Japanese researchers find a safe, easy, and affordable way to store and retrieve hydrogen that “can be a part of the solution for achieving a decarbonized society through the use of ammonia as carbon-free hydrogen carrier.”
Scientists at the RIKEN Center for Emergent Matter Science (CEMS) in Japan have made a groundbreaking breakthrough, uncovering a Perovskite (EAPbI3) that enables the safe and convenient storage of ammonia, along with the crucial hydrogen it carries. This discovery paves the way for a practical hydrogen economy, offering a significant step towards a decarbonized society.
A team of scientists from the RIKEN Center for Emergent Matter Science (CEMS) has made a remarkable breakthrough by discovering a compound that revolutionizes the storage and retrieval of hydrogen. By leveraging a chemical reaction, this groundbreaking method offers a safe, easy, and affordable way to store ammonia—a key hydrogen carrier. With implications for a decarbonized society and a practical hydrogen economy, this discovery holds immense potential.
An innovative solution for the safe, convenient, and cost-effective storage and retrieval of hydrogen has been uncovered by scientists at the RIKEN Center for Emergent Matter Science (CEMS) in Japan.
Their groundbreaking discovery, published in the Journal of the American Chemical Society on July 10, introduces a compound that utilizes a chemical reaction to store ammonia, providing a potential breakthrough in ammonia and hydrogen storage.
This advancement paves the way for a practical hydrogen-based economy, contributing to the realization of a decarbonized society.
Transitioning from carbon-based to hydrogen-based energy requires a secure means of storing and transporting hydrogen, a highly combustible substance on its own. One viable strategy involves storing hydrogen within another molecule and extracting it as needed. Ammonia, represented chemically as NH3, serves as an excellent hydrogen carrier since each molecule contains three hydrogen atoms, making up nearly 20% of its weight.
However, ammonia presents challenges due to its highly corrosive nature, making storage and usage difficult. Currently, ammonia is primarily stored by liquefying it at temperatures well below freezing in containers built to withstand high pressure. While porous materials can store ammonia at room temperature and atmospheric pressure, their storage capacity is limited, and retrieving the ammonia can be cumbersome. The recent study details the discovery of a perovskite—a material with a distinct repetitive crystal structure—that not only facilitates easy ammonia storage but also allows for its complete retrieval at relatively low temperatures.
Under the guidance of Masuki Kawamoto, the research team at RIKEN CEMS focused on a perovskite called ethylammonium lead iodide (EAPbI3), denoted chemically as CH3CH2NH3PbI3. They observed that its one-dimensional columnar structure undergoes a chemical reaction with ammonia at room temperature and pressure, transforming dynamically into a two-dimensional layered structure known as lead iodide hydroxide, or Pb(OH)I. As a result, ammonia becomes stored within this layered structure through chemical conversion.
Consequently, EAPbI3 offers a safe and affordable alternative to storing corrosive ammonia gas, surpassing the need for expensive liquefaction processes at -33°C (-27.4°F) and high-pressure containers. Equally important, the retrieval process for the stored ammonia is straightforward.
“To our surprise, ammonia stored in ethylammonium lead iodide could be easily extracted by heating it gently,” explains Kawamoto.
The stored nitrogen compound undergoes a reverse reaction at a temperature as low as 50°C (122°F) under vacuum conditions, converting back to ammonia. This temperature requirement is significantly lower than the 150°C (302°F) typically needed to extract ammonia from porous materials. Consequently, EAPbI3 serves as an outstanding medium for handling corrosive gases in a simple and cost-effective manner, according to the author.
Furthermore, once the perovskite reverts to its original one-dimensional columnar structure, it can be reused, allowing for repeated storage and extraction of ammonia. An additional advantage is the color change observed in the compound, turning from yellow to white following the reaction.
Kawamoto adds, “the compound’s ability to change color when storing ammonia means that color-based ammonia sensors can be developed to determine the amount of ammonia stored.”
This novel storage method exhibits numerous practical applications. In the short term, the researchers have developed a safe technique for storing ammonia, a chemical already utilized in various societal domains, including fertilizers, pharmaceuticals, and textiles.
Looking ahead, Yoshihiro Ito, a co-author from RIKEN CEMS, expresses hope “that this simple and efficient method can be a part of the solution for achieving a decarbonized society through the use of ammonia as carbon-free hydrogen carrier.”
Source: 10.1021/jacs.3c04181
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