NSF/DOE Solar Hydrogen Fuel: Engineering Surfaces, Interfaces, and Bulk Materials for Unassisted Solar Photoelectrochemical (PEC) Water Splitting

开发可再生能源替代化石燃料以满足全球能源和化学需求的紧迫性日益增加。氢气是一种很有前途的可再生燃料，可以由可持续资源制成。一种特别有前途的生产可再生氢气的途径是光电化学（PEC）水分解，其中太阳能的光子在催化剂材料的存在下被用来将水转化为氢气和氧气。这项提议的研究工作旨在解决该领域的基础研究挑战，促进活性，稳定和易于获得的材料的发展，这些材料可以吸收太阳的光子，并利用这些光子驱动水在材料表面分裂成氢气。为了实现这一目标，拟议的研究工作将改变地壳中丰富的金属氧化物化合物和元素混合物的表面化学性质，以使电子特性能够改善光吸收和催化水分解。继续研究将提高这些材料在水中的稳定性。研究生和本科生将是该项目的主要研究人员，培养他们成长为可再生能源技术领域未来领导者所需的技能。项目活动还包括对拉丁裔社区的大力推广，包括波多黎各的K-12和本科生，以及加州帕洛阿尔托社区的拉丁裔学生和家长。技术说明氢气是一种很有前途的可再生燃料，可由可持续资源制成。该项目将对无辅助光电化学（PEC）将水分解为氢气的表面、界面和大块材料进行综合研究。计算模型表明，由硅光电阴极和钒酸铋光电阳极组成的串联电池可达到10%的太阳能制氢效率，相当于每平方米太阳能收集表面的化学能为100 J/s。该项目的目标是获得对设计材料的基本理解，该材料可在酸中稳定且仅由地球丰富的元素组成的串联电池中实现10%的STH。为了实现这一目标，硅光电阴极以及高性能III-V半导体光电阳极将通过用硫化钼纳米材料修饰表面来改善其在酸中的活性和稳定性。类似地，钒酸铋光阳极将用于改进电子性能、耐久性和酸催化。研究的结果将提供对PEC材料失效机制的基本理解。硅和钒酸铋串联电池将在实验室受控条件下和使用美国能源部国家可再生能源实验室设备在真实太阳能条件下的室外测试设施中制造和测试氢气和氧气。总的来说，这种方法有可能促进基本的理解，同时也创造了新的技术，有可能通过PEC水分解高效和稳定的制氢。在教育和扩大参与方面，研究生和本科生将是这个项目的主要研究人员，为他们培养必要的技能，使他们成长为未来可再生能源技术领域的领导者。项目活动还包括对拉丁裔社区的大力推广，包括波多黎各的K-12和本科生，以及加州帕洛阿尔托社区的拉丁裔学生和家长。

Principal Investigator: Thomas F. JaramilloNumber: 1433442 Nontechnical DescriptionThere is growing urgency to develop renewable alternatives to fossil fuels for satisfying global energy and chemical demands. Hydrogen gas is a promising renewable fuel that can be made from sustainable resources. One particularly promising route to produce renewable hydrogen gas is photoelectrochemical (PEC) water splitting, in which the photons of solar energy are used to convert water into hydrogen and oxygen gas in the presence of a catalyst material. This proposed research effort is aimed at tackling fundamental research challenges in this field, facilitating the development of active, stable, and readily available materials that can absorb the sun's photons and use these photons to drive the splitting of water into hydrogen gas on the surface of the material. Towards this end, the proposed research effort will modify the surface chemistry of mixtures of metal oxide compounds and elements abundant in the earth's crust to enable the electronic properties that improve light absorption and catalyse water splitting. Continued studies will improve the stability of these materials in water. Graduate students and undergraduate students will be the primary researchers on this project, building the skills necessary for them to grow into future leaders in the renewable energy technology sector. The project activities also feature significant outreach efforts to the Latino community, including K-12 and undergraduate students in Puerto Rico, as well as Latino students and parents in the Palo Alto, California community. Technical DescriptionHydrogen gas is a promising renewable fuel which can be made from sustainable resources. This project will perform an integrated study of the surfaces, interfaces, and bulk materials for unassisted photoelectrochemical (PEC) splitting of water to hydrogen gas. Computational modeling suggests that a tandem cell consisting of a Si photocathode and a bismuth vanadate photoanode can reach solar-to-hydrogen (STH) efficiencies of 10%, corresponding to100 J/s of chemical energy per square meter of solar energy collection surface. The goal of this project is to gain a fundamental understanding of materials designed to achieve 10% STH in a tandem cell that is stable in acid and consists of only earth-abundant elements. To achieve this goal, Si photocathodes as well as high-performance III-V semiconductor photoanodes will be engineered for improved activity and stability in acid by modifying the surface with molybdenum sulfide nano-materials. Similarly, bismuth vanadate photoanodes will be engineered for improved electronic properties, durability, and catalysis in acids. Outcomes from studies will provide a fundamental understanding of the failure mechanisms in PEC materials. Tandem cells of Si and bismuth vanadate will be fabricated and tested for hydrogen and oxygen gas production in both the laboratory under controlled conditions and at outdoor testing facilities under true solar conditions using US Department of Energy National Renewable Energy Laboratory facilities. Overall, this approach has the potential to advance fundamental understanding while also creating new technologies with the potential for efficient and stable hydrogen production by PEC water-splitting. With respect to education and broadening participation, graduate students and undergraduate students will be the primary researchers on this project, building the skills necessary for them to grow into future leaders in the renewable energy technology sector. The project activities also feature significant outreach efforts to the Latino community, including K-12 and undergraduate students in Puerto Rico, as well as Latino students and parents in the Palo Alto, California community.