CAREER: Single-Atom Alloy Nanocrystals for Catalyzing Sustainable Nitrogen Cycling

职业：用于催化可持续氮循环的单原子合金纳米晶体

• 批准号: 2143710
• 负责人: Huiyuan Zhu
• 金额: $ 59.29万
• 依托单位: Virginia Polytechnic Institute and State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-02-15 至 2023-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2143710&HistoricalAwards=false
• 关键词: CAREER; Single; Atom; Alloy; Nanocrystals

The industrial production of fertilizer – produced from ammonia (NH3) generated by the energy-intensive, fossil fuel-dependent Haber-Bosch (H-B) process - has disrupted the natural nitrogen cycle, resulting in groundwater pollution from nitrates (NO3-). The project utilizes electrochemistry to react nitrate compounds with hydrogen (derived sustainably from water) to manufacture NH3, while simultaneously decomposing the nitrate pollutants and restoring balance to the nitrogen cycle. Specifically, the research focuses on the discovery and design of catalysts that enable efficient nitrate-to-ammonia transformation driven by renewable electricity. Beyond the technical aspects, the project will train students from diverse groups at the interface of catalysis, chemistry, and engineering. The research will be integrated with educational and outreach efforts to illustrate the importance of sustainability in daily life while stimulating excitement for STEM amongst K-12 youth, especially those from low-income families. The electrochemical nitrate reduction reaction (NO3RR) offers a potentially attractive distributed NH3 production route, because it utilizes nitrate pollutants as the N-source, thus circumventing activation of the strong N≡N triple bond associated with the H-B process. The project will develop design strategies for single-atom alloy (SAA) electrocatalysts for the NO3RR and advance the fundamental understanding of both the catalytic active sites and the elementary mechanisms. The project is built on the central hypothesis that surface doping of Cu nanocrystals with isolated metal atoms (for example, Pt, Pd, Rh, or Ru) creates well-defined sites that activate water molecules and generate H-atoms that spill over to the Cu. The H-atoms hydrogenate N-species at low overpotentials and selectively tailoring of the binding strength of NO3RR surface intermediates through narrowly distributed d-states of single atoms for high-rate production of NH3, can potentially go beyond adsorption-energy scaling limitations. Catalyst synthesis, characterization, and electrochemical evaluation will be facilitated by advanced characterization techniques including operando surface-enhanced infrared absorption spectroscopy, differential electrochemical mass spectrometry, in-situ X-ray absorption spectroscopy, advanced electron microscopy, and computational tools such as density functional theory. The educational components of the project include (1) integrating research into the curriculum, (2) interdisciplinary student training, (3) involving diverse underrepresented students in science and engineering, and (4) implementing STEM-based outreach programs through the Center for Enhancement of Engineering Diversity at Virginia Tech and summer programs at Wonder Universe: A Children’s Museum. In addition, the newly launched Virginia Clean Energy and Catalysis Club will be leveraged as a platform to promote student training. The outreach plan also includes the development of an interactive play-based pedagogical platform, “Sustainable City in Minecraft,” that will provide young students the opportunity to design and construct a futuristic sustainable city.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.

化肥的工业生产--由依赖化石燃料的能源密集型哈伯-博世（H-B）工艺产生的氨（NH3）生产--破坏了自然氮循环，导致地下水受到硝酸盐（NO3-）的污染。该项目利用电化学将硝酸盐化合物与氢气（可持续地从水中提取）反应，以制造NH3，同时分解硝酸盐污染物并恢复氮循环的平衡。具体而言，该研究的重点是发现和设计催化剂，使可再生电力驱动的高效硝酸盐转化为氨。除了技术方面，该项目还将在催化，化学和工程的界面上培养来自不同群体的学生。 该研究将与教育和推广工作相结合，以说明可持续性在日常生活中的重要性，同时激发K-12青年，特别是低收入家庭青年对STEM的兴奋。电化学硝酸盐还原反应（NO3 RR）提供了一种潜在的有吸引力的分布式NH3生产途径，因为它利用硝酸盐污染物作为N源，从而避免了与H-B过程相关的强N-N三键的活化。 该项目将开发用于NO3 RR的单原子合金（SAA）电催化剂的设计策略，并推进对催化活性位点和基本机制的基本理解。该项目建立在中心假设的基础上，即用孤立的金属原子（例如，Pt，Pd，Rh或Ru）对Cu纳米晶体进行表面掺杂，产生明确的位点，激活水分子并产生溢出到Cu的H原子。H-原子在低过电位和选择性剪裁的NO3 RR表面中间体的结合强度通过窄分布的单原子的d-状态的NH3的高速率生产的N-物种，可以潜在地超越吸附能量缩放限制。催化剂的合成，表征和电化学评价将促进先进的表征技术，包括operando表面增强红外吸收光谱，差分电化学质谱，原位X射线吸收光谱，先进的电子显微镜和计算工具，如密度泛函理论。该项目的教育部分包括（1）将研究融入课程，（2）跨学科学生培训，（3）让科学和工程领域代表性不足的多元化学生参与其中，以及（4）通过增强中心实施基于STEM的外展计划弗吉尼亚理工大学工程多样性和Wonder Universe：A Children's Museum的夏季项目。此外，新成立的弗吉尼亚清洁能源和催化俱乐部将作为促进学生培训的平台。该推广计划还包括开发一个基于游戏的互动教学平台，“Minecraft中的可持续城市”，这将为年轻学生提供设计和建造未来可持续城市的机会。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。