Nanocrystal Tandems as Improved Solar Water Splitting Photocatalysts

PI: OsterlohProposal Number: 1133099Intellectual Merit太阳能？以氢气（H2）的形式生产清洁、无碳的可再生燃料是一条很有前途的途径。虽然许多半导体材料催化这种反应，但太阳能转换效率仍然太低（1%），无法用于商业应用。本研究的总体目标是合成纳米晶串联光催化剂用于太阳能驱动的水分解。这些催化剂结合了串联电池的高理论效率极限（24%）和无机纳米晶体的优点，包括高结晶度、短电荷传输途径和可调节的电子结构。悬浮在水中或像薄膜一样沉积，串联光催化剂将被设计为实现以大于1%的效率分解水的困难技术目标。拟议的研究有两个基本目标。第一个目标是合成定义良好的纳米晶体模型系统，以便在串联光催化剂系统中详细研究光吸收、光化学电荷产生和电荷转移。这些性质是无机纳米晶体在太阳能转换和光催化方面应用的核心。第二个目标是获得对金属氧化物和硫族化物纳米晶体的光化学和电荷转移性质的基本认识，并将这些性质与它们的电子结构联系起来。在这里获得的机理见解将作为设计新的水分解光催化剂的基础。更广泛的影响拟议的活动旨在教育学生和公众有关太阳能和气候变化的问题，并从拟议的研究中获得实例。为此，无机纳米粒子的光催化特性模块将被纳入加州大学戴维斯分校（UC-Davis）化学系催化研究生课程，用于光催化制氢的金属氧化物凝胶的合成和测试实验模块将被纳入加州大学戴维斯分校的本科化学实验室。光催化H2演示也将被开发并纳入将通过加州大学戴维斯分校化学俱乐部进行的公众化学表演中。

PI: OsterlohProposal Number: 1133099Intellectual Merit The solar energy?]driven splitting of water into hydrogen and oxygen is promising route for the production of clean, carbon-free renewable fuel in the form of hydrogen gas (H2). Although many semiconductor materials catalyze this reaction, the solar energy conversion efficiency is still too low (1%) for commercial applications. The overall goal of this proposed research is to synthesize nanocrystal tandem photocatalysts for solar energy driven water splitting. These catalysts combine the high theoretical efficiency limit of tandem cells (24%) with the advantages of inorganic nanocrystals, including high crystallinity, short charge transport pathways, and adjustable electronic structure. Suspended in water or as deposited as a thin film, the tandem photocatalysts will be designed to achieve the difficult technical goal of splitting water at greater than 1% efficiency.The proposed research has two fundamental objectives. The first objective is to synthesize well-defined nanocrystal model systems that will allow detailed studies on light absorption, photochemical charge generation and charge transfer in tandem photocatalyst systems. These properties are central to applications of inorganic nanocrystals for solar energy conversion and photocatalysis. The second objective is to gain fundamental understanding on the photochemical and charge transfer properties of metal oxide and chalcogenide nanocrystals, and relate these properties to their electronic structure. The mechanistic insight gained here will serve as the basis for designing new water splitting photocatalysts.Broader ImpactsThe proposed activities are designed to educate students and the public on issues related to solar energy and climate change, with examples derived from the proposed research. Towards this end, a module on the photocatalytic properties of inorganic nanoparticles will be incorporated into a graduate level class on catalysis in the Chemistry Department at the University of California at Davis (UC-Davis), and an experimental module on synthesis and testing of metal oxide gels for photocatalytic H2 production will be incorporated into the undergraduate chemistry laboratory at UC-Davis. A photocatalytic H2 demo will also be developed and incorporated into chemistry shows for the public that will be performed through the UC-Davis Chemistry Club.