NSF-DFG Echem: Electrochemically enhanced low-temperature catalytic ammonia synthesis

NSF-DFG Echem：电化学增强低温催化氨合成

• 批准号: 460038541
• 负责人: Professor Dr. Olaf Deutschmann
• 金额: --
• 依托单位: Europäisches Institut für Energieforschung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/460038541?language=en
• 关键词: NSF; DFG; Echem; Electrochemically; enhanced

As an alternative to centralized Haber-Bosch, small-scale distributed ammonia synthesis has great value. Avoiding very high pressures reduces high capital cost, and electrochemical promotion potentially enables carbon-free ammonia. Foregoing research was based on polarized protonic-ceramic electrochemical cells, with either steam electrolysis or methane reforming on the anode, a proton-conducting ceramic membrane, and ammonia synthesis on the cathode. Because equilibrium ammonia synthesis rates decrease greatly as temperature increases, low-temperature (e.g., T< 450 °C) catalysis is needed. However, even with the best catalysts, synthesis is greatly reduced by kinetic limitations below about 500 °C. Protons likely play a significant role in catalysis. Practical protonic-ceramic electrochemical cells usually operate between 500 and 700 °C. Electrochemical cells do produce ammonia, but at low rates. The proposed approach here is different. We will study the direct electrochemical activation of a novel catalyst support to increase synthesis rates greatly at low temperatures where the process is kinetically limited by N2 activation. This objective of the joint project of Karlsruhe Institute of Technology (KIT) and Colorado School of Mines (CSM) is to develop and demonstrate electrochemical enhancement that enables low-temperature and low-pressure ammonia synthesis. Nanophase Ru is dispersed on a proton-conducting BCZY support. Directly polarizing the catalyst structure with an electric field decreases the kinetically limited barrier for N2 activation. Although the proposed research is scientifically fundamental, it has great technology potential for cost-effective distributed production of ammonia. The research focuses on postulating, modeling, and validating proposed chemical behaviors. The electrical field is expected to reduce rate-limiting N2 dissociation barriers via two synergistic mechanisms:1. Electrical fields affect the proton-conducting BCZY support, enabling H2 dissociation to form protons that can activate gas-phase N2, directly forming desired surface adsorbates such as NH(BCZY).2. Fields in the range of 0.1 to 1.0 V/Å on dispersed nano-Ru also reduce the nitrogen activation barrier. Based on our validated reaction mechanisms for Ba-promoted Ru/YSZ, simulations show that reducing the N2 dissociation energy by 10 kJ mol-1 will increase the ammonia formation rate by an order of magnitude.Achieving the proposed objectives relies on the combined, complementary, and unique expertise of the partners in the context of heterogeneous catalysis, materials synthesis, characterization and process demonstration (KIT) and physically based modeling of the electrochemistry, charged-defect transport, and catalysis (CSM).

作为集中式Haber-Bosch的替代方案，小规模分布的氨合成具有很高的价值。避免极高的压力降低了高资本成本，电化学促进可能会促进无碳氨。上述研究基于极化质子陶瓷电化学细胞，阳极上的蒸汽电解或甲烷重整，质子导电的陶瓷膜和阴极上的氨合成。由于氨合成速率随着温度的升高而降低，因此需要低温（例如，t <450°C）催化。但是，即使使用最佳催化剂，动力学限制大大降低了约500°C。质子可能在催化中起重要作用。实用的质子陶瓷电化学细胞通常在500至700°C之间工作。电化学细胞确实会产生氨，但速率低。这里提出的方法是不同的。我们将研究新型催化剂支持的直接电化学激活，以提高合成速率，在该过程受到N2激活的限制的低温下。 Karlsruhe技术研究所（KIT）和科罗拉多州矿业学院（CSM）的联合项目的这一目标是开发和展示电化学增强功能，从而实现低温和低压氨合成。纳米相RU分散在质子导向的BCZY支持上。用电场直接使催化剂结构偏振会降低动力学上有限的N2激活屏障。尽管拟议的研究在科学上是基本的，但它具有巨大的技术潜力，可用于具有成本效益的氨分布生产。该研究的重点是假设，建模和验证提议的化学行为。预计电场将通过两种协同机制降低限制速率的N2解离屏障：1。电场影响质子导向的BCZY支持，使H2解离以形成可以激活气相N2的质子，直接形成所需的表面吸附剂，例如NH（BCZY）.2。分散的纳米ru的0.1至1.0 v/Å的范围也减少了氮激活屏障。 Based on our validated reaction mechanisms for Ba-promoted Ru/YSZ, simulations show that reducing the N2 dissociation energy by 10 kJ mol-1 will increase the ammonia formation rate by an order of magnitude.Achieving the proposed objectives relies on the combined, complete, and unique expertise of the partners in the context of heterogeneous catalysis, materials synthesis, characterization and process demonstration (KIT) and physically based modeling of电化学，收费缺失的运输和催化剂（CSM）。