Collaborative Research: Electrochemical Production of NH3 Using Proton-Conducting Ceramic Electrolytes

氨合成对于生产用于食品生产的肥料至关重要，沿着许多其他应用。目前生产氨的方法，即有100年历史的哈伯-博世工艺，是基于天然气的，消耗全球总能源的1-2%。这是一种高压、高温工艺，只有用于大规模生产才经济。在需要氨的地方直接用可再生形式的电力生产氨将具有显著的优势。本项目的目标是证明这可以以高效率完成。该项目将寻求开发一种电化学方法，使用质子传导陶瓷固体氧化物电化学电池从氢气和氮气中生产氨。中心假设是，大气压下，氨合成可以通过电化学驱动氢到催化表面上来实现，该催化表面通常受到高氮化物覆盖率的限制。该项目将寻求开发能够解离分子氮的电极催化剂，这是传统Haber-Bosch合成中的限速步骤，同时显示出低的氢复合活性，从而在电极表面实现高氢逸度。该项目将利用以前开发的用于固体氧化物燃料电池电极合成的渗透方法，该方法允许将各种材料用于电极。该项目将探索可以添加到电极中的混合电子-质子导体，以增强电化学反应可能发生的三相边界。电催化剂的选择将由互补的理论研究指导。将制作小规模示范电池。如果成功，该项目将对氨合成的能源需求和二氧化碳排放产生巨大影响。该项目将支持研究生和本科生进行研究，PI将开发以教师为主导的同伴指导计划，旨在提高STEM中代表性不足的本科生的保留率。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Ammonia synthesis is essential for production of fertilizers used in food production, along with many other applications. The present method for producing ammonia, the 100-year-old Haber-Bosch process, is based on natural gas and consumes 1-2% of total global energy. It is a high-pressure, high-temperature process that is only economical if used for large-scale production. There would be significant advantages to producing ammonia directly from renewable forms of electricity at the location where it is needed. The goal of this project is to demonstrate that this can be accomplished with high efficiency. This project will seek to develop an electrochemical method for production of ammonia from hydrogen and nitrogen using a proton-conducting, ceramic, solid-oxide electrochemical cell. The central hypothesis is that atmospheric-pressure, ammonia synthesis can be realized by electrochemically driving hydrogen onto catalytic surfaces that are normally limited by high nitride coverage. The project will seek to develop electrode catalysts that are able to dissociate molecular nitrogen, the rate-limiting step in conventional Haber-Bosch synthesis, while simultaneously showing low activity for hydrogen recombination so as to achieve a high hydrogen fugacity at the electrode surface. The project will take advantage of the infiltration methods previously developed for electrode synthesis in Solid Oxide Fuel Cells which allows a wide range of materials to be used for the electrodes. The project will explore mixed electronic-protonic conductors that can be added to the electrode to enhance the three-phase boundary where the electrochemical reaction can occur. The choice of electrocatalysts will be guided by complementary theoretical studies. Small-scale demonstration cells will be produced. If successful, the project will have a dramatic impact on the energy demand and carbon dioxide emissions from ammonia synthesis. The project will support both graduate and undergraduate students in conducting the research, and the PIs will develop faculty-led peer mentorship programs that aim to increase retention of underrepresented undergraduate students in STEM.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.