Thin Film Metal Ferrite Spinels for Solar-thermochemical Redox Cycles to Split Water

用于太阳能热化学氧化还原循环分解水的薄膜金属铁氧体尖晶石

• 批准号: 0966201
• 负责人: Alan Weimer
• 金额: $ 30.12万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-15 至 2015-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0966201&HistoricalAwards=false
• 关键词: Thin; Film; Metal; Ferrite; Spinels

0966201WeimerThere is a need to develop cost-effective, renewable energy processes for the production of clean fuels such as hydrogen gas (H2). If H2 can be obtained cost effectively by the splitting of water using concentrated sunlight, then it is possible to operate a fuel cell using renewable H2 to generate electricity or to synthesize other fuels based on renewable H2. Intellectual Merit The overall objective of the proposed research is to develop a fundamental understanding of the ability of metal ferrite spinels to split water into hydrogen gas via a solar-thermal reduction/oxidation (REDOX) cycle. The focus of the research is nickel ferrite (NixFe3-xO4) produced through atomic layer deposition (ALD) on zirconia and alumina substrates. The ALD process allows for precise control of the atomic ratio of Ni/Fe in this material, and also has the potential to provide tight control over the mass loadings of the active ferrite on high surface area substrates.The performance of various ferrite materials and alternative water splitting cycles will be evaluated for their potential to produce H2. Variables to be investigated include ferrite stoichiometry, substrate composition, substrate surface area, REDOX temperatures, rate of reduction heating, and water concentration for oxidation. Specific measurements include REDOX reaction rates and thermochemical cycling using thermogravimetric analysis (TGA) for both thermal reduction at up to 1500 C and steam oxidation at up to 1200 C; depth profiling via X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) to evaluate chemical and structural changes during REDOX cycling; and finally, atomic force microscopy (AFM) to evaluate the robustness of ferrite materials and to assess the possibility of "islanding" resulting from sintering. Experiments are planned to carry out the REDOX cycles under simulated solar-thermal conditions using a High Flux Solar Furnace equipped with a TGA for real-time measurement of heating and cooling rates. By all of these approaches, the importance of diffusion vs. kinetic rate limitations on the splitting of water to H2 by metal ferrite spinels can be assessed.The proposed research is potentially transformative because metal ferrite materials produced through the ALD process have unique a potential to provide high hydrogen gas production rates at the efficiencies needed to make solar-thermal hydrogen production technology viable. Broader ImpactThe education activities will make use of existing NSF (REU) and Department of Education programs (GAANN) to recruit and train undergraduate and graduate students in the proposed research, including students from under-represented groups. Outreach to K12 will also be organized through these programs using students involved in the proposed research.

0966201Weimerthere需要开发具有成本效益的可再生能源过程，以生产清洁燃料（例如氢气（H2））。 如果可以通过使用浓缩的阳光将水分裂有效地获得成本，那么可以使用可再生的H2操作燃料电池以发电或基于可再生的H2合成其他燃料。知识分子值得拟议的研究的总体目标是对金属铁氧体尖晶石通过太阳能还原/氧化（氧化还原）循环的能力进行基本了解。该研究的重点是通过氧化锆和氧化铝底物上的原子层沉积（ALD）产生的镍铁氧体（Nixfe3-XO4）。 ALD过程允许精确控制该材料中Ni/Fe的原子比，并且还具有对高表面积底物上活性铁氧体的质量负荷的严格控制。各种铁素体材料和替代水分裂解循环的性能将评估以产生H2的潜力。 要研究的变量包括铁氧体化学计量学，底物组成，底物表面积，氧化还原温度，还原速率以及氧化的水浓度。 特定的测量包括使用热重分析（TGA）的氧化还原反应速率和热化学循环，可在1500 C下进行热还原，以及最高1200 C的蒸汽氧化；通过X射线光电子光谱（XP）和X射线衍射（XRD）进行深度分析，以评估氧化还原循环期间的化学和结构变化；最后，原子力显微镜（AFM）评估铁氧体材料的鲁棒性，并评估烧结引起的“岛化”的可能性。 计划使用配备了TGA的高通量太阳能炉在模拟的太阳热条件下进行氧化还原周期，以实时测量加热和冷却速率。 通过所有这些方法，可以评估扩散率限制对通过金属铁氧体尖晶石将水分裂为H2的重要性。拟议的研究具有潜在的转化性，因为通过ALD过程产生的金属铁矿材料具有独特的潜力，可以使高氢气生产速率以使Solar-Thermal-Hyderogal生产效率降低。 更广泛的影响教育活动将利用现有的NSF（REU）和教育计划（GAANN）来招募和培训拟议研究的本科生和研究生，包括来自代表性不足的小组的学生。 还将使用参与拟议研究的学生通过这些计划来组织与K12的宣传。