University of Michigan develops efficient system for converting CO2 into ethylene

by Clarence Oxford

Los Angeles CA (SPX) Sep 19, 2024

Researchers at the University of Michigan have made a significant advancement toward creating sustainable fuels by developing an artificial photosynthesis system that efficiently chains carbon atoms together. The system is capable of converting carbon dioxide into ethylene, a critical hydrocarbon used in plastics, with field-leading efficiency, yield, and longevity.

“The performance, or the activity and stability, is about five to six times better than what is typically reported for solar energy or light-driven carbon dioxide reduction to ethylene,” said Zetian Mi, a professor of electrical and computer engineering at the University of Michigan and the corresponding author of the study, which was published in ‘Nature Synthesis’.

Ethylene, the most widely produced organic compound in the world, is traditionally created using oil and gas under high temperatures and pressures – processes that contribute significantly to carbon dioxide emissions. By utilizing this new photosynthesis system, it may become possible to produce ethylene without adding to atmospheric CO2 levels.

The long-term goal of the research team is to develop a process that chains more carbon and hydrogen atoms together, potentially leading to the creation of liquid fuels, which are easier to transport and could support sustainable energy solutions.

The device created by the Michigan team uses two types of semiconductors: a base layer of silicon with gallium nitride nanowires grown on top. These nanowires, each just 50 nanometers wide, are dotted with copper clusters that catalyze the conversion of water and carbon dioxide into ethylene.

When exposed to light, the semiconductors generate electrons that break apart water molecules, producing hydrogen for the reaction. The copper clusters then facilitate the bonding of carbon atoms from carbon dioxide into carbon monoxide, eventually leading to the creation of ethylene.

The device stands out not only for its efficiency but also for its durability. While previous systems lasted only a few hours, the Michigan team’s device ran continuously for 116 hours without losing performance. Some earlier iterations have operated for up to 3,000 hours. This longevity is attributed to the synergistic effects between gallium nitride and the water-splitting process, which leads to self-healing of the catalyst over time.

Looking ahead, the research team plans to explore ways to extend the process to create other multicarbon compounds, including propanol, as they work toward the ultimate goal of producing sustainable liquid fuels.

“In the future, we want to produce some other multicarbon compounds such as propanol with three carbons or liquid products,” said Bingxing Zhang, assistant research scientist at U-M and first author of the paper.

Research Report:Interfacially coupled Cu-cluster/GaN photocathode for efficient CO2 to ethylene conversion

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Second life of lithium-ion batteries may propel future space missions

by Robert Schreiber

Berlin, Germany (SPX) Sep 19, 2024

Lithium-ion battery usage worldwide has doubled in the past four years, contributing to a growing volume of hazardous battery waste. This rise underscores the urgent need for more effective recycling solutions. Scientists from several Polish research institutions, including Bydgoszcz University of Science and Technology (PBS), the Institute of Fundamental Technological Research of the Polish Academy of Sciences, the Institute of Physical Chemistry of the PAS in Warsaw, and Wroclaw University of Science and Technology, have introduced a promising approach in the journal ‘ChemElectroChem’.

The research focused on carbon materials extracted from the electrodes of spent lithium-ion batteries (LIBs). The team employed an acidic leaching process to recover valuable metals from these electrodes. Depending on experimental conditions, the extracted carbon materials retained trace amounts of metals like cobalt, commonly used in catalysis. The goal was to repurpose these materials for use in catalytic processes, with a particular emphasis on hydrogen peroxide production.

“Hydrogen peroxide is one of the fundamental chemical molecules, essential to numerous industries. Large-scale production of this substance typically demands high pressures and temperatures, costly catalysts, and various toxic electrolytes. Our focus was on developing a more environmentally friendly method for producing hydrogen peroxide: specifically, an electrochemical approach using catalysts derived from used lithium-ion batteries,” explains Dr. Eng. Magdalena Warczak (PBS), project leader and lead author.

