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Category: chemistry – Page 42

Serendipitous discovery reveals how stress and chemistry etch mysterious spiral patterns

UCLA doctoral student Yilin Wong noticed that some tiny dots had appeared on one of her samples, which had been accidentally left out overnight. The layered sample consisted of a germanium wafer topped with evaporated metal films in contact with a drop of water. On a whim, she looked at the dots under a microscope and couldn’t believe her eyes. Beautiful spiral patterns had been etched into the germanium surface by a chemical reaction.

Wong’s curiosity led her on a journey to discover what no one had seen before: Hundreds of near-identical spiral patterns can spontaneously form on a centimeter square germanium chip. Moreover, small changes in experiment parameters, such as the thickness of the metal film, generated different patterns, including Archimedean spirals, logarithmic spirals, lotus flower shapes, radially symmetric patterns and more.

The discovery, published in Physical Review Materials, occurred fortuitously when Wong made a small mistake while attempting to bind DNA to the metal film.

Artificial photosynthesis converts organic waste into useful pharmaceuticals and energy

A research team led by Assistant Professor Shogo Mori and Professor Susumu Saito at Nagoya University has developed a method of artificial photosynthesis that uses sunlight and water to produce energy and valuable organic compounds, including pharmaceutical materials, from waste organic compounds. This achievement represents a significant step toward sustainable energy and chemical production.

The findings were published in Nature Communications.

“Artificial photosynthesis involves that mimic the way plants convert sunlight, water, and carbon dioxide into energy-rich glucose,” Saito explained. “Waste products, which are often produced by other processes, were not formed; instead, only energy and useful chemicals were created.”

Artificial enzyme splits water more efficiently

Mankind is facing a central challenge: It must manage the transition to a sustainable and carbon dioxide-neutral energy economy.

Hydrogen is considered a promising alternative to fossil fuels. It can be produced from water using electricity. If the electricity comes from , it is called green . But it would be even more sustainable if hydrogen could be produced directly with the energy of sunlight.

In nature, light-driven water splitting takes place during photosynthesis in plants. Plants use a complex molecular apparatus for this, the so-called photosystem II. Mimicking its active center is a promising strategy for realizing the sustainable production of hydrogen. A team led by Professor Frank Würthner at the Institute of Organic Chemistry and the Center for Nanosystems Chemistry at Julius-Maximilians-Universität Würzburg (JMU) is working on this.

Discarding a long-standing pessimistic hypothesis to rescue next-generation lithium-ion battery technology

In a megascience-scale collaboration with French researchers from College de France and the University of Montpellier, Skoltech scientists have shown a much-publicized problem with next-generation lithium-ion batteries to have been induced by the very experiments that sought to investigate it. Published in Nature Materials, the team’s findings suggest that the issue of lithium-rich cathode material deterioration should be approached from a different angle, giving hope for more efficient lithium-ion batteries that would store some 30% more energy.

Efficient energy storage is critical for the transition to a low-carbon economy, whether in grid-scale applications, electric vehicles, or portable devices. Lithium-ion batteries remain the best-developed electrochemical storage technology and promise further improvements. In particular, next-generation batteries with so-called lithium-rich cathodes could store about one-third more energy than their state-of-the-art counterparts with cathodes made of lithium nickel manganese cobalt oxide, or NMC.

A key challenge hindering the commercialization of lithium-rich batteries is voltage fade and capacity drop. As the battery is repeatedly charged and discharged in the course of normal use, its cathode material undergoes degradation of unclear nature, causing gradual voltage and capacity loss. The problem is known to be associated with the reduction and oxidation of the in NMC, but the precise nature of this redox process is not understood. This theoretical gap undermines the attempts to overcome voltage fade and bring next-generation batteries to the market.

Nanotube separation technique advances precise sensors for continuous health monitoring

Researchers at the University of Turku, Finland, have succeeded in producing sensors from single-wall carbon nanotubes that could enable major advances in health care, such as continuous health monitoring. Single-wall carbon nanotubes are nanomaterial consisting of a single atomic layer of graphene.

A long-standing challenge in developing the material has been that the nanotube manufacturing process produces a mix of conductive and semi-conductive nanotubes which differ in their chirality, i.e., in the way the graphene sheet is rolled to form the cylindrical structure of the nanotube. The electrical and chemical properties of nanotubes are largely dependent on their chirality.

Han Li, Collegium Researcher in materials engineering at the University of Turku, has developed methods to separate nanotubes with different chirality. In the current study, published in Physical Chemistry Chemical Physics, the researchers succeeded in distinguishing between two carbon nanotubes with very similar chirality and identifying their typical electrochemical properties.

Lithium needed for the battery revolution could be harvested from saltwater lakes thanks to a new membrane

Demand for lithium is rising due to its use in batteries for mobile devices, cars and clean energy storage. Securing access to natural deposits of the mineral is now a matter of strategic importance, but lithium can be found elsewhere in nature.

As an alternative to mining, Imperial researchers have created a technology that could be used to efficiently extract it from saltwater sources such as salt-lake brines or geothermal brine solutions.

Conventional extraction from brines takes months and uses significant amounts of water and chemicals, generating greenhouse gas emissions in the process. The alternative developed by Dr. Qilei Song and his team in the Department of Chemical Engineering uses a membrane that separates lithium from by filtering it through tiny pores.

Scientists Discover New Heavy-Metal Molecule ‘Berkelocene’

A research team led by the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has discovered “berkelocene,” the first organometallic molecule to be characterized containing the heavy element berkelium.

Organometallic molecules, which consist of a metal ion surrounded by a carbon-based framework, are relatively common for early actinide elements like uranium (atomic number 92) but are scarcely known for later actinides like berkelium (atomic number 97).

“This is the first time that evidence for the formation of a chemical bond between berkelium and carbon has been obtained. The discovery provides new understanding of how berkelium and other actinides behave relative to their peers in the periodic table,” said Stefan Minasian, a scientist in Berkeley Lab’s Chemical Sciences Division and one of four co-corresponding authors of a new study published in the journal Science.

Breakthrough in heavy-element chemistry shatters long-held assumptions about transuranium elements.