EAGER: Electrochemical Reactor for Spontaneous Power Generation and CO2 Capture

1005303 Mustain该项目的目的是测试以下假设：i）具有烧绿石结构的碱土氧化物可以在碱性电化学反应器中选择性地将O2和大气CO2还原为CO 3 -2; ii）与氢氧化物循环操作相比，使用碳酸根阴离子操作反应器减少了最先进的阴离子交换膜的降解;和iii）H2和甲醇可以在具有碳酸根阴离子的Pt表面上电化学氧化。这些基本发现将允许开发在碳酸盐阴离子循环上操作的室温电化学反应器，与质子和氢氧化物交换膜燃料电池相比，其具有降低的成本和增加的耐久性。除了产生能量，这种细胞还充当CO2？泵？和净化装置。本论文研究了三种烧绿石结构（A_2B_2O_7）氧还原电催化剂：Ca_2Pt_2O_7、Ca_2Ru_2O_7和Ca_2W_2O_7。选择钙基氧化物是由于其根氧化物CaO的已知表面碱性，这将允许CO2优先于H2O吸附在催化剂表面上。烧绿石结构的氧化物避免了碱土金属氧化物的常见缺陷，包括低电子电导率和表面钝化物质的形成。Pt、Ru和W？B？将研究金属，因为它们在碱性介质中活化分子氧的能力。所得催化剂将通过SEM/EDS、XRD、BET和XPS充分表征。Pt电催化剂将在阳极，其中两种常见的燃料，H2和CH 3OH，将被氧化，其动力学研究。所有电化学测量将在定制的三电极电池中进行。最后，在浓KOH和HCO 3-/CO 3 - 2存在下，研究了六种市售阴离子交换膜的化学稳定性和离子电导率。研究结果将为阴极氧化物的表面吸附和电子转移行为以及电化学反应器的设计，特别是电化学界面的构建、维护和稳定提供信息。此外，PI将使用单独的组件来构建一个实验室规模，5平方厘米的碳酸盐循环电化学反应器上运行，并证明其在各种操作条件下的性能。康涅狄格大学的一个研究小组。这将：i）涉及研究活动的本科生; ii）培训研究生; iii）允许动手研究的PI？通过NSF赞助的康涅狄格大学的Joules-Fellows项目，为哈特福德公立学校的一名中学教师提供实验室; iv）在档案期刊上传播科学进步。研究和教育活动将促进发现和理解，同时促进多层次的教学，培训和学习。此外，这些结果可能对许多重要系统产生深远的影响，包括：燃料电池，电池，生物柴油油的异构酯交换，电化学辅助碳封存，减少汽车污染预防和水处理中的一氧化二氮和电解。在这方面的成功可以催化电化学能源发电装置的理念的变革性转变，恢复公共、私人和立法对替代能源技术的支持，并产生具有成本效益的环境绿色能源，具有在21世纪及以后实现净负二氧化碳足迹的潜力。

1005303Mustain The objective of this project is to test the hypotheses that: i) alkali earth oxides with the pyrochlore structure can selectively reduce O2 and atmospheric CO2 to CO3-2 in an alkaline electrochemical reactor; ii) operating the reactor with carbonate anions reduces the degradation of stateof- the-art anion exchange membranes compared with operation on the hydroxide cycle; and iii) H2 and methanol can be electrochemically oxidized on Pt surfaces with carbonate anions. These fundamental discoveries will allow for the development of a room temperature electrochemical reactor operating on the carbonate anionic cycle with reduced cost and increased durability compared to both the proton and hydroxide exchange membrane fuel cells. In addition to producing energy, this cell also acts as a CO2 ?pump? and purification device. The anode effluent CO2 and water can be separated and either utilized in chemical processing or sequestered.In this work, three pyrochlore structured (A2B2O7) oxygen reduction electrocatalysts will be tested: Ca2Pt2O7, Ca2Ru2O7 and Ca2W2O7. A calcium-based oxide was selected due to the known surface basicity of its root oxide, CaO, which will allow for the preferential adsorption of CO2 over H2O on the catalyst surface. The pyrochlore structured oxide avoids common pitfalls of alkali earth oxides, including low electronic conductivity and the formation of surface passivating species. Pt, Ru and W ?B? metals will be investigated because of their ability to activate molecular oxygen in alkaline media. The resulting catalysts will be fully characterized by SEM/EDS, XRD, BET and XPS. Pt electrocatalysts will be investigated at the anode, where two common fuels, H2 and CH3OH, will be oxidized and their kinetics examined. All electrochemical measurements will be conducted in a custom-built three electrode cell. Finally, the chemical stability and ionic conductivity of six commercially available anion exchange membranes will be investigated in the presence of both concentrated KOH and HCO3-/CO3-2.The results will yield information regarding surface adsorption and electron transfer behavior of the cathode oxides, information regarding electrochemical reactor design, specifically the construction, maintenance and stabilization of the electrochemical interface. Also, the PI will use the individual components to construct a laboratory scale, 5 cm2 electrochemical reactor operating on the carbonate cycle and demonstrate its performance under various operating conditions.Broader ImpactsThe educational objective is to establish a teaching and learning chain related to electrochemical science and engineering within the PI?s group at the University of Connecticut. This will: i) involve an undergraduate student in the research activities; ii) train a graduate student; iii) permit hands-on research in the PI?s laboratory for a Hartford Public School secondary school teacher through the NSF-sponsored Joules-Fellows program at the University of Connecticut; and iv) disseminate the scientific advances in archival journals.The research and educational activities will enhance discovery and understanding while promoting teaching, training and learning across multiple levels. Also, the results could have far reaching impact on many important systems including: fuel cells, batteries, heterogeneous transesterfication of oils for biodiesel, electrochemically assisted carbon sequestration, reduction of nitrous oxides in automotive pollution prevention and water treatment and electrolysis. Success in this regard could catalyze a transformative shift in philosophy regarding electrochemical energy generation devices, renew public, private and legislative support for alternative energy technologies and yield a cost-effective, environmentally green energy source with the potential for a net negative CO2 footprint for the 21st century and beyond.