新型纳米碳/碳化物复合材料的合成及其纳米碳结构在催化脱氢中的功能

The high cost and low stability of noble metal catalysts for dehydrogenation of liquid organic hydrides limit their application. The supported metal carbides as an efficient substitute for noble metal catalysts are ofen prepared by the multiple process. Based on the exist problems, nanocarbon particles with controllable structures and morphologies will be self-assembled and metal oxides are carbonized in-situ by the microwave-assisted one-step method, which is simple and efficient. The formation mechanism of nanocomposites will be explained clearly by the easy adjusting of conditions and parameters of synthesis, and the characterizations of transmission electron microscope and X-ray photoelectron spectroscopy techniques. And then the regulation of micro-/nanostructures and morphologies of nanocarbon, and surface properties of metal carbides will be achieved. Catalytic properties and kinetics of nanocomposites are studied systematically using dehydrogenation of liquid organic hydrides as research systems, and then the structure fuctions of nanocarbon are explored and clarified. Based on the study results, the interrelationship of properties and carbon structures, mophologies and surface properties will be established. After the systematical studies, the catalytic properties of metal carbides similar to noble metals will be utilized effectively, and the problems of high cost and low stability of catalysts will be solved based on the easy ragulations of the structures and morphologies of nanocarbon. The theoretical and technical evidences will be provided to design and develop novel nanocomposite materials of metal carbides with optimal structures and functions which can substitute for precious metals, and then the foundations will also be established to achieve hydrogen storage technology of liquid organic hydride.

针对目前制备碳负载碳化物过程繁琐、有机氢化物脱氢催化剂成本高和稳定性低的问题，拟通过微波辅助的方法一步自组装结构和形貌可控的纳米碳，同时实现氧化物还原碳化，完成纳米碳与碳化物的原位复合，该方法简单、高效。利用合成条件和技术参数的易调变性，结合电镜和X光电子能谱等多种表征分析手段，阐明纳米复合物的形成机理，实现对纳米碳微纳结构、形貌和纳米碳化物表面性质等的调控；利用液态有机氢化物的脱氢反应作为探针，通过对纳米复合材料的催化性能和催化动力学研究，阐明纳米碳微结构在催化反应中的功能，建立纳米碳结构、形貌和碳化物表面性质等与其催化性能之间的构效关系，通过利用纳米碳结构和形貌的可调变性，有效利用碳化物的催化性能，从而解决脱氢催化剂成本高和稳定性低等问题，为设计和开发结构与功能一体化的新型可替代贵金属催化剂提供理论基础，为实现液态有机氢化物的储氢技术提供理论依据。

氢作为工业应用中最有效、清洁的二次能源载体之一，一直被认为是有潜在应用前景的车用替代燃料。然而，安全储存和输运氢气已成为严重制约其广泛工业化应用的瓶颈。目前，国内外成熟的氢储存技术主要是物理的方法，即高压气体压缩（70MPa）储氢、低温液化（-253°C）储氢和材料储氢的方法。高压压缩和液化储氢技术能耗高、安全性低，相比物理储氢方法、金属储氢和氢化物储氢，液态有机氢化物储氢具有较大的优势，适合长距离输运和安全使用，在未来的能源体系中液态有机氢化物储氢技术应用前景广阔。现在德国HT公司已经开始进入商业化运营模式，国内氢阳能源已成功中试并投资落地，但是，研发自主产权的成本低廉、高性能的催化剂技术仍有较大的挑战。本项目基于过渡金属碳化钼具有类铂的催化性能及在液态有机氢化物脱氢反应中有重要应用价值，通过设计和采用简单的方法制备了系列碳基碳化钼复合材料，调控了其结构和形貌，考察了制备工艺的影响，建立了碳结构、形貌和粒度等与其催化性能之间的构效关系，通过利用纳米碳结构和形貌的可调变性，有效改善了碳化物的催化脱氢性能，为研发结构与功能一体化的可替代贵金属催化剂提供了理论依据，为液态有机氢化物的储氢技术可提供重要参考。