H+缓冲双极质子交换膜氢泵自耦合强化低氢CO2的分离与加氢

CO2 is greenhouse gas but potential chemical materials. Due to high thermal dynamical stability of CO2, hydrogenation of CO2 usually performs at high pressure and temperature to active CO2 and promote solubility and adsorption of H2. There are huge amount of CO2 refinery gases with low concentration H2, however, could not be utilized due to high energy intensity and complicated equipment of the present H2 separation methods. Most of them are burned just as fuel. Separation of anode and cathode processes by proton exchange membrane (PEM), electrochemical hydrogen pump (EHP) has the unique ability to couple multiple processes efficiently. Self-coupling insitu separation-hydrogenation with EHP is proposed in this project to synergistically improve efficiency of H2 and CO2 utilization, which is few reported in the literature. With H2/CO2 feedstock, H2 selectively and controllably dissociates at the anode into protons, and the concentrated CO2 are sent to the cathode. Protons transport through PEM to form insitu adsorbed hydrogen atoms on the cathode catalyst layer, and then hydrogenate with the adsorbed CO2 at ambient pressure and temperature. There are several keys to the self-coupling process, such as H2/CO2 adsorption and reaction competitions in the separation-hydrogenation coupling system and the control of hydrogenation potential by PEM. As solutions, proton buffering PEM, dynamic model of the EHP and self-coupling optimization method will be investigated and established in this project. As results, synergetic intensification mechanism of the self-coupling EHP will be interpreted. Effective conversion of CO2 to carboxylic acid based fuels will be reached to promote carbon recycling.

CO2是温室气体和潜在基础化工原料，热力学高度稳定。其非均相催化加氢需高温高压以活化CO2、提高H2溶解吸附。石化行业氢气短缺，但大量低氢CO2尾气因现有分离方法能耗高、设备复杂而难以利用，低浓度氢被浪费。电化学氢泵凭借质子交换膜阻隔阴、阳极电化学过程，是独特高效的过程耦合强化装置。本项目提出H+缓冲双极质子交换膜氢泵低氢CO2原位分离与加氢自耦合强化设计，低氢CO2气中H2在阳极高选择、可控解离为H+，传导至阴极形成高活性催化剂原位吸附氢，与阳极增浓后进入阴极CO2常温常压高效加氢。针对质子交换膜氢泵阴极电势调控、阴阳极原料及过程均自耦合流程中H2/CO2竞争吸附、竞争反应等关键问题，拟设计制备层层自组装H+缓冲双极膜，建立原位分离与催化加氢自耦合强化设计方法，揭示双极膜电极构建界面双电层、调控H+传递及自耦合氢泵分离与加氢协同增效机制，实现低氢CO2尾气向酸基燃料转化，国内外未见报道。

CO2是温室气体和潜在基础化工原料，热力学高度稳定。其非均相催化加氢需高温高压以活化CO2、提高H2溶解吸附。石化行业氢气短缺，但大量低氢CO2尾气因现有分离方法能耗高、设备复杂而难以利用，低浓度氢被浪费。本项目提出H+缓冲双极质子交换膜氢泵低氢CO2原位分离与加氢自耦合强化设计，低氢CO2气中H2在阳极高选择、可控解离为H+，传导至阴极形成高活性催化剂原位吸附氢，与阳极增浓后进入阴极CO2常温常压高效加氢。提出离子交换双极膜和层层自组装双极膜，在阴极侧构建双电层，解决电化学氢泵阴极电势调控和析氢竞争关键问题，使欧姆阻力显著降低（0.2Ω vs 3.84Ω），10h反应析氢效率稳定低于15%，加氢速率达到209 nmol.cm-2.s-1，远高于文献报道及本项目对比的缓冲层氢泵（~70 nmol.cm-2.s-1）；提出H2/CO2原位分离与加氢的电化学氢泵自耦合强化设计方法，建立动力学传质模型，嵌入HYSYS流程模拟软件，优化电化学氢泵-双膜分离耦合工艺流程，CO2转化率达到86.7%，甲酸电流效率最高为81.4%；提出电化学氢泵关键材料及过程强化系列方法，设计超强酸性硫酸酯、交错三醚三季铵等阴阳离子交换基团及其接枝策略，设计电纺纤维沿膜厚直通取向、整体氢键网络等离子交换膜拓扑结构，设计原子分散活性位点高效CO2 电还原催化剂，建立局域配位结构与电流效率间构效关系。研究成果具有我国自主知识产权，有助于建立我国在CO2高效资源化领域的研究领先地位，满足我国节能减排、碳资源循环利用重大需求。. 发表高水平SCI/EI学术论文 36 篇，授权/申请国家发明专利 15/10 项，参加国际/国内学术会议 15/15 人次，开展国际交流互访 9 人次，培养博/硕士研究生 10 /20 名，培养青年教师获2018年度侯德榜化工科学技术青年奖，获批中国石油和化学工业联合会创新团队，圆满完成项目的研究目标。