将二氧化碳转化为工业燃料

One day in the not-too-distant future, thegases coming from power plants and heavy industry, rather than spewing into theatmosphere, could be captured and chemically transformed from greenhouse gaseslike carbon dioxide into industrial fuels or chemicals thanks to a new systemthat can use renewable electricity to reduce carbon dioxide into carbonmonoxide -- a key commodity used in a number of industrial processes.

在不久的将来的某一天，来自发电厂和重工业的气体将不再被喷入大气，它们能被捕获，并通过二氧化碳等温室气体转化为工业燃料或化学品，这些药归功于一种可以利用可再生电力的系统，该系统可以减少二氧化碳将其转换为一氧化碳——是用于许多工业过程中的关键商品。

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"To explore more possibilities, my group has alsodeveloped several copper-based catalysts that can further reduce CO2 intoproducts that are much more valuable," said Haotian Wang.

“为了探索更多的可能性，我的团队还开发了几种铜基催化剂，可以进一步将二氧化碳转化为更有价值的产品，”Wang Haotian说。

A Fellow at the Rowland Institute at Harvard, Wang andcolleagues have developed an improved system to use renewable electricity toreduce carbon dioxide into carbon monoxide -- a key commodity used in a numberof industrial processes. The system is described in a November 8 paperpublished in Joule, a newly launched sister journal of Cell press.

作为哈佛大学Rowland研究所的研究员，Wang及其同事开发了一种改进的系统，使用可再生电力将二氧化碳减少变为一氧化碳——这是许多工业过程中使用的关键商品。该系统在11月8日发表于Joule的论 中有所描述，Joule是一家新推出的Cell press姐妹期刊。

"The most promising idea may be to connect thesedevices with coal-fired power plants or other industry that produces a lot ofCO2," Wangsaid. "About 20 percent of those gases are CO2, so if you can pump them into this cell...and combine itwith clean electricity, then we can potentially produce useful chemicals out ofthese wastes in a sustainable way, and even close part of that CO2 cycle."

“最可行的办法可能是将这些设备与燃煤发电厂或其他产生大量二氧化碳的行业联系起来，”Wang说。 “这些气体中约有20％是二氧化碳，如果将它们泵入这中电池并将其与清洁电力结合起来，那么就可以可持续的方式从这些废物中产生有用的化学物质，甚至可以接近二氧化碳循环。“

The new system, Wang said, represents a dramatic stepforward from the one he and colleagues first described in a 2017 paper in Chem.

Wang说，新系统代表着他和同事们的重大进展，在2017年Chem的论 中首次描述过。

Where that old system was barely the size of a cell phoneand relied on two electrolyte-filled chambers, each of which held an electrode,the new system is cheaper and relies on high concentrations of CO2 gasand water vapor to operate more efficiently -- just one 10-by-10-centimetercell, Wang said, can produce as much as four liters of CO per hour.

那个旧系统的尺寸不到一个手机大小，依靠两个充满电解质的腔室，每个腔室都装有电极。新系统更便宜，依靠高浓度的二氧化碳气体和水蒸气来更有效地运行，Wang说，只需一个10×10厘米的电池，每小时可以产生多达4升的一氧化碳。

The new system, Wang said, addresses the two mainchallenges -- cost and scalability -- that were seen as limiting the initialapproach.

王说，新系统解决了两个主要挑战——成本和可扩展性，这也是被视为对最初方法的限制。

"In that earlier work, we had discovered the singlenickel-atom catalysts which are very selective for reducing CO2 to CO...butone of the challenges we faced was that the materials were expensive tosynthesize," Wang said. "The support we were using to anchor singlenickel atoms was based on graphene, which made it very difficult to scale up ifyou wanted to produce it at gram or even kilogram scale for practical use inthe future."

“在早期的工作中，我们发现了单一的镍原子催化剂，它们对于将二氧化碳减少变到一氧化碳非常有选择性......但我们面临的挑战之一就是材料的合成成本很高，”王说。 “我们用来锚定单个镍原子的支持是基于石墨烯的，如果你想在未来的实际应用中以克或甚至千克的规模生产它，就很难扩大规模。”

To address that problem, he said, his team turned to a commercialproduct that's thousands of times cheaper than graphene as an alternativesupport -- carbon black.

