凯文博士称，想法很简单，应用却很广泛。这一技术用光伏电池（洁净能源）驱动电化学反应（净化反应），凯文博士认为，这不是一个新学科，他只是把两个已存在技术结合在一起，希望能改变人们做化学实验的方式。
研究人员进行试验
为了突出想法的简单性，穆勒和作者网购6美元的太阳能电池，用它驱动玩具车从而进行化学实验，具体实验记录在Green Chemistry期刊的论文中。
如果化学工业广泛采用他们的建议，目前普遍使用的化学合成反应可产生较少的有毒副产物，以及环境和经济损失都会降低到最低限度。
化学反应的问题
华盛顿大学艺术与科学学院（Arts & Sciences at Washington University）穆勒教授是一个有机化学家，他主要靠碳，氢，氧和氮小分子合成的生物大分子。氧化反应是合成包括麻醉剂和药用纱布在内的许多有机分子一个途径，通过这一途径，我们可以进行更多的操作，进而提高生物大分子的功能。分子之间相互作用通过原子结合形成功能基团，一个分子功能基团越多，你越能控制分子间如何作用。
在氧化反应中，电子要从分子中脱离出来，它总要找个去处吧。因此，氧化反应和还原反应是成对出现的，在还原反应中还原剂是电子的受体分子，然而，问题是这一受体分子是无用的产物。
寻求更清洁的副产品
凯文博士说，所用的化学反应都有副产品，问题不是是否有副产品，而是副产品是什么。人们开始考虑氧化反应怎样进行的同时还应该考虑还原产物是什么。如果你用氧气去氧化，副产物是水，这是一个很温和的过程，但是，这一过程涉及到电子的捕获，氧气以氧化态的形式存在。
想法简单 化学反应却很清洁
还有其它方法去设计氧化还原。电化学反应可以氧化具有氧化性地分子， 由于电极电压可以调整，或者是化学反应按照一定方式自我调整，因此凯文博士就能灵活性设计试验。此外，电化学中氧化反应的副产物是氢气，因此，这也是一个清洁环保的过程。电化学可以像电能一样清洁环保，如果氧化反应是清洁的，而电能来自燃煤的供电厂，问题还是没法解决。解决途径之一是使用太阳能电池捕获的最清洁能源，为电化学反应提供能量。这就是Green Chemistry论文的主题。
下一步
Green Chemistry论文介绍了有关电极附近分子直接参与氧化反应的方法，不使用任何试剂。穆勒领导的团队一直在研究太阳能供能的电化学反应如何以一种清洁方式循环使用化学氧化剂。
如果电极电压能够支持必需氧化分子的氧化潜能，生产人员为什么还要使用化学氧化剂？
“为了让化学反应可选择化，化学界正在尝试怎样使用化学试剂，这些化学试剂往往很贵且有毒，我们做的就是让试剂循环使用更加清洁环保。”穆勒说。
他还说，通过太阳能为电化学反应供能的途径，我们不能使所有的化学合成都很清洁，但至少可以锁定人们使用的氧化反应，或许，它能激发其他人想到简单且有创意的解决途径。（生物探索译）
生物探索推荐英文全文
Chemistry With Sunlight: Combining Electrochemistry and Photovoltaics to Clean Up Oxidation Reactions
The idea is simple, says Kevin Moeller, PhD, and yet it has huge implications. All we are recommending is using photovoltaic cells (clean energy) to power electrochemical reactions (clean chemistry). Moeller is the first to admit this isn't new science.
"But we hope to change the way people do this kind of chemistry by making a connection for them between two existing technologies," he says.
To underscore the simplicity of the idea, Moeller and his co-authors used a $6 solar cell sold on the Internet and intended to power toy cars to run reactions described in an article published in Green Chemistry.
If their suggestion were widely adopted by the chemical industry, it would eliminate the toxic byproducts currently produced by a class of reactions commonly used in chemical synthesis -- and with them the environmental and economic damage they cause.
The trouble with oxidation reactions
Moeller, a professor of chemistry in Arts & Sciences at Washington University in St. Louis, is an organic chemist, who makes and manipulates molecules made mainly of carbon, hydrogen, oxygen and nitrogen.
One important tool for synthesizing organic molecules -- an enormous category that includes everything from anesthetics to yarn -- is the oxidation reaction.
"They are the one tool we have that allows us to increase the functionality of a molecule, to add more "handles" to it by which it can be manipulated," says Moeller.
"Molecules interact with each other through combinations of atoms known as functional groups," he explains. "Ketones, alcohols or amines are all functional groups. The more functional groups you have on a molecule, the more you can control how the molecule interacts with others."
