国外:二氧化碳被直接转化成甲醇效率达79%
2016-01-30 12:33:22 来源：科技日报评论：0 点击：

诺贝尔化学奖获得者、南加利福尼亚大学化学系教授乔治·欧拉率领团队,首次采用基于金属钌的催化剂,将从空气中捕获的二氧化碳直接转化为甲醇燃料,转化率高达79%。

　　科技日报北京1月29日电（记者华凌）诺贝尔化学奖获得者、南加利福尼亚大学化学系教授乔治·欧拉率领团队，首次采用基于金属钌的催化剂，将从空气中捕获的二氧化碳直接转化为甲醇燃料，转化率高达79%。该研究向通往未来“甲醇经济”迈出了重要一步。相关研究成果刊登在最新一期《美国化学学会杂志》上。

　　南加利福尼亚大学化学教授叙利娅·普拉卡什说：“直接在捕获二氧化碳的气罐中用氢分子将其转换为甲醇，我们率先做到了！”该研究既可去除大气中的温室气体二氧化碳，生成的甲醇还能作为汽油的替代燃料。

　　过去几年，化学家们一直在研究把二氧化碳转化为有用产品的各种方法，例如，用氢气处理二氧化碳生产出甲醇、甲烷或甲酸。因可在燃料电池中作为替代燃料以及用于氢存储，如何将二氧化碳转化为甲醇的研究最受青睐。

　　二氧化碳转化成甲醇过程中的一个关键因素是找到合适的均相催化剂，这对于加快化学反应生产甲醇至关重要。但问题是，转化反应需要的高温（约150℃）条件，往往会导致催化剂的分解。

　　据物理学家组织网报道，此次研究人员开发出在高温下不会分解的金属钌催化剂，稳定性好，可重复使用，并可连续生产甲醇。研究表明，用新的催化剂及一些额外的化合物，可将从空气中捕获的二氧化碳转换为甲醇的效率提高到79%。在最初过程中，甲醇会与水混合，但水很容易通过蒸馏分离。

　　研究人员希望这项工作未来能为“甲醇经济”做出贡献，并计划开发出一个“人为的碳循环”，其中碳被回收利用，以补充自然界碳的循环。

文章英文原文及地址：http://phys.org/news/2016-01-carbon-dioxide-captured-air-methanol.html

(Phys.org)—For the first time, researchers have demonstrated that CO2 captured from the air can be directly converted into methanol (CH3OH) using a homogeneous catalyst. The benefits are two-fold: The process removes harmful CO2 from the atmosphere, and the methanol can be used as an alternative fuel to gasoline. The work represents an important step that could one day lead to a future "methanol economy," in which fuel and energy storage are primarily based on methanol.

The study was led by G. K. Surya Prakash, a chemistry professor at the University of Southern California, along with the Nobel laureate George A. Olah, a distinguished professor at the University of Southern California. The researchers have published their paper on the CO2-to-methanol conversion process in a recent issue of the Journal of the American Chemical Society.

"Direct CO2 capture and conversion to methanol using molecular hydrogen in the same pot was never achieved before. We have now done it!" Prakash told Phys.org.

Over the past several years, chemists have been investigating various ways of recycling CO2 into useful products. For example, treating CO2 with hydrogen gas (H2) can produce methanol, methane (CH4), or formic acid (HCOOH). Among these products, methanol is especially attractive because of its use as an alternative fuel, in fuel cells, and for hydrogen storage.

The chemical industry currently produces more than 70 million tons of methanol annually because the simple compound also serves as a building block for many larger compounds, including two of the most highly produced organic compounds, ethylene and propylene, which are used to make plastics and other products.

A key factor in the CO2-to-methanol conversion process is finding a good homogeneous catalyst, which is essential for speeding up the chemical reactions so that methanol can be produced at a fast rate. The problem is that these reactions require high temperatures (around 150 °C), and unfortunately the heat often causes the catalysts to decompose.

In the new study, the researchers developed a stable catalyst based on the metal ruthenium that does not decompose at high temperatures. The catalyst's good stability allows it to be reused over and over again for the continuous production of methanol.

"Developing stable homogeneous catalysts for CO2 reduction to methanol was a challenge," Prakash said. "Majority of the catalysts stopped at the formic acid stage. Furthermore, we needed a catalyst that could reduce carbamates or alkylammonium bicarbonates directly to methanol. We have achieved both with our catalyst."

With the new catalyst, along with a few additional compounds, the researchers demonstrated that up to 79% of the CO2 captured from the air can be converted into methanol. Initially the methanol is mixed with water, but it can be easily separated out by distillation.

Looking at the work from a broader perspective, the researchers hope that it may one day contribute to a methanol economy. This plan involves developing an "anthropogenic carbon cycle" in which carbon is recycled to supplement the natural carbon cycle. In nature, carbon is continuously being exchanged, recycled, and reused among the atmosphere, oceans, and living organisms, but nature cannot recycle the carbon from fossil fuels as quickly as humans can burn them. Humans could counteract some of the CO2 we release by converting some of the carbon back into an energy source such as methanol.

More information on the anthropogenic carbon cycle can be found in this Perspective piece by Olah, Prakash, and Alain Goeppert.

As a next step, the researchers plan to lower the catalyst operating temperature and improve its efficiency.

"We will continue the studies to develop more robust catalysts that work around 100 to 120 °C," Prakash said. "We would like to perform the chemistry in a preparatively useful way, wherein there are no solvent or reagent losses."

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国外:二氧化碳被直接转化成甲醇效率达79%
2016-01-30 12:33:22 来源：科技日报评论：0 点击：

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国外:二氧化碳被直接转化成甲醇效率达79%
2016-01-30 12:33:22 来源：科技日报评论：0 点击：