细菌纤维素-石墨烯协同增强金属酞菁催化活性的增效机制研究

The catalytic activity of heterogeneous metal phthalocyanine (MPc) catalyst is determined by both the microstructure of the support and the electron transfer efficiency of MPc during the catalytic process. In this program, a highly-reactive MPc-based catalytic reaction system was constructed following the principle of “improving the adsorption of target molecules, facilitating the electron transfer of MPc, the support deeply participating in the catalytic reaction”. Bacterial cellulose has controllable structure and is high affinity to target molecules, while graphene has outstanding electrical conductivity and very large surface-to-volume ratio, we suppose the combination of these advantages to prepare bacterial cellulose-graphene nanocomposite for MPc immobilization will greatly improve the catalytic activity of MPc. The resulting MPc immobilized bacterial cellulose-graphene heterogeneous catalyst was utilized for the decoloration of dye pollutant, with H2O2 as an oxidant. The structure-performance relationship between the heterogeneous catalyst and the degradation efficiency of pollutant, the interaction between MPc and graphene, the mechanism of synergistic enhancement of catalytic activity of MPc with bacterial cellulose and graphene, and the catalytic reaction mechanism of the heterogeneous catalyst will be studied thoroughly. This program, which focuses on elucidating the enhancement mechanism of the catalytic activity of the heterogeneous MPc, is multidisciplinary of polymer material science, environmental science and catalysis science. It is of vital importance both in academic research and in industry practice to explore eco-friendly heterogeneous MPc-based functional material and its application for environmental purification.

异相金属酞菁催化剂的催化活性受控于载体材料的微结构和金属酞菁的电子转移效率双重因素，本项目从“促进底物分子吸附、提高电子转移效率、载体深度参与催化反应”的理念出发构建催化反应体系，巧妙结合结构可调控、亲和性强的细菌纤维素和导电性良好、比表面积巨大的石墨烯两者的优势，设计构筑系列细菌纤维素-石墨烯耦合金属酞菁异相催化剂，以染料有机污染物为催化对象、H2O2为氧化剂研究其催化性能。项目重点研究异相催化剂与有机污染物降解的构-效关系、细菌纤维素与石墨烯之间的相互作用机理和细菌纤维素协同石墨烯增强金属酞菁催化活性的增效机制，深入揭示异相催化剂降解有机污染物的催化作用机理。本项目交叉融合高分子材料科学、环境科学和催化科学等多个学科，通过系统研究，阐明异相金属酞菁催化剂的催化活性增效机制，为制备新一代功能催化剂提供新思路，同时对异相催化材料在环境净化领域的应用也具有重要的学术和应用价值。

金属酞菁（MPc）的催化活性同时受控于分子状态、底物亲和性和电子传递效率三重因素。由此基础原理出发，本项目巧妙设计构筑一系列基于“基体增强效应”的超高活性“细菌纤维素-石墨烯基金属酞菁异相催化材料”（MPc@GBC）。通过原位生物合成技术制备获得细菌纤维素-石墨烯/氧化石墨烯（GBC/GOBC）纳米复合基体。基于密度泛函理论计算从分子水平上解释了细菌纤维素和石墨烯/氧化石墨烯之间的相互作用机理，通过非共价作用理论分析证实细菌纤维素和石墨烯之间存在广泛的CH-相互作用，而细菌纤维素的O(3)-H和O(6)-H位与氧化石墨烯的氧原子之间存在强烈的氢键相互作用。MPc可通过共价键合和-相互作用等形式固定于GBC上，从而制备得到系列MPc@GBC异相催化材料。将MPc@GBC应用于染料、酚类等有机污染物的催化降解处理，详细研究了整个吸附和催化反应过程。GBC基体的特异三维网络框架结构和石墨烯的高亲和性，使得有机底物分子极易被MPc@GBC吸附，其平衡吸附数据较好地符合Freundlich等温吸附模型。以H2O2为氧化剂，MPc@GBC可使染料等有机污染物快速催化氧化降解，且具有优异的循环使用性能。通过电荷密度差分析证实存在一条由石墨烯指向MPc的电荷转移途径，由此促进了催化反应过程中MPc的电子转移效率，使得高活性羟基自由基的形成速率增加，从而显著提升MPc催化剂的催化活性。基于理论计算和实验结果，提出了一个通过GBC基体提高MPc催化活性的“基体增效”创新性催化作用机理。本项目通过系统研究，制备获得系列超高活性MPc@GBC异相催化材料，阐明“基体增效”创新机理，为先进功能材料设计提供新思路，同时对异相催化剂在环境净化领域的应用也具有显著的学术和应用价值。