Nanocrystalline Water Splitting Photodiodes II: Device Engineering, Integration and Scale-up

摘要化石燃料是大多数工业化国家的主要能源，全球库存正在迅速枯竭，促使人们对替代能源的兴趣日益浓厚。近年来，随着越来越多的政治和社会接受的观察，燃烧化石燃料发电是全球变暖的主要贡献者，每年释放到大气中，这种浓厚的兴趣大大增强。8.0十亿吨二氧化碳，即二氧化碳。目前大气中的10%。在可替代化石燃料的可再生能源中，只有阳光或太阳能有能力满足当前全球的能源需求。事实上，落在地球上的太阳能超过人类目前的能源需求5000倍以上。不幸的是，它不是一种可以随时利用的形式，而是需要转化为电力或作为化学燃料储存。使用光伏器件（例如硅太阳能电池）或使用染料敏化太阳能电池将太阳能转化为电能是公认的。然而，电能不容易大量储存，太阳能是昼夜和间歇性的，当我们最需要它的时候，即在冬天的晚上，它最少。因此，真实的需要一种产生容易利用的化学燃料的高效（> 10%）、廉价（< £5/m2）的太阳能转换装置。直接太阳能驱动的水分解系统的优点是，它将太阳能转化为化学形式，即氢，其可以以最小的能量成本容易地储存或运输，并在需要时使用，并且在用作燃料时无污染，因为产品是水。在该项目的第一阶段，研究人员能够研究基本特性并开发小型实验室原型水裂解二极管。特别是，它表明，仔细设计的光催化剂-金属载体界面是高活性的关键，因为需要获得尽可能高的表面积，孔隙率和组成的光催化剂层。需要进一步改进光催化剂膜粘附性、可行的放大生产方法，以产生在真实的生活条件下高效和有效运行的实用原型。该装置还需要与某种燃料电池集成，以便作为能源解决方案广泛使用。因此，本拟定项目（第2阶段）终点的目标是制作一份高效、按比例放大的提案原始形式文件第3页，共10页打印日期：2010年10月12日10：48：54 TS/I 002855/1保存日期：2010年10月12日10：39：12能够收集太阳能的商业演示器，以（i）在家庭规模或接近家庭规模上将水分解成氢气和氧气工艺流，（ii）具有最终的、廉价的优化设计，这在生命周期分析和综合材料选择方面是可持续的，以及（iii）在设备集成到家庭利用模型方面获得重要和足够的专业知识;最值得注意的是通过商业燃料电池或燃烧器解决氢存储和后续使用的问题。第二阶段的终点将提供一个可行的设备，使用优化的催化剂和光催化剂以及最合适的涂层方法，在（i）高活性和鲁棒性和可扩展性（ii）经济影响;和（iii）环境，道德和社会考虑方面。

Summary Fossil fuels are the primary source of energy for most industrialised countries and global stocks are being rapidly depleted, prompting a growing interest in alternative energy sources. In recent years this keen interest has sharpened considerably with the increasingly politically and socially accepted observation that burning fossil fuels to create electricity is a, if not the, major contributor to global warming, releasing into the atmosphere every year ca. 8.0 Gig tonnes of carbon dioxide, CO2, i.e. ca. 10% of present atmospheric levels. Of the renewable energy resources that might substitute for the fossil fuels, only sunlight, or solar energy, has the capability to satisfy current global energy demands. Indeed, the amount of solar energy falling on the Earth is exceeding humankind's present energy requirements by > 5000 times. Unfortunately it is not in a form that can be always readily utilised but, instead, needs to be converted into electricity or stored as a chemical fuel. The conversion of solar to electrical energy using photovoltaic devices, such as the silicon solar cell or using dye-sensitised solar cells, is well-established. However, electrical energy is not easily stored in large amounts and solar energy is diurnal and intermittent and there is least of it when we most need it, i.e. at night in winter. As a consequence, there is a real need for an efficient (> 10%), inexpensive (< £5 per m2) solar energy conversion device that generates a readily utilised chemical fuel. The advantage of a direct solar-driven, water-splitting system is that it converts the sun's energy into a chemical form, i.e. hydrogen, that can be readily stored or transported at minimal energy cost and used when needed and is non-polluting when used as a fuel, since the product is water. In stage 1 of this project, the researchers were able to investigate the fundamental properties and develop small laboratory prototype water splitting diodes. In particular, it was shown that careful engineering of the semiconductor-metal support interface was critical to high activity, as was the need to obtain a high as possible surface area, porosity and composition of the photocatalyst layer. Further improvements with regard to photocatalyst film adhesion, viable scale-up production methods are required to create practical prototypes which would run efficiently and effectively under real life conditions. This device will also require integration with a fuel cell of some kind in order to be of broad use as an energy solution. Therefore, the target at the end-point of this proposed project (Stage 2) is the fabrication of an efficient, scaled up, Proposal original proforma documentPage 3 of 10 Date printed: 12/10/2010 10:48:54TS/I002855/1 Date saved: 12/10/2010 10:39:12commercial demonstrator capable of harvesting solar energy to (i) split water into hydrogen and oxygen process streams on or near to domestic scale, (ii) have a final, inexpensive optimised design, which is sustainable in terms of life cycle analysis and comprehensive materials selection and (iii) gain significant and sufficient know how in terms of device integration into domestic utilisation model; most notably addressing the issues of hydrogen storage and subsequent usage via a commercial fuel cell or burner. The end point of Stage 2 will deliver a viable device, using optimised catalyst(s) and photocatalysts and the most suitable coating method in terms of (i) high activity and robustness and scalability (ii) economic impact; and (iii) environmental, ethical and societal considerations.