基于应力调控和分子模拟的低温CO2甲烷化催化剂的制备及构效关系研究

The large consumption of fossil energy has led to a sharp increase in CO2 emissions and a growing greenhouse effect, bringing severe challenges to the global climate and ecological environment. How to use CO2 effectively has become an urgent problem to be solved.How to use CO2 effectively has become an urgent problem to be solved. CO2 methanation is considered to be the most practical and effective route for CO2 recycling technology. It can not only reduce the concentration of CO2 in the atmosphere, but also produce clean natural gas (CH4) and alleviate domestic energy pressure.Nickel based catalysts are often used in the research of CO2 methanation due to their excellent catalytic performance and low price.At present, CO2 methanation on Ni based catalysts often requires high temperature (>573K), which is not necessary for this strong exothermic reaction.This project proposes to design a low-temperature CO2 methanation catalysts with high activity and CH4 selectivity based on the combination of strain regulation and molecular simulation.In addition, the effects of catalysts on CO2 adsorption, activation and catalytic selectivity will be well investigated. Finally, the reaction mechanism will be explored through conventional and in-situ characterization, which can provide a scientific basis for rational design and optimization of low-temperature CO2 methanation nickel catalysts.

化石能源的大量消耗使CO2的排放量急剧增加，温室效应日益严重，对全球气候和生态环境提出了严峻挑战。如何有效利用CO2成为亟待解决的问题。CO2甲烷化被认为是CO2循环再利用技术中最实用有效的路径，其不仅可以减少环境中CO2浓度，还可以生产洁净的天然气资源，缓解国内能源压力。镍催化剂由于其优异的催化性能和低廉的价格常被用于CO2甲烷化的研究。目前镍催化剂上进行CO2甲烷化往往需要较高温度（>573K），而这对强放热的CO2甲烷化反应本身是不必要的。因此，发展高效低温CO2甲烷化催化剂具有一定的学术意义和经济价值。本项目提出将应力调控和分子模拟相结合，设计出低温（<473K）高活性高选择性的急冷骨架镍催化剂，探究催化剂对CO2吸附、活化以及甲烷选择性的影响机制，通过常规及原位表征揭示反应机理，为低温CO2甲烷化反应镍催化剂的理性设计与优化提供科学依据。

CO2甲烷化被认为是CO2循环再利用技术中最实用有效的路径，其不仅可以减少环境中CO2浓度，还可以生产洁净的天然气资源，缓解国内能源压力。Ni催化剂由于其优异的催化性能和低廉的价格常被用于CO2甲烷化的研究，但目前仍存在反应温度较高，低温反应活性较低等问题。发展高效低温CO2甲烷化催化剂具有一定的学术意义和经济价值。本项目提围绕催化剂设计、构效关系和反应机理进行研究，主要研究结果为：1.本项目通过设计了通过急速冷却法制备了急冷骨架镍RQNi催化剂，其在低温（473 K）甲烷化反应中比活性和甲烷选择性分别为4.85molCO2molNi−1h−1和99.5%，为非急冷RaneyNi催化剂的5.1倍，表征及理论计算表明Ni-Ni晶格膨胀能有效降低甲烷化反应的活化能，进而提高反应活性。2. 研究不同冷却速率的急冷骨架镍RQNi1-RQNi5催化剂在低温CO2甲烷化反应中的反应活性、甲烷选择性以及稳定性的影响，并通过表征和理论计算进一步阐明了RQNi催化剂与低温CO2甲烷化的构效关系。3. 随着RQNi系列催化剂Ni-Ni间距的增加，该反应的决速步骤（C-O键的断裂）在催化剂上的活化能垒呈先降低后升高规律，其中RQNi2催化剂具有最低的活化能垒，与反应活性相一致。本项目围绕研究内容，探究催化剂对CO2吸附、活化以及甲烷选择性的影响机制，通过常规及原位表征揭示反应机理，为低温CO2甲烷化反应镍催化剂的理性设计与优化提供科学依据。