(3)Hierarchical pore construction to enhance the anti carbon deposition performance;(4)LAS regeneration.Above strategies play an important role in stabilizing LAS.In the future,with the continuous development of characterization technologies and catalyst preparation technologies,researchers can accurately analyze the mechanisms of LAS deactivation and construct atomic level anti-deactivation sites.