蛋白质薄膜在潮湿的空气中产生无碳电流
Most of the world's electricity still comes from burning 100-million-year-old dead life-forms, but new alternatives keep appearing. The latest uses protein nanowires to draw electricity from the atmosphere, although since moisture from humidity is required, the air the power comes from isn't entirely thin.
世界上大部分的电力仍然来自于燃烧一亿年前死去的生命，但是新的替代能源不断出现。最新的技术是利用蛋白质纳米线从大气中获取电力，不过由于需要从湿度中获取水分，因此产生电力的空气并不完全稀薄。
The new device, named the Air-gen, is the brainchild of microbiologist Dr Derek Lovley and electrical engineer Dr Jun Yao, both from the University of Massachusetts, Amherst. They claim their creation avoids the key outstanding problem of other sorts of renewable energy. "The Air-gen generates clean energy 24/7," Yao said in a statement.
这种名为“空气发生器”的新设备是来自马萨诸塞大学阿姆赫斯特分校的微生物学家德里克·洛夫利博士和电气工程师姚俊博士的创意。他们声称他们的发明避免了其他可再生能源的关键问题。姚在一份声明中说:“空气能全天候产生清洁能源。”
Stephen Luntz
Some attempts to produce electricity from novel sources rely on exceptionally expensive raw materials. The film of electrically conductive nanowires connecting the Air-gen's two electrodes, however, is produced by Geobacter bacteria fed on a cheap diet. Gold leaf electrodes were used, but substitution with inert carbon also worked. The film is less than a hundredth of a millimeter thick and only partially covered by the top electrode, exposing it to the air. Pores in the film absorb atmospheric water vapor and a moisture gradient induces ionization, with positive charges diffusing one way and electrons the other.
有些利用新能源发电的尝试依赖于异常昂贵的原材料。然而，连接Air-gen的两个电极的导电纳米线薄膜是由吃廉价食物的Geobacter细菌制造的。使用金箔电极，但也可以用惰性碳代替。该薄膜的厚度不足百分之一毫米，并且只有部分被顶部电极覆盖，暴露在空气中。薄膜中的孔隙吸收大气中的水蒸气，水分梯度诱导电离，正电荷以一种方式扩散，电子则以另一种方式扩散。
On a laboratory scale, the Air-gen's energy density is high compared to most novel renewable energy devices. The test model Yao and Lovley describe in Nature produced 4mWatts/cm2 at best – about a fifth of a solar panel in full sunlight. That's almost as high as another recent renewable novelty, a panel that turns the kinetic energy of raindrops into electricity. However, existing modules are tiny – a quarter of a square centimeter, and scaling up may be a challenge.
在实验室规模，空气发电的能量密度比大多数新型可再生能源设备高。Yao和Lovley在《自然》杂志上描述的试验模型最多只能产生4mw /cm2的能量——大约是全日照下太阳能电池板的五分之一。这几乎和另一种最新的可再生能源一样高，一种将雨滴的动能转化为电能的面板。然而，现有的模块非常小——只有四分之一平方厘米，扩展可能是一个挑战。
On the other hand, Air-gen's capacity is uniquely resilient to changing weather conditions. Production dropped when humidity was outside an ideal range, but even Saharan conditions didn't stop it entirely. Electricity has been generated from humidity before, but with much lower power densities and only in bursts that last less than a minute. Air-gen appears able to keep going indefinitely, although even under constant humidity electricity production fell slowly over a day.
另一方面，Air-gen的能力对不断变化的天气条件具有独特的弹性。当湿度超出理想范围时，产量就会下降，但即便是撒哈拉地区的情况也未能完全阻止这一趋势。以前也曾利用湿度发电，但功率密度要低得多，而且只能在持续不到一分钟的突发情况下发电。空气发电似乎能够无限期地持续下去，尽管即使在恒湿的情况下，发电量也在一天内缓慢下降。
Initially, the authors hope to produce patches that power wearable electronic devices, and then paint the walls of off-grid houses with the nanowires. “Once we get to an industrial scale for wire production, I fully expect that we can make large systems that will make a major contribution to sustainable energy production,” Yao said.
一开始，作者们希望能制造出一种可以为可穿戴电子设备供电的贴片，然后用纳米线在离网房屋的墙壁上进行喷涂。姚说:“一旦我们达到工业规模的电线生产，我完全期待我们能够制造出大型系统，为可持续能源生产做出重大贡献。”
Lovley identified the Geobacter in Potomac River mud 30 years ago, and later discovered it eats electrons off rocks and produces electrically conductive protein nanowires. The idea of using these wires for electricity production came about by accident when Yao's PhD student Xiaomeng Liu was trying to use them to make sensors and noticed under certain circumstances current was produced.
洛夫利30年前在波托马克河的泥土中发现了Geobacter，后来发现它会吃掉岩石上的电子，并产生可导电的蛋白质纳米线。使用这些电线发电的想法是偶然产生的，当时姚的博士生刘晓萌正试图用它们来制作传感器，并注意到在一定的情况下会产生电流。
