科研与工业生产中微量及痕量二氧化碳的检测需要将其催化转化为甲烷，再利用气相色谱氢火焰离子化检测器进行定量分析。商用镍基甲烷化催化剂在400 ℃以上才具有较好的催化活性，然而在热力学上低温对二氧化碳甲烷化反应有利，并且低温反应可以减缓因一氧化碳歧化积碳和金属颗粒烧结导致的催化剂失活。论文全面、深入地研究了高H2/CO2比条件下二氧化碳的活化机制和甲烷化反应机理，基于微通道共沉淀法采用载体性质调控的策略合成了一系列可在300 ℃内实现二氧化碳全转化的镍基催化剂，总结了低温高活性镍基甲烷化催化剂的设计准则，为气相色谱领域新型高效镍基催化剂的开发和应用奠定了扎实的科学基础。采用微通道共沉淀法制备了高分散Ni/CeO2-CP催化剂，详细探究了金属载体相互作用对二氧化碳甲烷化反应活性和稳定性的影响。研究结果表明高分散Ni/CeO2-CP催化剂可在210 ℃实现二氧化碳全转化，展现出优于商用催化剂的稳态甲烷化活性与稳定性。通过一系列表征实验揭示了Ni-CeO2界面为二氧化碳甲烷化反应的催化活性位点，指出微通道共沉淀法在制备过程中强化了Ni与Ce的混合，形成了更多的Ni-CeO2界面参与二氧化碳活化，同时产生了粒径更小的活性金属纳米颗粒促进氢气解离活化、增强了活性H物种的供应，因此Ni/CeO2-CP催化剂展示出优异的低温活性和稳定性。通过少量Eu元素的掺杂构筑Ni/Ce0.9Eu0.1O1.95催化剂进一步提高了二氧化碳甲烷化稳态反应活性，系统揭示了Eu的引入对Ni/Ce0.9Eu0.1O1.95催化剂活性金属分散、界面位点数量、加氢物种比例以及二氧化碳甲烷化反应速率的影响。在气相色谱仪甲烷转化炉的脉冲反应条件下系统考察了载体性质对镍基催化剂二氧化碳甲烷化非稳态反应性能的影响。研究结果表明催化剂对二氧化碳的吸附太弱不利于低温反应活性的提升，而吸附过强则导致产物CH4峰存在展宽和拖尾等问题。在此基础上采用Al2O3对Ni/CeO2-CP催化剂进行改性，开发出性能优于安捷伦及岛津商用甲烷化催化剂的新型Ni/CeO2-Al2O3催化剂，在实现低温二氧化碳甲烷化的同时保证了气相色谱检测谱图中产物CH4峰的理想峰形。论文还基于上述催化剂设计了一种新型微量CO/CO2检测装置替代传统甲烷转化炉，在气相色谱氢火焰离子化检测器中实现了CO/CO2催化转化与CH4检测的同步进行。

The detection of trace carbon dioxide in scientific research and industrial production usually requires its catalytic conversion to methane, which is then quantitatively analyzed using a gas chromatograph with a flame ionization detector. Commercial nickel-based methanation catalysts show good catalytic activity only at temperatures above 400 °C, however, CO2 methanation reaction is thermodynamically favorable at lower temperatures, where the catalyst deactivation due to metal particle sintering and carbon deposition from CO disproportionation will be remarkably avoided. This thesis presents a comprehensive and in-depth study on the activation mechanism of CO2 and methanation reaction mechanism under the high H2/CO2 ratio condition. Based on a strategy to adjust the support properties, a series of nickel-based catalysts were synthesized by a co-precipitation method in microchannels, which can achieve complete conversion of CO2 within 300 °C. The design guidelines for low-temperature and high-activity nickel-based methanation catalysts were summarized, which laid a solid scientific foundation for the development and application of new types of high-efficiency nickel-based catalysts in the field of gas chromatography.Highly-dispersed Ni/CeO2-CP catalysts were prepared by the microchannel co-precipitation method, and the effect of metal-support interaction on the activity and stability of CO2 methanation reaction was investigated in detail. The results show that the highly-dispersed Ni/CeO2-CP catalysts can achieve complete conversion of CO2 at 210 °C, exhibiting better steady-state methanation activity and stability than commercial catalysts. Whereafter, a series of characterization experiments revealed that Ni-CeO2 interfaces are the catalytic active sites for CO2 methanation, and further indicated that the microchannel co-precipitation method could enhance the mixing of Ni and Ce during the preparation process, generating more Ni-CeO2 interfaces to participate in the activation of CO2, while decreasing the size of active metal nanoparticles to promote the dissociative activation of H2 and thereafter increase the supply of active H species. As a result, the Ni/CeO2-CP catalyst showed excellent low-temperature methanation activity and stability. By doping a small amount of Eu, the Ni/Ce0.9Eu0.1O1.95 catalyst was constructed to further enhance the steady-state CO2 methanation activity. The effect of Eu introduction on the dispersion of active metal, the number of interfacial sites, the ratio of intermediate species, and the rate of CO2 methanation of the Ni/Ce0.9Eu0.1O1.95 catalyst was systematically researched. The effect of support properties on the unsteady-state CO2 methanation performance of nickel-based catalysts was investigated under the pulse reaction condition, which is the same as the reaction atmosphere in a gas chromatograph methanation reactor. The results showed that weak adsorption of CO2 on the surface of catalysts was not conducive to the enhancement of the catalytic activity at low temperatures, while strong adsorption of CO2 led to problems such as broadening and trailing of the CH4 peak. On this basis, the Ni/CeO2-CP catalysts were modified with Al2O3 to develop a new Ni/Al2O3-CeO2 catalyst with better performance compared to the commercial catalysts purchased from Agilent and Shimadzu, which was able to achieve low-temperature CO2 methanation with ideal peak shape of CH4 in the chromatographic detection spectrum. A new trace CO/CO2 detection component based on the above catalyst was then designed to replace the conventional methanation reactor, enabling simultaneous CO/CO2 catalytic conversion and CH4 detection in a flame ionization detector embedded in a gas chromatograph.