生物质炭纳米片层结构重组、仿酶活性簇组装与催化生物质转化

The research for the fine transformation of various components in biomass to highly-added value of fine and energy chemicals is of very important scientific and practical meanings to realize the highly efficient utilization of renewable resources and solve the increasing depletion of fossil resources and other issues. For the recent development of biomass-based non-porous carbon materials exist in terms of unstable skeletal structure, lower sulfonic acid density, single active function, lower mass transfer and transformation efficiencies in the catalytic conversion of biomass in water, for the first time this project proposes to develop the preparation method and technique for the novel biomass carbon carriers with a high sulfonic acidity, chemical intercalation, peel and reconstruction between dense stacking nanosheet layers and the assembly methodology for the construction of a series of biomimetic active clusters, which obtain the novel hierarchical layered-/meso-porous HMBCMEC biomimetic catalysts with the excellent catalytic performance for the fine transformation of various components in biomass. The controllable preparation technology of HMBCMEC catalysts will be developed by systematically checking the effect of the preparation methods and conditions of HMBCMEC catalysts on their structures and properties, At the same time, the relationship between the intrinsic properties of biomimetic catalyst’s components, structures and active clusters and their catalytic performances, as well as the mechanism of heterogeneous catalysis process are obtained by systematically researching the effect of various biomimetic catalysts and process parameters on the catalytic conversion efficiency of various components in biomass, which provides the theoretical principle to develop the preparation technology of novel HMBCMEC biomimetic catalysts and the green catalysis process for the synthesis of biomass fine chemicals.

开展生物质各组分高效转化为高附加值精细化学品的研究，对实现可再生资源的高效利用及化解化石资源日益枯竭等问题具有重要的科学和现实意义。本项目针对近来发展的非孔型生物基炭材料在催化生物质临水转化中存在骨架结构不稳定、磺酸量低、活性位单一、传质与催化效率低等问题，创新性地提出发展具有高磺化活性的生物炭基材料的制备，其致密堆集炭纳米片层间的化学插层、剥离与结构重构，及其用于系列仿酶活性蔟的组装技术，获得对生物质各组分具有优良催化转化性能的多级层间/介孔HMBCMEC仿酶催化剂。通过系统考察HMBCMEC的制备工艺条件与其结构、性能之间的关联规律，获得其可控制备技术。通过研究系列仿酶催化剂对生物质各组分的催化转化效率与转化过程因子之间的关联规律，获得其组成、结构、活性蔟本征特性与催化性能间的构效关系及其多相催化作用过程机制，为发展新型仿酶催化剂制备及生物基化学品的绿色催化合成方法与技术提供理论指导。

围绕生物基平台化学品精准合成过程中须要解决的生物炭基催化剂骨架稳定性、孔结构和活性位适用性的问题，本工作采用先进的炭化和结构重组策略，成功设计合成了一系列具有仿纤维素酶/金属酶的生物质衍生的炭基催化材料，它们在纤维素等碳水化合物水解、水解加氢等转化为还原糖、葡萄糖、山梨醇、5-羟甲基糠醛等生物基平台化合物中显示优异的催化活性和选择性、以及优良的重复使用性。用各种表征技术开展了催化剂的孔结构、形貌和表面酸性、以及仿酶活性簇与其催化性能之间的构效关系研究。值得指出的是：含磷、磷-硅多孔生物质炭催化材料具有优异的骨架稳定性和丰富的分级孔结构、以及超强的-1,4-糖苷键亲和性，作为理想的仿纤维素酶模型催化剂，在催化碳水化合物水解转化反应中催化性能优异，纤维素水解的葡萄糖收率达80%；其载钌的双功能催化剂在相对温和的反应条件下，能高效实现碳水化合物水解加氢转化为六碳醇（收率达90%），其催化效率（TOF，50-165）远远超过目前文献报道的水平。其次，生物质衍生的功能化碳量子点络合铬、锆、铝组装的系列仿金属酶催化剂在催化糠醛、乙酰丙酸/酯（LA/LAE）的氢转移合成糠醇（FA）、-戊内酯，以及FA醇解合成LAE反应中显示出优异的催化活性和稳定性，其目标产物的收率高于98%。而且通过优先酯化策略，实现高浓度LA的几乎定量转化为-戊内酯，其TOF比文献报道最好的高出近3倍，没有任何失活。更重要的是：首次采用水热催化炭化法制备超高磺酸密度（5mmol.g-1）的固体酸；采用硅胶隔离/负载策略，首次制备了两类具有骨架稳定与分级孔结构的炭基固体超强酸，并实现了其酸强度和热稳定性的可逆调控策略，制备出了一类具超高热稳定性的固体超强酸。由于其优异传质性能，这些固体超强酸在各类酸催化反应中，其催化效率和稳定性与商业化大孔磺酸树脂相比具有压倒性的优势，有望广泛用于酸催化各类转化反应过程。