氮掺杂硅基多孔材料的CO2吸附性能研究

The pressure swing adsorption (PSA) for CO2 capture has received increasing attention due to the low energy consumption, the ease of handling, the longevity of solid adsorbents, and no corrosiveness. The key of the PSA for CO2 adsorption is to obtain high-performance CO2 porous adsorbents for highly efficiently capturing CO2. This project proposed here about CO2 capture using porous solid adsorbents will develop a series of nitrogen-doped solid basic CO2 porous adsorbents by the nitridation of several porous materials having different pore sizes, such as microporous zeolites, microporous/mesoporous bimodal zeolites, and mesoporous silicas, at high temperatures. The microstructural change of porous materials before and after the nitridation as well as its effect on the sorption properties of porous materials will be analyzed. Also the CO2 adsorption-desorption performance of the nitrided porous materials will be studied using the PSA. The purpose of this project is to disclose the interaction and intrinsic physicochemical mechanism of the CO2 capture performance and the microstructure as well as the nitrogen contents of the nitrogen-doped porous materials, build the structure-activity relationship of the optimum CO2 adsorption performance corresponding to the optimum nitrogen content, pore size, etc, and accordingly determine the optimum nitridation parameters. By employing the optimum nitridation process, the nitrogen-incorporated porous materials with the excellent CO2 adsorption performance (high adsorption capacity, high adsorption ratio of CO2/N2, etc.) will be desirably prepared. The results of this project will be of much importance to achieve the efficient reduction of CO2 emission, improve the environmental quality, and promote the development of low-carbon economy. At the same time, the investigation will also provide the scientific help for the practical application of capturing CO2 using the PSA.

变压吸附法回收CO2技术具有低能耗、工艺简单、长寿命、无腐蚀等特性,受到越来越多的关注。变压吸附法的关键在于获得高性能多孔吸附剂以高效捕获CO2。本项目以多孔吸附剂回收CO2 为研究对象，选择几种不同孔径的多孔材料（微孔沸石、微孔介孔双孔沸石和介孔SiO2）为原料，结合高温氮化法制备一系列氮掺杂固体碱性CO2多孔吸附剂，研究材料氮化前后的结构变化及其对吸附性的制约关系，并利用变压吸附法研究合成产物的CO2吸附-脱附特性。本项目研究将揭示含氮多孔材料的CO2吸附性能与微结构和氮含量之间的关联及内在物理化学机制，建立CO2高效吸附性能与对应的最佳氮含量和孔径结构间的构效关系，并确定优化的氮化参数，获得具有高CO2吸附性能（高吸附值、高选择性等）的氮掺杂多孔吸附剂。项目的研究成果对于实现CO2减排、改善环境质量、促进低碳经济发展具有重要意义，同时也可为变压吸附法回收CO2的实际应用提供科学依据。

随着人口的快速膨胀、对能源消耗的爆炸性增长、以及越来越多的国家进入工业化发展阶段，可以预见在未来将要消耗更多的化石燃料，因此化石燃料燃烧排放的CO2还将对气候变暖起主导作用。本项目以CO2的吸附与存储为研究对象，采用多种手段发展一系列高性能CO2吸附材料。采用氨气氮化法制备一系列N掺杂介孔SiO2材料，最高氮含量为20.1%，N的掺杂明显提升了CO2吸附能力，其在常温常压下对CO2吸附能力为0.51 mmol/g，这主要归功于孔壁表面存在大量的氨基官能团，有利于CO2酸性分子的化学吸附；采用浸渍法制备介孔基有机无机SBA-15/PEI复合材料，其最高CO2吸附能力为1.78 mmol/g；利用一步聚合活化法制备了N修饰多孔碳材料，表现出高的CO2吸附能力2.86 mmol/g（室温中）；并研究了一些不同N掺杂碳材料对电催化氧还原的反应能力，发现这类材料中吡啶N具有较高的电催化氧还原能力，这主要是因为N原子的引入导致其周边碳原子的电荷不匹配，从而提高了电催化能力。