他说，为了解决这个问题，他的团队转向使用比石墨烯便宜数千倍的商业产品作为替代支持 - 炭黑。

Using a process similar to electrostatic attraction, Wangand colleagues are able to absorb single nickel atoms (positively charged) intodefects (negatively charged) in carbon black nanoparticles, with the resultingmaterial being both low-cost and highly selective for CO2 reduction.

使用类似于静电吸引的工艺，Wang及其同事能够将单个镍原子（带正电荷）吸收到炭黑纳米粒子中的缺陷（带负电）中，所得到的材料既低成本又对CO2减少具有高选择性。

"Right now, the best we can produce is grams, butpreviously we could only produce milligrams per batch," Wang said."But this isonly limited by the synthesis equipment we have; if you had alarger tank, you could make kilograms or even tons of this catalyst."

“现在，我们生产的最好的产品是克，但以前我们每批只能生产毫克，”王说。 “但这仅限于我们拥有的合成设备;如果你有一个更大的坦克，你可以制造千克甚至吨的这种催化剂。”

The otherchallenge Wang and colleagues had to overcome was tied to the fact that theoriginal system only worked in a liquid solution.

王和他的同事必须克服的另一个挑战是于原始系统只能在液体中工作有关。

The initial system worked byusing an electrode in one chamber to split water molecules into oxygen andprotons. As the oxygen bubbled away, protons conducted through the liquidsolution would move into the second chamber, where -- with the help of thenickel catalyst -- they would bind with CO2 and break the molecule apart,leaving CO and water. That water could then be fed back into the first chamber,where it would again be split, and the process would start again.

初始系统通过在一个腔室中使用电极将水分子分解成氧和质子来工作。当氧气冒出时，通过液体溶液传导的质子将进入第二个腔室，在镍催化剂的帮助下，它们将与二氧化碳结合并将分子分开，留下CO和水。然后可以将水反馈回第一个腔室，在那里它将再次被分开，并且该过程将再次开始。

"The problem was that, theCO2 we can reduce in that system areonly those dissolved in water; most of the molecules surrounding the catalystwere water," he said. "There was only a trace amount of CO2, so it was pretty inefficient."

“问题在于，我们在该系统中可以减少的二氧化碳只是那些溶解在水中的二氧化碳;催化剂周围的大多数分子都是水，”他说。 “只有微量的二氧化碳，因此非常低效。”

While it may be tempting to simply increase the voltageapplied on the catalyst to increase the reaction rate, that can have theunintended consequence of splitting water, not reducing CO2, Wang said.

Wang说，虽然简单地增加施加在催化剂上的电压以提高诱人的反应速率，但这会产生分裂水的意外后果，而不是减少CO2。

"If you deplete the CO2 that's close to theelectrode, other molecules have to diffuse to the electrode, and that takestime," Wang said. "But if you're increasing the voltage, it's morelikely that the surrounding water will take that opportunity to react and splitinto hydrogen and oxygen."

“如果消耗靠近电极的二氧化碳，其他分子必须扩散到电极，这需要时间，”王说。 “但如果你增加电压，周围的水更有可能利用这个机会反应并分裂成氢气和氧气。”

The solution proved to be relatively simple -- to avoidsplitting water, the team took the catalyst out of solution.

事实证明，解决方案相对简单——为了避免分解水，团队将催化剂从液体中解脱出来。

"We replaced that liquid water with water vapor, andfeed in high-concentration CO2 gas," he said. "So if the old systemwas more than 99 percent water and less than 1 percent CO2, now we cancompletely reverse that, and pump 97 percent CO2 gas and only 3 percent watervapor into this system. Before those liquid water also functions as ionconductors in the system, and now we use ion exchange membranes instead to helpions move around without liquid water.

他说：“我们用水蒸气取代了液态水，并用高浓度的二氧化碳气体进料。” “因此，如果旧系统的水含量超过99％且二氧化碳含量低于1％，那么现在我们可以完全逆转这一点，并将97％的二氧化碳气体和仅3％的水蒸气泵入该系统。在此之前，液态水也起到离子的作用系统中的导体，现在我们使用离子交换膜来帮助离子在没有液态水的情况下四处移动。

"The impact is that we can deliver an order ofmagnitude higher current density," he continued. "Previously, we wereoperating at about ten milliamps-per-centimeter squared, but today we caneasily ramp up to 100 milliamps."

