碳负载Ni-Cu双金属催化剂及其低温低压下活化二氧化碳的机理研究

Carbon dioxide activation is the rate-determining step in its hydrogenation to methanol reaction. The high activation barrier of CO2 requires very high reaction temperature and pressure. In order to lower the reaction temperature and pressure, the nano-sized Ni-Cu bimetallic particles supported on modified carbon material was synthesized in this project. A serious of methods will be introduced to modify the carbon support, then the Ni-Cu nano-particles will be loaded in the modified support, followed by the detailed exploration of the activation property of the catalysts. The catalysts will be characterized by the means of XRD, FESEM, HRTEM, in-situ FTIR, Chemisorption and N2-physisorption, etc. The effects of the modification methods on the morphology and distribution of the nano-particles, the interaction mechanism of the carbon atoms and the functional groups will be thoroughly investigated. The interaction strength and between the catalyst support and nano-particles will be obtained. Moreover, the activation mechanism of the carbon dioxide will be determined by theoretically calculation based on the catalysts' performances. To solve the key scientific issue in the carbon dioxide hydrogenation to methanol process, this project will focus on the three aspects: the controllable preparation, the formation mechanism and the activation property. The successful implemantation of this project will provide the carbon dioxide industrialization process with theoretical support for the carbon dioxide utilization at lower temperature and pressure.

二氧化碳活化是其加氢制甲醇的限制性环节，针对该过程活化能垒高，反应条件为高温高压的问题。本项目拟合成能在低温低压条件下活化二氧化碳的碳材料负载 Ni-Cu纳米双金属催化剂。拟采用不同化学方法对碳载体进行改性，再在碳载体上负载Ni-Cu纳米双金属，明确该催化剂在低温低压下活化二氧化碳的性能。借助X-射线衍射分析，场发射扫描电镜，高分辨透射电镜，原位红外光谱分析，化学吸附分析，N2-吸附脱附等温线分析等先进测试手段，探明官能团与碳原子的相互作用机制；厘清载体改性方法与纳米金属的形貌及分布的关系，获得催化剂载体与纳米金属颗粒的相互作用强度。辅助于理论计算，明确催化剂活化二氧化碳的性能及机理，为低温低压下活化二氧化碳提供理论依据和技术支撑。本项目将着重从“可控制备、形成机理、活化性能”三方面解决二氧化碳加氢制甲醇的关键科学问题，为我国二氧化碳能源化利用工业化进程奠定理论基础

CO2具有稳定的化学性质，较高的吉布斯自由能。因此，CO2活化是其能源化转化的关键步骤。本基金课题制备了石墨烯及改性石墨烯负载的Ni-Cu单双金属催化剂，研究了催化剂与CO2活化之间的构效关系。首先，通过FTIR和Raman表征深入对比分析了不同改性处理后载体的微观结构和官能团的变化。探讨了Ni-Cu金属离子的引入与含有不同种类和数量官能团载体的相互作用规律。通过XRD和XPS表征研究了不同载体上金属离子价态及存在形式的变化规律，建立了具有不同种类和数量官能团载体和Ni-Cu金属离子之间相互作用的模型。根据TEM和SEM表征摸清了金属纳米粒子在不同载体上的分布规律和相互作用机理。最后，采用TG-DSC和CO2 -TPD深入研究了不同石墨烯载体负载Ni-Cu金属催化剂的CO2活化及吸附性能，建立了该类催化剂活化CO2的特征关系。结合第一性原理计算发现了在石墨烯中引入缺陷和Ni/Cu原子会改变石墨烯的结构，提高CO2的吸附能力，增强CO2与石墨烯之间的电荷交换能力，与实验中表征的结果具有一致性。本基金课题首次尝试调控了碳载体与Ni-Cu纳米金属的相互作用情况，探索了纳米Ni-Cu在载体中的分布规律和对CO2的吸附能力，并建立了分布规律与催化活性的构效关系。为推进大规模低成本地工业化利用CO2提供了理论基础和科学依据。