艾姆斯国家实验室、爱荷华州立大学、弗吉尼亚大学和哥伦比亚大学的科学家们日前开发出了一种将二氧化碳转化为乙烯的新型混合催化剂
新型混合催化剂只使用地球上储量丰富的材料，如镍和铜，这种催化剂反应所需的能量更少
新型混合催化剂的多孔结构和两种催化剂的组合使其在二氧化碳还原为一氧化碳和一氧化碳还原为乙烯反应中具有高效性和选择性
据油价网2023年1月31日报道，爱荷华州立大学艾姆斯国家实验室日前宣布了一种新型混合催化剂，可以在一个罐子里将二氧化碳转化为乙烯。这种新型混合催化剂是由来自艾姆斯国家实验室、爱荷华州立大学、弗吉尼亚大学和哥伦比亚大学的科学家们开发的。这种催化剂通过将二氧化碳回收作为高效乙烯生产的原料，支持世界净零排放碳倡议。
这个团队的报告论文日前已经发表在《美国化学学会杂志》上。
乙烯是一种作为大宗商品的化学制品，用于制造从塑料到防冻剂的各种产品。乙烯的大规模生产是能源密集型的，严重依赖化石资源。二氧化碳电催化制乙烯是一种很有前途的方法。这种新型混合催化剂只由地球上储量丰富的材料组成，如镍和铜，它们的化学反应所需的能量更少。
艾姆斯国家实验室的科学家齐龙（音译）解释了新型混合催化剂的工作原理。
原子分散的镍锚定在氮组装碳(NAC)上，在低电压和大电流下催化二氧化碳生成一氧化碳。这种新型混合催化剂在宽电压范围内有效，在更高电流下的有效性意味着更高的一氧化碳生产速率。
齐龙指出：“由于这种新型混合催化剂在非常宽的电压范围内保持活性，因此很容易与第二种催化剂耦合。所以我们使用第二种催化剂，这是一种铜纳米线，通过结合这两种催化剂，我们有一个非常具选择性的过程，在一个罐子里从二氧化碳到乙烯的效率高达60%。”
催化剂的另一个重要方面是它的结构。艾姆斯国家实验室科学家、爱荷华州立大学教授黄文宇(音译)指出，这种新型混合催化剂的多孔结构增强了其有效性。他说：“我们的催化剂具有有序的介孔结构，有利于传质。因为它是高度多孔的，你有一个非常大的表面积来暴露大量的镍的活性位点，这使得我们的催化剂在将二氧化碳转化为一氧化碳方面非常有效。”
黄文宇说，这项研究最令人兴奋的方面是团队如何结合两种催化剂来简化过程。他说：“我们基本上把两种最好的催化剂单独结合在一起，它们一起工作，所以我们可以在一个系统中把二氧化碳连接到一氧化碳以及把一氧化碳连接到乙烯的反应。”
齐龙强调了使用二氧化碳作为这种反应的原料的重要性，因为它解决了全球减少二氧化碳排放到大气中的需求。他解释说，这个过程可以使用从化学或工业过程中回收的二氧化碳，或者从空气捕获中回收的二氧化碳。齐龙说：“我们可以在没有任何贵金属的情况下做到这一点，只需镍、铜、碳和氮，就可以实现大规模的工业应用。”“此外，我们可能不再使用化石燃料来生产乙烯。”
看起来总有一天二氧化碳供应会出现竞争。这是另一个利用二氧化碳的突破性技术。早在去年12月，就有一篇关于废气捕集器用来制造乙烯的报道。
新闻稿中缺少的是氢气的来源。这篇论文的摘要提供了催化剂在碱性流动池中运行，这可能需要补水。
但如上所述，乙烯是一种作为大宗商品的化学制品，几乎在任何地方都有成千上万吨的用量。然而，多样化的供应看起来是一件好事。就目前而言，乙烯既不短缺，也不特别昂贵。看看什么才是真正具有经济竞争力并获得一些市场份额的产品，将是一件很有趣的事情。
李峻 编译自 油价网
原文如下：
New Carbon Conversion Tech Could Boost Net-Zero Initiative
· A new hybrid catalyst for converting carbon dioxide into ethylene has been developed by Ames Laboratory, Iowa State University, University of Virginia, and Columbia University.
· The catalyst uses only earth-abundant materials such as nickel and copper and requires less energy for chemical reactions.
· The catalyst's porous structure and combination of two catalysts make it highly effective and selective in CO2 reduction to CO and CO to ethylene reactions.
The Ames Laboratory at Iowa State University has announced a new hybrid catalyst that converts carbon dioxide into ethylene in one pot. The catalyst was developed by scientists from Ames National Laboratory, Iowa State University, University of Virginia, and Columbia University. This catalyst supports the world net-zero carbon initiative by using carbon dioxide (CO2) recycling it as a feedstock for efficient ethylene production powered by electricity.
The team’s reporting paper has been published in the Journal of the American Chemical Society.
Ethylene is a commodity chemical used to manufacture a wide range of products from plastics to antifreeze. The large-scale production of ethylene is energy intensive and relies heavily on fossil resources. Electrocatalytic production of ethylene from CO2 is emerging as a promising method. This new catalyst consists of only earth-abundant materials, such as nickel and copper, and requires less energy for chemical reaction.
Long Qi, a scientist at Ames Lab, explained how the catalyst works.
Atomically dispersed nickel anchored on nitrogen assembly carbon (NAC) works to catalyze CO2 to CO at low voltage and high current. The catalyst is effective over a wide range of voltages and its effectiveness at higher currents means a higher rate of CO production.
Qi noted, “Since this catalyst remains active over a very wide voltage range, that allows easy coupling with a second catalyst. So we use the second catalyst, which is a copper nanowire, and by combining these two we have a very selective process that has up to 60% efficiency going from CO2 to ethylene in one pot.”
Another important aspect of the catalyst is its structure. Wenyu Huang, an Ames Lab scientist and Iowa State University professor from the team, noted that the catalyst’s porous structure enhances its effectiveness. “Our catalyst has an ordered mesoporous structure that is beneficiary for mass transfer,” he said. “Because it’s highly porous, you have a very high surface area to expose a lot of nickel’s active sites, making our catalyst very effective in CO2 reduction to CO.”
For Huang, the most exciting aspect of this research was how the team combined the two catalysts to streamline the process. “We basically combine the two best catalysts on their own, and they work together so we can connect the CO2 to CO and the CO to ethylene reactions in one system,” he said.
Qi emphasized the importance of using CO2 as a feedstock for this reaction, because it addresses the global need to reduce the amount of CO2 released into the atmosphere. He explained that this process can use CO2 recovered from chemical or industrial processes, or from air capture. “And we can do this without any precious metal, simply the nickel, copper, carbon, and nitrogen, to permit large-scale industrial applications,” Qi said. “Also, we potentially eliminate the use of fossil resources to make ethylene.”
It looks like there will be some competition for CO2 supplies someday. This is another breakout technology to make use of CO2. Back in December there was a report about a flue gas trap set up to make ethylene.
What’s missing in the press release is the source for the hydrogen. The abstract for the paper offers that the catalyst operates in an alkaline flow cell, which presumably needs water replenishment.
But as noted, ethylene is a commodity chemical that is used by the thousands of tons almost everywhere. Yet a diversified supply looks like a good thing. For now, ethylene is hardly in short supply or particularly expensive. It will be interesting to see what is actually economically competitive and gets some market share.
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