CO直接加氢合成乙醇Cu-Co双金属催化体系关键基础问题研究

Development of process of direct synthesis to ethanol from syngas based on coal，natural gas and biomass is highly desired. The objectives of this project are to design Cu-Co catalyst with high performance. The method of experiment(model catalyst)―theory(molecular simulation and in situ spectroscopy)－experiment was used to design Cu-Co catalyst with high stability and selectivity. In the project, Cu-Co was confined in porous supports to aviod aggregation and sintering problem, and activity, selectivity and stability was improved based on shape selectivity of support. Combining molecular simulation and operando spectroscopy, the effects of support, promoters and preparation methods on catalyst stability and selectivity were systematically studied. First, the relationship between key intermedites and catalyst structure will be determined. Next, micromodel of catalysts was constructed to understand the effect of support and promoters on active metal. Finally, the general rules of promoters affecting reaction network will be obtained. On the basis of molecular understanding of the reaction mechanism, Cu-Co catalysts with high stability and selectivity will be developed and preparation methods will be optimized for mass production and industrial application.

以煤炭、天然气和生物质为原料，开发合成气制备乙醇工艺具有良好的发展前景。本项目以科学设计高性能Cu-Co双金属催化剂为主体，采用"实践（模型催化）?理论（分子模拟和原位光谱表征）?实践（传统催化）"的研究方法，设计高稳定性和选择性的Cu-Co催化剂。运用先进的催化剂设计理念，将Cu-Co纳米颗粒限域在特定结构的多孔载体中，避免了催化剂纳米颗粒的聚集和烧结问题，并利用载体择形性，提高催化剂活性、选择性和稳定性。结合分子模拟和现场原位表征技术研究催化剂载体、助剂及制备方法对催化剂稳定性和选择性影响规律。确定反应物及其中间态吸附物种与催化剂结构匹配关系；明确载体和助剂对活性金属活化与稳定作用微观模型，探索助剂改变反应网络中各种反应平衡规律。通过对分子层面CO加氢催化反应机理理解，指导CO加氢Cu-Co系高稳定性和选择性催化剂的设计，为催化剂规模生产和工业应用奠定基础。

以煤炭、天然气和生物质为原料，开发合成气制备乙醇工艺具有良好的发展前景。本项目以科学设计高性能Cu-Co双金属催化剂为主体，采用“实践（模型催化）↔理论（分子模拟和原位光谱表征）↔实践（传统催化）”的研究方法，设计高稳定性和选择性的Cu-Co催化剂。通过XRD，XAS和Raman等表征技术研究铜和铜钴催化剂在合成气直接制备高碳醇性能差异，并阐明Cu对Co活性中心起源和高碳醇反应机理的影响。采用原位XRD，原位Raman和CO-DRIFTS对催化剂还原过程及表面微观结构进行剖析，结果表明被Cu覆盖的CuCo双金属颗粒对醇类的生成起关键作用。并在真实反应条件下测定了反应的本征动力学。通过动力学研究和密度泛函理论可知：（1）Cu的加入削弱了CO的吸附和HCO物种的解离, 降低了表面CHx物种数量；（2）Cu可以控制表面Co颗粒的大小，抑制CHx的插入。最后，研究了不同Co负载量的Co/CeO2催化剂在合成气直接制C1-C5醇的性能，研究表明Co-Coδ+界面是醇类产物生成的活性中心。