catalysts

Making hydrogen using bioengineering

February 28, 2025 By EarthWise Leave a Comment

Hydrogen has great potential for helping society to reach net-zero emissions. The problem is that the most economical and established production methods for hydrogen depend heavily on fossil fuels and result in roughly a dozen kilograms of carbon dioxide emissions for every kilogram of hydrogen produced.

The carbon-free way to produce hydrogen is by splitting water into its component elements. This process generally requires the use of catalysts and lots of energy.

Researchers at the University of Oxford are developing a synthetic biology approach to the production of so-called green hydrogen. The idea is to replace expensive, exotic metal-based catalysts with a highly-efficient, stable, and cost-effective catalyst based on genetically-engineered bacteria.

There are specific microorganisms that can naturally induce the chemical reaction that reduces protons to hydrogen by the use of hydrogenase enzymes. While these reactions do occur naturally, they are limited to low hydrogen yields.

The Oxford researchers genetically engineered the bacterium Shewanella oneidensis by inserting a light activated electron pump called Gloeobacter rhodopsin as well as adding nanoparticles of graphene oxide and ferric sulfate. All of this tinkering with the bacterium resulted in a ten-fold increase in hydrogen yield.

The researchers believe that their system, based entirely on biological methods rather than traditional chemical approaches, could be scaled up to produce ‘artificial leaves’ that, when exposed to sunlight, would immediately begin producing hydrogen. The Oxford work was published last summer in the Proceedings of the National Academy of Science.

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A green fuels breakthrough: bio-engineering bacteria to become ‘hydrogen nanoreactors’

Photo, posted July 27, 2016, courtesy of Blondinrikard Froberg via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Fertilizer from thin air

January 16, 2025 By EarthWise Leave a Comment

Ammonia is one of the largest-volume synthetic chemicals produced in the world. Globally, manufacturing plants produce about 200 million tons of it each year. About 70% of ammonia is used to produce fertilizers.

Most ammonia is produced using the Haber-Bosch process, which converts hydrogen and nitrogen into ammonia. The process is energy-hungry, running at over 900 degrees Fahrenheit, and therefore results in lots of greenhouse gas emissions – about 1% of the world’s annual CO2 emissions.

Researchers at Stanford University and King Fahd University in Saudi Arabia have developed a prototype device that can produce ammonia using wind energy to draw air through a mesh. The method allows sustainable production of ammonia using the nitrogen in the air.

The process gets nitrogen from the air along with hydrogen from water vapor. A mesh coated with catalysts facilitates the necessary chemical reactions. The process operates at room temperature and standard atmospheric pressure, eliminating the need for the high temperatures and high pressures of the Haber-Bosch process.

In principle, farmers could run a portable device onsite, eliminating the need to purchase and ship fertilizer from a manufacturer.

The device is two or three years away from being market ready. The developers are designing increasingly large mesh systems to produce greater quantities of ammonia. Ammonia has more uses beyond fertilizers including its use as an energy carrier that can store and transport energy more efficiently than hydrogen gas.

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New device produces critical fertilizer ingredient from thin air, cutting carbon emissions

Photo, posted September 2, 2013, courtesy of Chafer Machinery via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A better way to produce green hydrogen

September 9, 2024 By EarthWise Leave a Comment

Hydrogen has great potential as a fuel and an energy carrier for many applications. Burning it or consuming it in fuel cells does not produce carbon emissions. As a result, there has long been the vision for a future hydrogen economy. Whether the hydrogen economy would ever come about given how various other technologies have evolved over time is questionable. But regardless, hydrogen is valuable for many industrial and commercial applications including the manufacture of ammonia and the refining of metals.

Hydrogen is produced in industrial quantities from natural gas by a carbon-dioxide-producing process known as methane-steam reforming. To take its place as a green energy source, hydrogen needs to be produced by splitting water into its constituent oxygen and hydrogen components by the process of electrolysis.

The problem is economic. Methane-steam reforming produces hydrogen at a cost of about $1.50 per kilogram. Green hydrogen costs about $5 a kilogram.

Researchers at Oregon State University have developed a new photocatalyst that enables the high-speed, high-efficiency production of hydrogen. The material, called RTTA, is a metal organic framework containing ruthenium oxide and titanium oxide. Ruthenium oxide is expensive, but very little is needed. For industrial applications, if the catalyst shows good stability and reproducibility, the cost of the small amount of this exotic material becomes less important.

The photocatalyst, when exposed to sunlight, quickly and efficiently splits water yielding hydrogen. The Oregon State discovery has real potential.

