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Motivated to turn greenhouse gases like carbon dioxide into high value chemicals like methanol, EPFL chemical engineers have developed a new method to make catalysts. Catalysts are major tools in the chemical industry and are largely made to make petrochemicals. In this method, they have developed a way to build—with near atomic precision—metal clusters on solid supports that have the potential to improve catalytic activity. The results are published in Nature Catalysis. "You want to produce as much product per time per catalyst as possible, and we've found that when a catalyst is prepared with near atomic precision, you get a more active material," says Jeremy Luterbacher, professor at EPFL's Laboratory of Sustainable and Catalytic Processing. "This technique is particularly interesting for difficult reactions like that of carbon dioxide with hydrogen gas for producing renewable methanol."

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In a recent collaboration, a research team developed a hydrogen evolution reaction catalyst that minimizes degradation caused by reverse current in alkaline water electrolysis systems. The team consists of Professor Yong-Tae Kim, Dr. Sang-Mun Jung, and Yoona Kim, an MSc, from the Department of Materials Science and Engineering at Pohang University of Science and Technology (POSTECH) and is led by Professor Jeong Woo Han from Seoul National University. Their research was published as a cover paper in the journal Advanced Functional Materials on July 3. The electricity generated from the renewable energy sources such as solar, wind, hydro, and geothermal are not constant; it fluctuates with weather and climate conditions. To harness and utilize this energy, it must be reliably stored and delivered to the grid, and hydrogen plays a crucial role in this process.

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A research team led by Prof. Chen Changlun from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences, together with collaborators, developed advanced cobalt-doped nickel hydroxide bipolar electrodes and non-noble metal catalysts, which significantly improved the efficiency and stability of two-step water electrolysis for hydrogen production. The results were published in the Chemical Engineering Journal and the Journal of Colloid and Interface Science. Traditional alkaline electrolyzers face problems such as mismatch with fluctuating renewable energy sources and hydrogen/oxygen mixing under high pressure, which limit their applications. Two-step water electrolysis overcomes these problems by completely separating hydrogen and oxygen production in time and space using a bipolar electrode, eliminating the need for a costly membrane separator.

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A new catalyst made from an inexpensive, abundant metal and common table sugar has the power to destroy carbon dioxide (CO2) gas. In a new Northwestern University study, the catalyst successfully converted CO2 into carbon monoxide (CO), an important building block to produce a variety of useful chemicals. When the reaction occurs in the presence of hydrogen, for example, CO2 and hydrogen transform into synthesis gas (or syngas), a highly valuable precursor to producing fuels that can potentially replace gasoline. With recent advances in carbon capture technologies, post-combustion carbon capture is becoming a plausible option to help tackle the global climate change crisis. But how to handle the captured carbon remains an open-ended question. The new catalyst potentially could provide one solution for disposing of the potent greenhouse gas by converting it into a more valuable product.

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Crown ethers were discovered in 1967. They were then modified by adding a metal-containing unit, creating metallacrown ethers. These metallacrown ethers have been the subject of intensive research. Depending on the molecular makeup of the metallacrown ethers and their resultant architecture, the properties and, therefore, the uses of the metallacrowns can change. They have many different uses currently, and ongoing studies continue to expand their application. Just a few of these include magnetic refrigeration, imaging agents—specifically as potential contrast agents in magnetic resonance imaging—and single-molecular magnetism, which is being explored for its use in quantum computing. More specifically, "metallacrown ethers have recently attracted considerable attention because they selectively capture guest species, especially metal ions and organic ammonium cations. And this characteristic may increase its utility in catalysis, magnetism, and proton conductors," said Dr. Xiao, the paper's lead author and a scientific researcher at the Department of Chemistry at Tsinghua University, Beijing.

CO2 hydrogenation with green hydrogen is one of the best processes to combat climate change and can provide a single solution to three challenging problems, 1) excessive CO2 levels, 2) the temporal mismatch between solar electricity production and demand, and 3) hydrogen gas storage. However, the CO2 hydrogenation reaction needs very high temperatures, causing quick deactivation of the catalyst.

In new work published in ACS Nano, researchers at Tata Institute of Fundamental Research (TIFR), Mumbai, asked the question of whether this high-temperature CO2hydrogenation can be catalyzed at room to moderate temperature via plasmonic excitation of H2 and CO2 using plasmonic catalyst. They have demonstrated that plasmonic black gold-nickel efficiently catalyzes CO2 hydrogenation using visible light.

The reaction took place as low as 84 to 223°C without external heating. Researchers found a multifold increase in the catalytic activity as compared to DPC-C4 to the extent that measurable photoactivity was only observed with DPC-C4-Ni. It showed the best-reported CO production rate of 2464± 40 mmol gNi-1 h-1 and selectivity greater than 95% in the flow conditions. The catalyst showed extraordinary stability (100 h).