疏水型金-钯纳米粒子/金属-有机框架催化剂及其液相催化甲烷选择性氧化性能研究

甲烷作为重要的气态化石能源，广泛存在于天然气和沼气中。利用非均相催化剂将甲烷转化为液体燃料是天然气和沼气直接转化的有效策略之一。针对目前催化剂催化速率较慢、效率不高及催化剂难回收的问题，本项目拟通过在MIL-101/100系列材料负载Au-Pd纳米粒子，然后用聚二甲基硅氧烷（PDMS）疏水化修饰MOF的外表面来构筑Au-Pd@MOF-PDMS催化剂。研究Au-Pd@MOF-PDMS复合催化剂组成、微观结构、Au-Pd纳米粒子尺寸、负载量及PDMS疏水性对催化甲烷选择性氧化性能的影响。分析催化过程中的中间产物，确定催化过程中的活性物种，探讨Au-Pd@MOF-PDMS液相催化甲烷选择氧化的机理。通过总结反应规律和构效关系,建立适合于低温液相催化甲烷选择性氧化的Au-Pd@MOF-PDMS催化模型。本项目将对高效催化甲烷选择性氧化的复合型催化剂的构筑提供有价值的理论和实验基础。

Methane is one kind of important gaseous fossil fuel that widely exist in the natural gas and biogas. Conversion of methane to liquid fuel by heterogeneous catalysts is one of the effective strategies for the direct development of natural gas and biogas. However, traditional homogeneous catalysts still suffer from low reaction rate, low efficiency and difficult recycling. To solve these issues, we propose to construct a new classes of Au-Pd@MOF-PDMS catalysts for enhanced methanol productivity in methane oxidation. The catalyst is synthesized by growing Au-Pd nanoparticles within the MIL-101/100 series, followed by modification of the external surface of the MOF with PDMS. The effects of Au-Pd@MOF-PDMS composite catalyst composition, microstructure, Au-Pd nanoparticle size, loading capacity and PDMS hydrophobicity on catalytic performance is studied. After analyze the intermediate products in the catalytic process and determine the active species in the catalytic process, the mechanism of Au-Pd@MOF-PDMS liquid-phase catalytic oxidation of methane is discussed. By summarizing the reaction law and structure-activity relationship, the reaction model of the Au-Pd@MOF-PDMS catalyst which is suitable for low temperature liquid phase catalytic selective oxidation of methane will be built. In addition, our project will provide valuable experimental basis for constructing of Au-Pd@MOF-PDMS catalyst that obtain efficiently catalytic selective oxidation of methane, and is also of great importance for the development of composite catalysts.