Advanced Bio-Photovoltaic Devices for Solar Energy Conversion

大气中二氧化碳含量的上升，以及对能源安全的担忧，意味着人们对开发可再生能源技术的兴趣越来越大。太阳能技术被认为特别有吸引力，因为每年有超过10万太瓦的太阳能落在地球上。目前，人类每年使用10太瓦的能源，到2050年，预计我们的能源需求将翻一番，达到每年20太瓦。因此，从理论上讲，太阳能技术可以提供我们未来能源需求的很大一部分是可行的。然而，以一种廉价、高效的方式收集大部分太阳能，带来了许多困难的技术挑战。目前，硅基太阳能光伏电池是首选的方法，但这些设备的制造成本往往非常昂贵，因为它们含有高度纯化的半导电材料。在这个应用中，我们建议利用与光合作用相关的光化学反应，这是一个基本的生物过程，通过生物光伏板将阳光转化为可用的能量形式。利用基于植物科学、生物化学、遗传学、工程和化学的多学科联盟，我们打算开发、测试和优化用于生产氢气和/或电力的生物光伏。在生物制氢领域已经进行了大量的工作，但到目前为止，事实证明很难克服限制该技术商业化的主要技术障碍，即光合作用过程中产生的氧气会抑制体内氢化酶产生氢气。虽然有一些人对用纯化蛋白复合物制造人工装置来克服这个问题感兴趣，但这些蛋白质的不稳定性阻碍了经济开发。在这项应用中，我们建议在使用完整光合细胞的半生物光伏装置中分离析氧和产氢过程，其中蛋白质复合物本质上更稳定，并且具有自我修复机制。该装置将由两个腔室或半电池组成，其中一个腔室限制氧气释放，另一个腔室限制氢气产生。此外，该方法可用于以类似于标准硅基光伏板的方式产生直流电流。

Rising atmospheric carbon dioxide levels, and concerns over energy security, mean that there is increasing interest in developing renewable energy technologies. Solar technologies are deemed to be particularly attractive, since over 100 000 TW of solar energy falls on the Earth every year. The human population currently use 10 TW of energy per annum, and by 2050, it is predicted that our energy demand will double to 20 TW per annum. It is therefore theoretically feasible that solar technologies could provide a significant proportion of our future energy requirement. However, harvesting a large proportion of this solar energy, in a cheap, efficient manner, poses many difficult technical challenges. At present, silicon based solar PV cells are the method of choice, but these devices tend to be very expensive to manufacture, since they contain highly purified, semi-conductive materials. In this application we propose to harness the photochemical reactions associated with photosynthesis, a fundamental biological process, to convert sunlight into a usable form of energy by means of a biological photovoltaic panel. Using a multidisciplinary consortium of groups based in Plant Science, Biochemistry, Genetics, Engineering and Chemistry we intend to develop, test and optimise biological photovoltaics for the production of hydrogen and/or electricity. A large amount of work has already been carried out in the field of biological hydrogen production, but so far it has proved difficult to overcome the major technical hurdle that limits the commercialisation of this technology, namely that the oxygen produced during photosynthesis inhibits the production of hydrogen from the hydrogenase enzyme in vivo. Although there has been some interest in fabricating artificial devices with purified protein complexes to overcome this problem, the instability of these proteins has prevented economic exploitation. In this application, we propose to separate the processes of oxygen evolution and hydrogen production in a semi-biological photovoltaic device using intact photosynthetic cells, in which protein complexes are intrinsically more stable, and which furthermore have mechanisms for self-repair. The device will be composed of two chambers, or half-cells, with oxygen evolution confined to one chamber and hydrogen production to the other. In addition, the approach can be used to produce a DC electrical current, in a manner analogous to standard silicon based photovoltaic panels.