Solar Water Splitting: Photocatalyst Materials Discovery and Systems Development

McNulty, Thomas F.

关键词: ADSORPTION;    COMPRESSORS;    DISTRIBUTION;    DOLLARS;    ECONOMICS;    ELECTRICITY;    ELECTROLYSIS;    FOSSIL FUELS;    GASOLINE;    GREENHOUSE GASES;    HYDROGEN;    SOLAR RADIATION;    STORAGE;    TARGETS;    VIABILITY;    WATER Photoelectrochemical;    Hydrogen Production;   

DOI  :  10.2172/927771
RP-ID  :  DOE/GO/15024
PID  :  OSTI ID: 927771
Others  :  TRN: US200815%%257

学科分类：再生能源与代替技术

美国|英语

来源: SciTech Connect

【 摘 要 】

Hydrogen promises to be an attractive transportation fuel in the post-fossil fuel era. Relatively abundant and clean burning (water being the principal byproduct), hydrogen offers the potential to significantly reduce greenhouse gas emissions. However, there are significant technical barriers that require solutions before hydrogen can be implemented in large scale. These are: · Sources (e.g. hydrocarbon, water) · Transportation · Storage Each of the aforementioned barriers carries with it important considerations. First, would a hydrocarbon-based hydrogen source be of any benefit compared to conventional fossil fuels? Second, will a system based on centralized generation and distribution be viable? Finally, methods of on-board storage, whether they are liquefaction, adsorption, or intercalation, are far from optimized. The scope of this program is limited to hydrogen generation, specifically generation using solarinitiated water electrolysis. Though concept of making hydrogen using water and sunlight may sound somewhat far-fetched, in reality the concept is very real. Since the discovery of solar-generated hydrogen, termed photoelectrochemical hydrogen, nearly 30 years ago by Fujishima and Honda, significant advances in both fundamental understanding and technological capability have been made. Using solar radiation to generate hydrogen in a fashion akin to using solar to generate electricity offers many advantages. First, hydrogen can be generated at the point of use, reducing the importance of transportation. Second, using water as the hydrogen source eliminates greenhouse gas evolution and the consequences that come with it. Finally, because the process uses very little electricity (pumps and compressors predominantly), the quantity of chemical fuel produced far exceeds the amount of electricity consumed. Consequently, there is some level of truth to the notion that photoelectrochemically-derived hydrogen offers the potential to nearly eliminate greenhouse gas emissions from the transportation landscape. This report focuses primarily on the technical issues inherent to developing an economically viable photoelectrochemical hydrogen system. This involves research intended to address technology gaps as well as research to address commercial feasibility. Though a firm cost target is not identified explicitly, much of the economics are presented in terms of “dollars per gallon of gasoline equivalent” ($/gge). Obviously this is a moving target, but it is important to understand cost in terms of current gasoline pricing, since the intended target is gasoline replacement. However, this does put the cost contribution into a perspective that at least allows for a reasonable assessment of technological viability. It also allows for the identification of need areas beyond the obvious technology gaps.