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Oregon State University research uncovers better way to produce green hydrogen

Photo, posted July 7, 2023, courtesy of Bill Abbott via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Sustainable hydrogen from methane

February 14, 2024 By EarthWise Leave a Comment

Hydrogen could serve as a viable alternative to fossil fuels that can be used directly as a fuel or can be used to generate electricity to power cars and other devices. However, large-scale production of hydrogen currently relies on fossil fuels and creates carbon emissions in the process.

So-called green hydrogen involves using electricity to split water into its component elements to produce it. If the electricity is generated without emissions, then the hydrogen is truly green.

Another way to get hydrogen is by breaking down hydrocarbons like methane, which itself is a very powerful greenhouse gas. This so-called blue hydrogen could be environmentally friendly if an appropriate method for producing it can be developed.

Existing techniques for converting methane into hydrogen involve the use of metal catalysts – often nickel – that are energy-intensive to mine and manufacture, and can negatively affect the environment. Research at the University of Surrey in the UK has shown promising results for the use of nitrogen-doped nanocarbons as metal-free catalysts for the direct conversion of methane into hydrogen. One of the biggest problems with using metal catalysts for hydrogen production is that they get poisoned by carbon. The carbon that comes out of the methane ends up stopping the catalyst from continuing to do its chemical job. It turns out that the doped nanocarbon approach to hydrogen catalysis appears to be resistant to this problem.

The development of sustainable hydrogen production methods, including efficient and sustainable electrolysis of water as well as catalysis of hydrocarbons like methane, is crucial to realizing the potential of hydrogen fuel as a clean energy source.

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‘Game-changing’ findings for sustainable hydrogen production

Photo, posted April 30, 2021, courtesy of California Energy Commission via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Ending plastic separation anxiety

December 27, 2023 By EarthWise Leave a Comment

Petroleum-based plastics are one of the biggest environmental problems we face. They mostly end up in landfills – or worse, in the oceans and elsewhere in the environment – and they basically don’t decompose over time. Bio-based plastics were invented to help solve the plastic waste crisis. These materials do break down in the environment providing a potential solution to the problem. But it turns out that they can actually make plastic waste management even more challenging.

The problem is that bioplastics look and feel so similar to conventional plastics that they get mixed in with the petroleum-based plastics rather than ending up in composters, where they can break down as designed.

Mixtures of conventional and bioplastics end up in recycling streams where they get shredded and melted down, resulting in materials that are of very poor quality for making functional products. The only solution is to try to separate the different plastics at recycling facilities, which is difficult and expensive to do.

Scientists at Lawrence Berkeley National Laboratory, the Joint BioEnergy Institute, and the incubator company X have invented a simple “one pot” process to break down mixtures of different types of plastic using naturally derived salt solutions and specialized microbes and then produce a new type of biodegradable polymer that can be made into fresh commodity products.

The team is experimenting with various catalysts to find the optimum way to break down polymers at the lowest cost and are modeling how their processes can work at the large scales of real-world recycling facilities. Chemical recycling of plastics is a hot topic but has been difficult to make happen economically at the commercial scale.

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Putting an End to Plastic Separation Anxiety

Photo, posted November 28, 2016, courtesy of Leonard J Matthews via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

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Plastic From Sunlight | Earth Wise

March 13, 2023 By EarthWise Leave a Comment

Photosynthesis is the process that plants use to turn water, carbon dioxide, and energy from sunlight into plant biomass. It provides humans and much of animal life with food. Photosynthesis is also nature’s way of reducing the amount of carbon dioxide in the atmosphere. The CO2 is not directly stored in plants but rather is combined into organic compounds.

Researchers across the globe are trying to find effective ways to mimic photosynthesis. One version of artificial photosynthesis seeks to take carbon dioxide and combine it into organic compounds that can be used as raw materials for various kinds of manufacturing.

A research team in Japan has found a way to synthesize fumaric acid from carbon dioxide using sunlight to power the process. Fumaric acid is a chemical typically synthesized from petroleum and is used as a raw material for making biodegradable plastics such as polybutylene succinate.

Much of artificial photosynthesis research is aimed at using solar energy to convert carbon dioxide directly into a fuel rather than a raw material. Such solar fuels can be produced by a variety of means including thermochemical (using the sun’s heat to drive chemical reactions), photochemical (using the sun’s light to drive chemical reactions), and electrochemical (using solar-generated electricity to drive chemical reactions.) These approaches generally involve the use of specialized catalysts to drive the desired chemical reactions.

One way or another, what techniques for artificial photosynthesis have in common is trying to imitate what plant life on Earth has been doing for millions of years.

