Nanoscale Transition Metal Pnictides: Materials by Design

纳米级过渡金属磷化物：设计材料

• 批准号: 1361470
• 负责人: Stephanie Brock
• 金额: $ 42万
• 依托单位: Wayne State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1361470&HistoricalAwards=false
• 关键词: Nanoscale; Transition; Metal; Pnictides; Materials

NON-TECHNICAL SUMMARYWith support from the National Science Foundation, Division of Materials Research, the development of new materials and knowledge for the design of cooling devices will be achieved. Air conditioning and refrigeration is a part of daily life, with air conditioning consuming 5%, and commercial refrigeration up to 20%, of energy output. The conventional process of refrigeration (gas compression and expansion) has limited efficiency, and the refrigerants are often ozone-depleting and/or Greenhouse gases, raising concerns whenever inevitable leaks arise. A more energy efficient (by up to 50%) and environmentally friendly process is magnetic refrigeration, where application of a magnetic field to a magnetocaloric (MC) material results in heat emission, and removal of that field results in heat absorption, effectively acting as a heat pump. Traditional MC materials are based on the rare-earth metal gadolinium, which suffers from poor efficiency near room temperature and is prohibitively expensive. In this NSF-DMR supported project a rational approach will be exploited for the development of MC materials based on nanoparticles comprising earth-abundant elements. The effect of nanoparticle composition and size, as well as interactions between particles on magnetic properties will studied en route to developing inexpensive and efficient devices for magnetic refrigeration. Over the course of the project, graduate and undergraduate students will develop critical thinking and technical skills, as well as hands-on experience with cutting-edge techniques, for developing the next generation of advanced technologies. The project will also introduce Detroit-area middle and high school girls, many of whom are underrepresented minorities, to materials science through the GO-GIRL (Gaining Options-Girls Investigate Real Life) Material Girls outreach project.TECHNICAL SUMMARYWith support from the National Science Foundation, Division of Materials Research, the principal investigator will produce functional transition metal pnictide (pnicogen = Group 15 element) nanoparticles and assemblies, focusing on materials for magnetic refrigeration (MR). Transition metal pnictides comprise a large but relatively underexplored class of materials, despite having properties that span the energy landscape. These materials are being investigated in thermoelectric devices (waste heat conversion), batteries (energy storage), catalysis (fuel processing), and magnetic refrigeration (climate control). Many of the envisioned advances in these technologies presume the ability to control the physical dimensions of the materials on the nanoscale, a significant challenge. Moreover, confinement to nanoscale dimensions impacts properties in sometimes unexpected ways (intraparticle effects), as does integration/assembly (interparticle effects). These issues have hampered the development of transition metal pnictide nanoparticles to address key technological problems. MR is based on the absorption and release of energy during a magnetic transition (the magnetocaloric effect), and is 50% more efficient than traditional gas compression/expansion systems and more environmentally friendly, as it does not exploit ozone-depleting or greenhouse gases. Heretofore inaccessible but promising nanoscale phases for MR will be produced by exploiting ion-exchange routes and direct syntheses, targeting Fe-doped Mn pnictides (Aim 1). On a parallel track, anion (P, Sb) doped MnAs nanoparticles will be synthesized and detailed structure-property-size correlations established (Aim 2). This information will be used to narrow the parameter space for production of new materials in Aim 1 so as to target the most promising phases and sizes. The final parallel investigation (Aim 3) will focus on integration and assessment of interparticle interactions in known phases, subsequently moving to new phases as materials from Aims 1 and 2 become available.

非技术概要在国家科学基金会材料研究部的支持下，将实现冷却装置设计的新材料和知识的开发。空调和制冷是日常生活的一部分，空调消耗能源输出的5%，商业制冷高达20%。传统的制冷过程（气体压缩和膨胀）效率有限，而且制冷剂通常会消耗臭氧层和/或温室气体，一旦发生不可避免的泄漏，就会引发人们的担忧。一种更节能（高达 50%）且环保的工艺是磁制冷，其中将磁场应用于磁热 (MC) 材料会导致热量散发，而去除该磁场会导致热量吸收，从而有效地充当热泵。传统的MC材料基于稀土金属钆，其在室温附近的效率很低，而且价格昂贵。在这个 NSF-DMR 支持的项目中，将采用合理的方法来开发基于包含地球丰富元素的纳米粒子的 MC 材料。 将研究纳米粒子的组成和尺寸以及粒子之间的相互作用对磁性的影响，以开发廉价且高效的磁制冷装置。 在该项目的过程中，研究生和本科生将培养批判性思维和技术技能，以及尖端技术的实践经验，以开发下一代先进技术。 该项目还将通过 GO-GIRL（获得选择 - 女孩调查现实生活）材料女孩外展项目，向底特律地区的初中和高中女生（其中许多是少数族裔）介绍材料科学。技术摘要在国家科学基金会材料研究部的支持下，首席研究员将生产功能性过渡金属磷化物（pnicogen = 第 15 族元素）纳米颗粒和组件，重点关注磁性材料 制冷（MR）。尽管过渡金属磷化物具有跨越能源领域的特性，但它仍然是一类规模较大但相对尚未开发的材料。这些材料正在热电装置（废热转换）、电池（能量存储）、催化（燃料加工）和磁制冷（气候控制）中进行研究。这些技术的许多预期进步都假定能够在纳米尺度上控制材料的物理尺寸，这是一个重大挑战。此外，纳米级尺寸的限制有时会以意想不到的方式影响性能（颗粒内效应），集成/组装（颗粒间效应）也是如此。这些问题阻碍了过渡金属磷族化物纳米颗粒的开发以解决关键技术问题。 MR 基于磁转变过程中能量的吸收和释放（磁热效应），比传统气体压缩/膨胀系统效率高 50%，并且更环保，因为它不利用消耗臭氧层或温室气体。迄今为止难以获得但有前途的 MR 纳米级相将通过利用离子交换途径和直接合成来生产，目标是铁掺杂锰磷族元素（目标 1）。在平行轨道上，将合成阴离子（P，Sb）掺杂的 MnAs 纳米颗粒，并建立详细的结构-性能-尺寸相关性（目标 2）。该信息将用于缩小目标 1 中新材料生产的参数空间，以瞄准最有希望的相和尺寸。最终的并行研究（目标 3）将重点关注已知相中颗粒间相互作用的集成和评估，随后随着目标 1 和 2 中的材料变得可用而转向新阶段。