“如此我们便可以提供一个数量级更高的电流密度，”他继续说道。 “以前，我们的平均运行速度大约为10毫安/平方厘米，但今天我们可以轻松升至100毫安。”

Going forward, Wang said, the system still has challengesto overcome -- particularly related to stability.

Wang说，放眼未来，该系统仍有挑战需要克服,特别是与稳定性有关

"If you want to use this to make an economic orenvironmental impact, it needs to have a continuous operations of thousands ofhours," he said. "Right now, we can do this for tens of hours, sothere's still a big gap, but I believe those problems can be addressed withmore detailed analysis of both the CO2 reduction catalyst and the wateroxidation catalyst."

“如果你想利用它来产生经济或环境影响，它需要持续数千小时的操作，”他说。 “现在，我们可以做几十个小时，所以仍然存在很大差距，但我相信这些问题可以通过对二氧化碳减排催化剂和水氧化催化剂进行更详细的分析来解决。”

Ultimately, Wang said, the day may come when industrywill be able to capture the CO2 that is now released into the atmosphere andtransform it into useful products.

王说，最终，工业将能够捕获现在释放到大气中的二氧化碳，并将其转化为有用的产品。

"Carbon monoxide is not a particularly high valuechemical product," Wang said. "To explore more possibilities, my grouphas also developed several copper-based catalysts that can further reduce CO2 intoproducts that are much more valuable."

“一氧化碳不是一种特别高价值的化学产品，”王说。 “为了探索更多的可能性，我的团队还开发了几种铜基催化剂，可以进一步将二氧化碳减少为更有价值的产品。”

Wang credited the freedom he enjoyed at the Rowland Institutefor helping lead to breakthroughs like the new system.

他将自己在罗兰学院享有的自由归功于新系统的突破。

"Rowland has provided me, as an early careerresearcher, a great platform for independent research, which initiates a largeportion of the research directions my group will continue to pushforward," said Wang, who recently accepted a position at Rice University."I will definitely miss my days here."

“作为一名早期职业研究人员，罗兰为我提供了一个独立研究的绝佳平台，该平台启动了我的小组将继续推进的大部分研究方向，”最近接受赖斯大学职位的王说。 “我一定会想念我在这里的日子。”

科技词汇

Gas 气体

Spew 喷涌

Dioxide 二氧化物

Fuel 燃料

Monoxide 一氧化物

Copper 铜

Sustainable 可持续

Electrolyte 电解物

Chamber 室、腔

Nickel 镍

Catalyst 催化剂

Graphene 石墨烯

Alternative 替代物

Electrostatic 静电的

Gram 克

Batch 批

Diffuse 扩散

Voltage 电压

互动问答

本期：迷你数独

每个谜题都由一个在不同位置给与提示数字的4x4或6x6 格组成。游戏的目的是将空方格填上数字1到4（对于4x4大小的谜题）或者1到6（对于6x6的谜题），使得每一行，每一列以及每一个宫都没有重复的数字出现。

本期难度：Moderate

（答案见下期）

上期互动答案

上期 章：国际范摘要如何写——Nature杂志11月论 摘要示例二则

注： 数独是一种源自 18 世纪末的瑞士数学家欧拉所创造的拉丁方块游戏。传数独源起于拉丁方阵（ Latin Square ）， 1970 年代在美国发展，改名为数字拼图（ Number Place ）、之后流传至日本并发扬光大，以数学智力游戏智力拼图游戏发表。在 1984 年一本游戏杂志《パズル通信ニコリ》正式把它命名为数独，意思是“在每一格只有一个数字”。后来一位前任香港高等法院的新西兰籍法官高乐德（ Wayne Gould ）在 1997 年 3 月到日本东京旅游时，无意中发现了。他首先在英国的《泰晤士 》上发表，不久其他 纸也发表，很快便风靡全英国，之后他用了 6 年时间编写了电脑程式，并将它放在 站上，使这个游戏很快在全世界流行