超临界CO2中介孔超强酸负载金属双效催化剂的制备及其在纤维素氢解中的性能研究

Directly converting cellulose into high-valued platform chemicals and fine chemicals is one of the most attractive topics in the fields of green and sustainable chemistry. However, high selectivity to useful chemicals is difficult to be achieved due to the complex catalytic processes. In the past few years, the applications of supercritical carbon dioxide (scCO2) in synthesizing nanomaterials and in catalysis reactions have attracted much attention. In this proposal, we plan to explore the fabrication of acidic mesoporous frameworks-metal bifunctional catalysts, and their applications on catalytic converting cellulose into isosobide. This study will focus on the synthesis methodology of metal catalysts within mesoporous supports; the phase behaviors and diffusion specialty of scCO2; and the nucleation, facets modulation, and evolution mechanisms of the catalysts in scCO2.We will also study the synergistic catalysis of the bifunctional catalysts, and discover the correlation between catalysts' structure and their catalytic performances. Besides, CO2-H2O system will be used and evaluated as a new reaction system for the hydrogenolysis of cellulose. It is expected that an effective route for converting cellulose into isosobide under mild conditions can be established.

将纤维素催化转化为能源化学品、精细化学品是当前资源科学及绿色化学领域研究的热点问题之一。纤维素催化转化过程的复杂性使其高选择性地转化为单一化学品仍存在较大的难度。近年，超临界CO2绿色溶剂体系在材料制备和催化反应等领域取得了重要的进展并受到广泛关注。本课题研究超临界CO2体系中介孔固体酸/金属双效催化剂的制备和纤维素选择性催化加氢制异山梨糖醇中的基础科学问题。对超临界CO2中，介孔孔道内金属催化剂的成核、生长及微结构调控展开研究,探索超临界体系中的相行为、传质特异性、催化剂的成核及生长机理。对纤维素水解的酸催化剂以及加氢催化剂进行研究，探索酸中心与加氢活性位的相互作用，揭示双效催化剂的协同作用及构效关系。同时，探讨新的反应体系- - CO2-H2O体系在纤维素转化反应中的有效性，特异性，规律性和反应机理。在相对温和的条件系下，实现纤维素高选择性地加氢转化生成异山梨糖醇。

针对当前生物质选择性加氢脱氧反应中亟待解决的一些共性问题，项目围绕纤维素等生物质催化转化中的固体酸-金属双功能催化剂的设计制备以及催化反应中的构效关系展开研究。1）探索高性能固体酸-金属双功能催化剂制备新方法，揭示双功能催化剂中介孔结构与有效酸性位间的构效关系，以及酸中心与加氢活性中心的协同催化效应。2）研究双功能催化剂中的稳定性影响因素，揭示抑制催化剂团聚、流失、积碳的核心要素。3）研究生物质氢解催化剂中表面缺陷的控制机制及其与催化剂活性中心、催化剂稳定性的关联。本项目的实施，为高效生物质氢解催化剂的制备提供新思路和策略；为解决当前生物质氢解反应中催化剂有效活性中心不足，苛刻反应条件下稳定性不理想等问题提供参考和科学基础。