Modular Construction of Nanostructured Catalysts for Solar Hydrogen Generation from Water

CBET-0829142 Osterloh照射地球超过一小时的阳光提供的能量足以满足人类一整年的能量需求。 然而，将这种能量转化为可用燃料的有效方法还没有找到，在这方面特别感兴趣的是利用光将水光化学分解为氧气和氢气的材料。 氢则作为一种环境友好的能量载体。 已知许多无机材料催化这种“水裂解反应”，但它们的效率对于商业应用来说仍然太低。 该项目的目的有两个。 首先，将开发一类新的水分解催化剂，其可以以模块化的方式从无机纳米颗粒组装。 在这里，纳米颗粒作为光吸收和水转化的单独组分起作用。 这种构建块方法的优点是，光吸收，电荷转移和化学性质可以独立优化。 最终的催化剂是粉末，可以在水中混合，从丰富的太阳能中产生清洁的氢气。 该项目的第二个目标是了解更多关于纳米颗粒催化剂光化学分解水的机理。 这里的第一步将是测量在紫外线或可见光照射下释放的氢和氧的量，并将气体产生与催化剂的结构相关联。 其次，将采用时间分辨吸收光谱法来确定光转化为电荷的有效性以及电荷移动到催化剂表面的速度，在催化剂表面发生水转化。 纳米颗粒表面分解水的有效性将使用电化学方法单独研究。 类似的方法也将用于确定纳米颗粒组分的电子结构，其控制催化剂内的电荷流动。 这些研究结果将有助于加深对无机纳米结构催化活性的理解，并有助于提高其效率。该项目的研究部分将伴随着一些教育和推广活动，包括一个新的研究生班“纳米粒子化学”和科学展览和公众化学展。 研究生和本科生的研究也将创造新的机会。 这些活动旨在招募和教育新一代科学家和工程师，他们可以帮助开发更有效的方法来利用阳光作为可再生能源。

CBET-0829142OsterlohThe sunlight that strikes the earth over one hour provides enough energy to satisfy all human energy needs for an entire year. However, efficient methods of conversion of this energy into usable fuels have yet to be found. Of particular interest in this regard are materials that use light to photochemically split water into oxygen and hydrogen. The hydrogen then serves as an environmentally friendly energy carrier. Many inorganic materials are known to catalyze this "water splitting reaction", but their efficiency remains too low for commercial applications. The purpose of this project is twofold. First, a new class of water splitting catalysts will be developed that can be assembled in a modular fashion from inorganic nanoparticles. Here, the nanoparticles function as separate components for light absorption and water conversion. The advantage of this building block approach is that light absorption, charge transfer, and chemical properties can be independently optimized. The final catalysts are powders that can be mixed in water to produce clean hydrogen from abundant solar energy. The second goal of the project is to learn more about the mechanism of photochemical water splitting with nanoparticle catalysts. A first step here will be to measure the amount of evolved hydrogen and oxygen under ultraviolet or visible light illumination, and to correlate gas production with the structure of the catalysts. Secondly, time-resolved absorption spectroscopy will be employed to determine how effectively light is converted into charge and how quickly the charge travels to the surface of the catalysts, where water conversion takes place. The effectiveness of the nanoparticle surfaces to split water will be studied separately using electrochemical methods. Similar methods will also be used to determine the electronic structure of the nanoparticle components, which control the flow of charge within the catalysts. The results from these studies will improve the understanding of the catalytic activity of inorganic nanostructures, and help to raise their efficiency. The research portion of this project will be accompanied with several educational and outreach activities, including a new graduate class "Chemistry of Nanoparticles" and science exhibits and chemistry shows for the public. New opportunities for graduate and undergraduate student research will also be created. These activities are designed to recruit and educate a new generation of scientists and engineers who can help to develop more effective ways to utilize sunlight as a renewable energy source.