The team’s electrochemical tests demonstrated that carbon nanostructures and cobalt recovered from the batteries exhibited catalytic properties for the oxygen reduction reaction. However, these properties were influenced by the composition and structure of the sample, which were determined by the types of etching baths used to clean the extracted electrodes.

“For potential future applications, the crucial finding is that, based on data gathered from experiments using a rotating electrode, we were able to determine the number of electrons involved in the reduction of a single oxygen molecule. The electrochemical reduction of oxygen can occur with either four or two electrons. In the case of four electrons, water is produced, but with two electrons, we obtain the desired hydrogen peroxide. In all the samples we tested, we observed the two-electron reduction,” explains Dr. Warczak.

To ensure accuracy, the measurements were repeated with battery powders suspended between two immiscible liquids, eliminating any influence from the glassy carbon electrode. The oxygen reduction reaction occurred spontaneously at the interface of these liquids, with the organic liquid containing decamethylferrocene, an electron donor. These experiments confirmed that all samples catalyzed the production of hydrogen peroxide, with concentrations measured by a scanning electrochemical microscope showing levels one to two orders of magnitude higher than those in systems without battery waste.

“Lithium-ion batteries have generally been viewed as just a secondary source of carbon materials, mainly graphite, and metals like lithium, cobalt, or nickel. Meanwhile, our group’s findings clearly demonstrate that battery waste can catalyze the reduction of oxygen to hydrogen peroxide, and in the future, this could lead to its use in producing this important chemical compound,” concludes Dr. Warczak.

Hydrogen peroxide, commonly found in pharmacies at a 3% concentration for disinfecting wounds, has a range of industrial applications. Solutions with up to 15% concentration are used in household cleaning products and cosmetics, while concentrations of around 30% are vital in industries such as chemical manufacturing, pulp and paper, textiles, electronics, and food processing. Hydrogen peroxide also serves as an oxidizer for fuels, including rocket propellants. During the 1940s, it was first used in early rockets capable of reaching space. Recently, hydrogen peroxide at concentrations exceeding 98% powered a suborbital rocket built by the Lukasiewicz Institute of Aviation in Warsaw.

The research on hydrogen peroxide production from spent lithium-ion batteries, initially funded by a SONATA grant from the Polish National Science Centre, will continue with a focus on enhancing the efficiency of electrochemical reactions for industrial use. The team also plans to explore four-electron reduction for potential applications in fuel cells.

Research Report:Insights into the High Catalytic Activity of Li-ion Battery Waste Toward Oxygen Reduction to Hydrogen Peroxide

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Solar on track for another record year: report

by AFP Staff Writers

Paris (AFP) Sept 18, 2024

The solar industry is due to grow by nearly a third in 2024, beating forecasts as it adds 593 gigawatts of additional capacity, the majority of them in China, according to a report released on Thursday by the Ember think tank.

“This is a 29 percent increase compared to the previous year, maintaining strong growth following an estimated 87 percent surge in 2023,” the report said.

“Yet again, solar power is growing faster than people expected, as it establishes itself as the cheapest source of electricity globally,” said Euan Graham, electricity data analyst at Ember.

Illustrating the lightning speed at which solar is growing, Ember projections show that new solar capacity added in 2024 alone will be more than the 540 GW of additional coal power added around the world since 2010.

China remains the world leader in the sector and is expected to add 334 GW, or 56 percent of the world total in 2024.

It is followed by the United States, India, Germany and Brazil, with the top five countries accounting for 75 percent of the new solar capacity in 2024, the report said.

Grid capacity and battery storage were key to maintaining growth in the sector, the report said.

“As solar becomes more affordable and accessible, ensuring sufficient grid capacity and developing battery storage is crucial for handling power distribution and supporting solar outside of peak sunlight hours,” it said.

“By addressing these challenges and sustaining growth, solar power could continue to exceed expectations for the remainder of the decade.”

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