Nearly a century ago, German chemist Fritz Haber won the Nobel Prize in Chemistry for a process to generate ammonia from hydrogen and nitrogen gases. The process, still in use today, ushered in a revolution in agriculture, but now consumes around one percent of the world’s energy to achieve the high pressures and temperatures that drive the chemical reactions to produce ammonia.
Today, University of Utah chemists publish a different method, using enzymes derived from nature, that generates ammonia at room temperature. As a bonus, the reaction generates a small electrical current. The method is published in Angewandte Chemie International Edition.
Although chemistry and materials science and engineering professor Shelley Minteer and postdoctoral scholar Ross Milton have only been able to produce small quantities of ammonia so far, their method could lead to a less energy-intensive source of the ammonia, used worldwide as a vital fertilizer.
“It’s a spontaneous process, so rather than having to put energy in, it’s actually generating its own electricity,” Minteer says.
How to make ammonia
Both the Haber-Bosch process (named also for Carl Bosch, who scaled up the process for industrial production) and the process developed by Minteer and Milton are based on fundamental chemical principles. To make ammonia, which consists of one nitrogen atom and three hydrogen atoms, chemists must break the strong bond that holds two nitrogen atoms together, and then reduce the nitrogen, or add electrons and protons to it in the form of hydrogen. In the Haber-Bosch process, hydrogen and nitrogen gas are pumped over beds of metal catalysts, which aid the reaction, at pressures up to 250 times atmospheric pressure and temperatures up to 500 degrees Celsius (932 F). The process currently produces nearly 500 million tons of ammonia every year.
Simulating a cell
In biology, conversion of gaseous nitrogen to ammonia is called nitrogen “fixation” and is accomplished through several pathways, including through enzymes called nitrogenases. Used by some bacteria, nitrogenases are the only known enzymes to reduce nitrogen to ammonia. Nitrogenase is rarely studied in fuel cell applications, because the enzyme is not commercially available and must be handled in an oxygen-free environment.
“One of the things my group does well is designing the interface between the enzyme and the electrode, so the enzymes can communicate with electrode surfaces,” Minteer says.
Minteer and Milton envisioned a fuel cell system that replicated the biological process of nitrogen fixation, using nitrogenase and hydrogenase, an enzyme graciously provided by Minteer’s collaborators at the Instituto de Catalisis y Petroleoquimica in Spain, to strip electrons from hydrogen gas and provide them to the nitrogen-reducing reaction.
The cell consists of two compartments, connected via carbon paper electrodes. In one vial, hydrogen gas is oxidized by hydrogenase and electrons are carried to the anode. In the other, electrons come off the cathode and are combined with nitrogen, via nitrogenase, to create ammonia.
The electrons move from the anode to the cathode via a circuit. Protons (oxidized hydrogen atoms) travel through a membrane between the anodic and cathodic chambers, supplying the hydrogen atoms needed to synthesize ammonia.
The movement of the electrons creates current, and is the source of the small amount of electrical power generated by the reaction.
Several challenges remain to be overcome before Minteer and Milton’s small-scale process can find application at an industrial scale. One is the oxygen sensitivity of nitrogenase, another is the requirement of chemically-expensive ATP, a source of energy in cells and in nitrogen fixation. Milton says that re-engineering the reaction to circumvent the need for ATP would take the fuel cell “to the next level.” Until then, he says, the most notable and impactful aspect of this work is the production of ammonia without the massive energy drain characteristic of the industry standard process.
“The real thing is not the quantity of ammonia produced, but that it’s possible to make electricity at the same time,” Milton says.
Find the full study here.
Learn more: FLIPPING THE SWITCH ON AMMONIA PRODUCTION
[osd_subscribe categories=’ammonia-production’ placeholder=’Email Address’ button_text=’Subscribe Now for any new posts on the topic “AMMONIA PRODUCTION”‘]
Receive an email update when we add a new AMMONIA PRODUCTION article.
The Latest on: Ammonia production
[google_news title=”” keyword=”ammonia production” num_posts=”10″ blurb_length=”0″ show_thumb=”left”]
via Google News
The Latest on: Ammonia production
- Ammonia Market Size to grow by 38.15 million tons from 2022 to 2027: Increasing demand for fertilizers to boost the market growth - Technavioon June 1, 2023 at 8:15 am
The ammonia (NH3) market size is expected to grow at a CAGR of 3.56% from 2022 to 2027. Market size is expected to increase by 38.15 million tons. One of the main drivers of the NH3 ...
- Japan embracing ammonia power to achieve 2050 zero CO2 targeton May 31, 2023 at 5:01 pm
The council drew up a scenario where ammonia production plants would be built in places suitable for such processes, such as North America and Australia, and supply chains for Japan would be ...
- Pembina Pipeline partnering with Marubeni Corp. on ammonia export projecton May 30, 2023 at 10:58 am
Pembina Pipeline Corp. says it has reached an agreement with Japanese conglomerate Marubeni Corp. to create an ammonia supply chain for exports to Asian markets.
- Pembina, Marubeni sign MoU to develop low-carbon ammonia projecton May 30, 2023 at 6:35 am
Pembina Pipeline (NYSE:PBA) said Tuesday it signed a memorandum of understanding with Marubeni to jointly develop a low-carbon hydrogen and ammonia production facility adjacent to its Redwater complex ...
- Govt Waives Inter-State Transmission Charges For Offshore Wind, Hydrogen, Ammonia Projects For 25 Years – Detailson May 29, 2023 at 10:33 am
In a major decision, the Central Government on Monday decided to grant a waiver of the inter-state transmission system (ISTS) charges to off-shore wind Projects and extend the waiver to Green Hydrogen ...
- Could ammonia help tackle climate change in Europe?on May 29, 2023 at 6:12 am
and aero-engine production. Now, IHI’s Ammonia Value Chain Project is on a mission to provide solutions for carbon neutrality through the global application of “green ammonia” in sectors such as ...
- Keppel to jointly develop green hydrogen, ammonia production facilities in Australiaon May 26, 2023 at 10:58 am
It also inked a memorandum of understanding (MOU) with Incitec Pivot, Australia’s top fertiliser maker, to explore the development of a green ammonia production facility in Gladstone city in ...
- Singapore's Keppel signs deals to ramp up green hydrogen, ammonia outputon May 25, 2023 at 8:37 pm
May 26 (Reuters) - Singapore's Keppel Corp (KPLM.SI) said on Friday it has signed two deals to intensify its efforts in the development of green hydrogen and ammonia production for use in ...
- Japan Wants To Decarbonize With The Help Of Ammoniaon May 23, 2023 at 5:00 pm
In fact, ammonia production currently makes up about 1% of global carbon emissions. Green ammonia is the solution, where the hydrogen is instead supplied in a cleaner fashion. This typically ...
via Bing News