Photocatalysis with Ferroelectric Light Absorbers

用铁电吸光器进行光催化用清洁替代品取代污染严重的化石燃料是现代世界面临的重大挑战之一。更可持续的能源经济可能会通过光催化剂来实现，这种光催化剂可以利用阳光作为唯一的能源投入，从水中生产氢燃料。氢被认为是一种“绿色”燃料，因为它通过重新生成水来释放储存的能量。已知的光催化剂的一个问题是，它们的能量转换效率很低，也就是说，它们从阳光中吸收了大量能量，但只有一部分能量被转化为可用的燃料。本项目研究利用铁电吸光体来提高能量转换效率。采用显微、光学、电学和化学等方法对新型铁电吸光材料进行了研究。这项研究是由一名博士后助理和研究生进行的。所有小组成员都接受了材料准备和现代工具和技术的应用培训，以确定材料的特性。还为来自代表性不足群体的本科生创造了新的实习职位。当地学校和校园里的化学节目激励孩子们学习自然科学，解决清洁能源等重要的社会问题。实验演示以在线材料的形式分发，以教育公众关于可持续燃料的研究。在化学系化学催化计划的资助下，加州大学戴维斯分校的Osterloh博士正在研究一组来自钙钛矿M：ATiO3的光催化剂材料的铁电效应。这里，A是土碱性元素，M是过渡金属离子。这些材料与用于生产可持续能源的第三代光伏设备和光催化剂的开发有关。以丰富的元素为原料，采用固相法和水热法合成了化合物，并用电子显微镜、X射线衍射仪、X射线光电子能谱和紫外可见光谱对其进行了表征。采用水氧化还原共催化剂的择位修饰方法制备了可用于整个水分解反应的铁电光催化剂。使用介电极化实验、表面光电压谱、光催化和电化学测量相结合的方法来确定铁电偶极子可以在多大程度上增强这些材料的光化学能到燃料的转化。此外，该项目还培训研究生、研究生和本科生制备无机材料以及表征其形态、结构和光化学的先进方法。开展外展活动是为了吸引和激励下一代STEM学生从事催化研究。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Photocatalysis with Ferroelectric Light AbsorbersReplacing polluting fossil fuels with clean alternatives is one of the grand challenges of the modern world. A more sustainable energy economy may be achievable with photocatalysts that can produce hydrogen fuel from water, using sunlight as the only energy input. Hydrogen is regarded as a "green" fuel because it releases its stored energy by re-forming water. A problem of known photocatalysts is that their energy conversion efficiency is low, that is, they absorb a lot of energy from sunlight but only some of this energy is converted to a usable fuel. This project studies the use of "ferroelectric" light absorbers to increase the energy conversion efficiency. The new ferroelectric light absorbing materials are studied using microscopic, optical, electrical, and chemical methods. The research is conducted by a postdoctoral associate and by graduate students. All team members are trained in the preparation of the materials and in the application of modern instruments and techniques for their characterization. New internship positions for undergraduate students from underrepresented groups are also created. Chemistry shows at local schools and on campus motivate children to study the natural sciences, tackling important societal problems like clean energy. Experimental demonstrations are distributed as online materials to educate the public about sustainable fuel research.With funding from the Chemical Catalysis Program of the Chemistry Division, Dr. Osterloh of the University of California, Davis, is studying ferroelectric effects in a set of photocatalyst materials derived from the perovskites M:ATiO3. Here, A is an earth alkaline element and M is a transition metal ion. These materials are relevant to the development of third generation photovoltaic devices and photocatalysts for the production of sustainable energy. The compounds are synthesized with solid state and hydrothermal methods from abundant elements, and they are characterized with electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and UV/vis spectroscopy. Site-selective modification with water oxidation and reduction co-catalysts is applied to fabricate ferroelectric photocatalysts for the overall water splitting reaction. A combination of dielectric polarization experiments, surface photovoltage spectroscopy, photocatalytic, and electrochemical measurements is used to determine the extent to which ferroelectric dipoles can enhance photochemical energy to fuel conversion with these materials. Additionally, the project trains graduate, postgraduate and undergraduate students in the preparation of inorganic materials and advanced methods for characterizing their morphology, structure and photochemistry. Outreach events are conducted to engage and motivate the next generation of STEM students for research in catalysis. Online materials are disseminated to educate the public about sustainable energy production.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.