双氨基功能化UiO-66的构筑及其光催化CO₂环加成性能研究

Construction of Dual-Amino Functionalized UiO-66 and Its Photocatalytic Performance for CO₂ Cycloaddition

摘要: 本文设计并合成了一种双氨基功能化的UiO-66 (UiO-66-(NH₂)₂)，系统研究了氨基数目对光催化CO₂与环氧丙烷(PO)环加成反应性能的影响。通过XRD、FT-IR、SEM/TEM和DRS表征，结果表明氨基功能化并未破坏UiO-66框架结构，同时增强了可见光吸收能力。光催化实验结果显示，UiO-66-(NH₂)₂在可见光(λ ≥ 420 nm)条件下，环氧丙烷的转化率、产率和选择性均优于UiO-66和UiO-66-NH₂，转化率可达52.89%，选择性高达98.53%。提升性能的主要原因在于：Zr⁴⁺金属中心提供Lewis酸位点，氨基作为Lewis碱位点协同活化CO₂和PO分子，并在光照下促进电子转移和反应中间体生成。该研究为设计高效MOFs基光催化剂及CO₂资源化提供了新的思路与方法。

Abstract: A dual-amino functionalized UiO-66 (UiO-66-(NH₂)₂) was designed and synthesized to systematically investigate the effect of amino group number on the photocatalytic cycloaddition of CO₂ with propylene oxide (PO). The crystal structure, functional groups, morphology, and optical properties of the samples were characterized by XRD, FT-IR, SEM/TEM, and DRS. The results indicate that amino functionalization does not destroy the UiO-66 framework, while significantly enhancing visible-light absorption. Photocatalytic experiments show that UiO-66-(NH₂)₂ exhibits superior catalytic performance compared with UiO-66 and UiO-66-NH2 under visible light (λ ≥ 420 nm) with tetrabutylammonium bromide (TBAB) as co-catalyst, achieving a PO conversion of 52.89% and selectivity of 98.53%. The improved performance is attributed to the synergistic effect between Lewis acidic Zr⁴⁺ sites and Lewis basic amino groups, which cooperatively activate CO₂ and PO molecules, while photoexcitation promotes electron transfer and the formation of reactive intermediates. This study provides a novel strategy for the design of high-efficiency MOFs-based photocatalysts and contributes to CO₂ utilization and green chemical synthesis.