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Artificial photosynthesis uses sunlight to make biodegradable plastic

Photo, posted June 14, 2017, courtesy of Alex Holyake via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Turning Pollution Into Cash | Earth Wise

April 22, 2022 By EarthWise Leave a Comment

Power plants and other industrial facilities are a major source of carbon emissions. There are a variety of techniques under development to prevent those emissions by capturing them rather than releasing them into the atmosphere. All of them add costs to the functioning of the facility. A good way to offset those costs is to convert the emissions into useful products, ideally making it profitable to capture emissions.

Engineers at the University of Cincinnati have developed an electrochemical system that converts carbon dioxide into ethylene, which is a chemical used in a wide range of manufacturing. Ethylene has sometimes been called “the world’s most important chemical”. It is used in many kinds of plastics, textiles, and the rubber found in tires and insulation. It is also used in heavy industry such as steel and cement plants as well as in the oil and gas industry.

The Cincinnati process is a two-stage cascade reaction that converts carbon dioxide to carbon monoxide and then into ethylene. It is based on the underlying principle of the plug-flow reactor that is used for variety of production applications. The study, published in the journal Nature Catalysis, demonstrates that the process has high ethylene selectivity – meaning that it effectively isolates the desired compound – as well as high productivity – meaning that it makes a lot of it. The system will take more time to become truly economical, but the researchers are continuing to make progress on that front with improved catalysts.

The researchers believe that this technique can reduce carbon emissions and make a profit doing it. Power plants and other facilities emit a lot of carbon dioxide. With this process, it may be possible to capture it and produce a valuable chemical.

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Conversion process turns pollution into cash

Photo, posted February 27, 2018, courtesy of Cyprien Hauser via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Decarbonizing The Most Polluting Heavy Industries | Earth Wise

November 23, 2021 By EarthWise Leave a Comment

The production of steel, cement, and ammonia accounts for about 20% of the carbon dioxide humans pour into the atmosphere. Modern cities are largely constructed from concrete and steel and most of our food is grown using fertilizer made from ammonia.

The most widely discussed solutions to decarbonizing these industries are green hydrogen and carbon capture and storage or CCS.

Steel manufacture is responsible for 11% of society’s emissions. Most production starts by burning coal in a blast furnace. Using CCS could reduce emissions from burning the coal. But the blast furnace could be eliminated entirely by the use of electrolysis to produce the pure iron needed to make steel. This would be extremely energy-intensive but using a low-carbon source like green hydrogen could greatly reduce the emissions from making steel.

Ammonia is made by producing hydrogen from natural gas and then combining it with atmospheric nitrogen. Both the hydrogen production and ammonia synthesis are energy intensive. Using green hydrogen would eliminate emissions from the hydrogen production itself and new research on catalysts aims at lower-temperature, less-energy intensive ammonia synthesis.

Decarbonizing cement manufacturing is perhaps the toughest challenge. Cement is made in a high-temperature kiln, typically heated by burning fossil fuels. The process converts calcium carbonate and clay into a hard solid called clinker. The main byproduct of that is even more carbon dioxide. Burning green hydrogen and capturing carbon emission are about the best hope for reducing cement manufacturing emissions.

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Can the World’s Most Polluting Heavy Industries Decarbonize?

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Earth Wise is a production of WAMC Northeast Public Radio.

Making Coal To Fight Climate Change

April 19, 2019 By EarthWise Leave a Comment

Coal is the most harmful fossil fuel for the environment and, furthermore, for human health. Its use has stubbornly persisted because it is so plentiful and, therefore, cheap. As a result, a big part of efforts to fight climate change is finding a way to remove the carbon dioxide dumped into the atmosphere by the combustion of coal.

Researchers at the Royal Melbourne Institute of Technology in Australia have developed a remarkable technology that in effect reverses the process that has led to soaring CO2 levels in the atmosphere. They have found a way to pull carbon dioxide from the atmosphere and turn it into coal, after which it can be stored cheaply and safely underground.

Most previous carbon capture and storage technologies have focused on compressing carbon dioxide gas into a liquid form and then pumping it into rock formations. Such techniques are rather expensive, require lots of energy, and pose risks that the liquid CO2 could escape from its underground storage sites. More recently, research on solid metal catalysts has led to the possibility of turning CO2 into solid carbon, but most of these reactions require very high temperatures and use a lot of energy.

The new technique developed at RMIT uses a new class of catalysts based on metal alloys. With a small jolt of electricity applied at room temperature, CO2 can be converted into solid carbon – basically, coal.

If this technique can be industrialized economically, it would be like turning back the clock by taking carbon dioxide that entered the atmosphere by the combustion of coal and turning it back into coal and putting it back underground. It seems like excellent environmental justice.

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