"Oxidation reactions attach functional groups to a molecule," he continues. "If I have a hydrocarbon that consists of nothing but carbon and hydrogen atoms bonded together, and I want to convert it to an alcohol, a ketone or an amine, I have to oxidize it."
In an oxidation reaction, an electron is removed from a molecule. But that electron has to go somewhere, so every oxidation reaction is paired with a reduction reaction, where an electron is added to a second molecule.
The problem, says Moeller, is that "that second molecule is a waste product; it's not something you want."
One example, he says, is an industrial alcohol oxidation that uses the oxidant chromium to convert an alcohol into a ketone. In the process the chromium, originally chromium VI, picks up electrons and becomes chromium IV. Chromium IV is the waste product of the oxidation reaction.
In this case, there is a partial solution. Sodium periodate is used to recycle the highly toxic chromium IV. A salt, the sodium periodate dissociates in solution and the periodate ion (an iodine atom with attached oxygens) interacts with the chromium, restoring it to its original oxidation state.
The catch is that restoring the chromium destroys the periodate. In addition, the process is inefficient; three equivalents of periodate is consumed for every equivalent of desired product produced.
Seeking cleaner byproducts
"All chemical oxidations have a byproduct, says Moeller, so the question is not whether there will be a byproduct but what that byproduct will be. People have starting thinking about how they might run oxidations where the reduced byproduct is something benign."
"If you use oxygen to do the oxidation, the byproduct is water, and that is a gentle process," he says.
But there is a catch. Like all other molecules, oxygen has a set oxidation potential, or willingness to accept electrons. "So whatever I want to oxidize in solution has to have an oxidation potential that matches oxygen's. If it doesn't, I might have to change my whole reaction around to make sure I can use oxygen. And when I change the whole reaction around, maybe it doesn't run as well as it used to. So I'm limited in what I can do," Moeller says.
A simpler idea is also cleaner.
There's another way to do it. "Electrochemistry can oxidize molecules with any oxidation potential, because the electrode voltage can be tuned or adjusted, or I can run the reaction in such a way that it adjusts itself. So I have tremendous versatility for doing things," says Moeller.
Moreover, the byproduct of electrochemical oxidation is hydrogen gas, so this too is a clean process.
But again there is a catch. Electrochemistry can be only as green as the source of the electricity. If the oxidation reaction is running clean, but the electricity comes from a coal-fired plant, the problem has not been avoided, just displaced.
The answer is to use the cleanest possible energy, solar energy captured by photovoltaic cells, to run electrochemical reactions.
"That's what the Green Chemistry article is about," says Moeller. "It's a proof-of-principle paper that says it's easy to make this work, and it works just like reactions that don't use photovoltaics, so the chemical reaction doesn't have to be changed around."
The next step
The Green Chemistry article demonstrated the method by directly oxidizing molecules at the electrode. No chemical reagent was used. Since writing the article, Moeller's group has been studying how solar-powered electrochemistry might be used to recycle chemical oxidants in a clean way.
Why would manufacturers choose to use a chemical oxidant, if the voltage of the electrode can be matched to the oxidation potential of the molecule that must be oxidized?
"An electrode selects purely on oxidation potential," Moeller explains. "A chemical reagent does not. The binding properties of the chemical reagent might differ from one part of the molecule to another. And there's also something called steric hindrance, which means that one part of the molecule might physically block access to an oxidation site, forcing substrates to other sites on the reagent."
"The chemistry community has learned how to use chemical reagents to make reactions selective," he says. "The reagents are usually expensive and toxic, so they are recycled," he says. "We are working on cleaning up reagent recycling."
In the chromium oxidation described above, for example, chromium IV could be recycled electrochemically instead of through a reaction with periodate. Instead of periodate waste[consistent with description above where periodate consumed?], the reaction would produce hydrogen gas as the byproduct.
"Another example is an industrial process for carrying out alcohol oxidations that convert the alcohol group to a carbonyl group," says Moeller. This process uses TEMPO, a complex chemical reagent discovered in 1960. TEMPO is expensive so it is recycled by the addition of bleach. This regenerates the TEMPO but produces sodium chloride as a byproduct."
In small quantities sodium chloride is table salt, but in industrial quantities it is a waste product whose disposal is costly. Once again, the TEMPO can be recycled using electrochemistry, a process that produces hydrogen as the only byproduct.
"We can't make all of chemical synthesis cleaner by hitching solar power to electrochemistry," Moeller says, "but we can fix the oxidation reactions that people use. And maybe that will inspire someone else to come up with simple and innovative solutions to other types of reactions they're interested in."
