室温下碳减排多孔金属有机框架材料的评估、筛选与反馈性设计合成

Global warming caused by greenhouse gases poses one of the most serious threats to the global environment ever faced in human history. The development of new capture technology to remove CO2 from atmosphere and industry emissions becomes a research hotspot in the field of energy & environment. Pressure Swing Adsorption on metal-organic frameworks (MOFs) for CO2 Capture and Sequestration (CCS) is a promising but challenging task. However, there are two crucial points need to be resolved. One is to set up new reliable evaluting criteria in screening adsorbents, instead of adsorption selectvity (S), the most common method but with the fallacy often occurred. Another is difficult to prepare the MOFs for CCS with high separation capacity and low regenerating energy. Our previous work showed dimensional breakthrough time is more reliable than the adsorption selectvity, but it is not straight because it needs the complicated calculation. This proposal will perform the analysis of the relationship between the breakthrough time and the adsorption data of pure composite gases for the large amount of MOFs reported for the CCS by statistical software SPSS, and then to give new straight, convenient and reliable criteria for the screening. Meanwhile, the project will conduct the synthsis of new MOFs based on the structural information of CO2-loaded MOFs with high separation performance, those structures could be obtained by x-ray single crystal diffraction, neutron diffraction or synchrotron radiation. It was well-known that the functional sites on the channel wall could help the MOFs to improve their CO2 separation capacity. With more dense of the functional sites, the MOFs show higher CO2 separation capacity, The stronger interaction between the functional sites and the adsorbates will bring the MOFs with more CO2 separation capacity, but also with the higher regenerationg penality. Here, a new approach was first proposed to realize the CO2 adsorbents with high separation capacity via optimizing the distribution of functional sites on the MOFs cage wall. In this case, the optimal cage would increase the CO2-CO2 adsorbate-adsorbate interaction which will bring the formation of high dense of CO2 clusters within the cavity. Once the goal is achieved, this kind of MOFs could show both high separation capacity and low regeneration penality as long as we simultaneously adjust the functional sites and their distribution on the wall. The porous MOFs assembled from the polyoxometalate or its analogue may provide an efficient model for the materials with the optimal cage and high dense of weak-interaction functional sites (OH groups). Metal-Silsesquioxane Frameworks (MSFs) may also give another kind of appealing CSS materials with high performance and thermal stability as they could provide high dense of open Cu sites and the cavity able to be optimized. Once the project completed, we may publish 8 - 10 peer-reviewed papers in decent journals and file 2 - 3 patents.

温室效应带来全球变暖是人类史上最为严峻的环境问题之一，研发新的CO2捕集CCS技术，降低大气中和工业排放的CO2已成为能源环境领域的研究热点。多孔金属有机框架(MOFs)的变压吸附法进行CCS是有潜力且极具挑战的工作，目前主要存在两点不足：单纯地以吸附选择性为标准无法真实衡量材料的CO2分离性能；现有吸附剂无法同时实现高分离能力和低再生能耗。我们的前期研究表明无维穿透时间可作为比吸附选择性更可靠的标准，但不够直观简便。本课题拟1)分析无维穿透时间与纯组分气体吸附数据的关系，凝练出可靠简便的评估标准；2) 以多酸及其有机多金属簇类似物，金属硅倍半氧烷框架等为研究体系，首创提出调节孔壁功能位点的位置分布,优化孔道结构，利用功能位点的导向作用，增大CO2-CO2吸附质间相互作用，提高CO2堆积密度，实现高稳定、高分离、低再生能的CO2捕集分离材料。预期申请专利2-3项，发表SCI论文8-10。

温室效应带来全球变暖是人类史上最为严峻的环境问题之一。金属有机框架(MOFs)的变压吸附法进行碳捕获是有潜力且极具挑战的工作，针对当前研究存在捕集量与再生能难以平衡的问题，我们设计合成了9个系列的MOF及复合材料，进行碳捕获研究：(1) 提出孔壁结构优化法，提高碳捕获综合性能，发现τbreak可作为优化参数评估多孔材料的碳捕获能力，获得捕获量160 cm3/cm3与记录值相当，但再生能只有34 kJ/mol的UTSA-16; (2) 提出氧化石墨烯(GO)包覆复合法，提升沼气脱碳综合性能，获得热稳定性为280 oC，脱碳选择性为114.4的 GO-UTSA-16; (3) 优化插层氧化石墨烯框架GOFs层间距与碳捕获性能的关系，发现层间距与UTSA-16的笼孔径相当时，CO2吸附量最高; (4) 提出反离子调控法，获得最高CO2存储密度0.955 g/cm3、低再生能仅18.8 kJ/mol的FJU-14-BF4; (5) 提出半刚性配体法，构筑多级孔结构MOFs，获得低再生能的碳捕获材料FJU-11; (6) 发展脉冲激光轰击技术，应用于多孔MOFs和MOFs@纳米粒子杂化材料的合成，获得高碳捕获量材料MgO@HKUST-1; (7) 提出晶面调节法，控制生长多级异质节的同晶杂化MOFs，获得室温下CO2吸附量为126 cm3/g的三级结构B-(B@A)-B; (8) 发展裸露氧受体法，分离50:50 乙炔/CO2混合气，获得分离容量44.13 cm3/g的FJU-22; (9) 观察不同分压下吸附CO2的FJU-40-NH2单晶结构，发现FJU-40-NH2可从空气中直接吸附CO2，孔壁氨基有时对吸附CO2不起作用。(10) 综合比较了近100种多孔材料，发现多孔MOFs比沸石在碳捕获综合性能方面更具优势。通过项目建设，培养硕士毕业生11名，主办国内会议2次，作邀请报告9次。在自然通讯，JACS，能源环境科学等发表论文26篇，两篇ESI 1%高引论文，申报专利6项，授权美国专利1项。多篇论文被Nature、Science等引用，1篇入选中国百篇最具影响力国际学术论文，Nature Asia高度评价我们的技术可为工业工程的CO2捕集分离提供新的可能。指导的本科生创业计划项目获“创青春”全国大学生创业大赛银奖。负责人入选青年千人计划和福建省“百人计划”。