This technology is a process for synthesizing low-dimensional hyperthin iron disulfide (FeS2) nanostructures to be used as electrocatalysts for hydrogen production through water-splitting reactions.
Hydrogen rarely occurs naturally as a gas on Earth, yet it is extremely useful in a variety of chemical and industrial processes, as well as in energy generation (mainly in fuel cells that provide pollution-free electric power). Thus, the world produces over 250 billion cubic meters of it each year, primarily through the reformation of natural gas. This process relies on nonrenewable resources and results in significant greenhouse gas emissions. Hence, more advanced processes to produce hydrogen economically from sustainable resources are needed.
The most promising solution is to make use of the water-splitting reactions, i.e., the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), to produce hydrogen from water and electricity. Currently, this is not an economically viable solution, as it requires the use of precious metals (e.g., platinum) as electrocatalysts. A key green energy initiative is the discovery of efficient, stable, and Earth-abundant electrocatalysts for water splitting. This would provide a pathway to use water (as opposed to natural gas) as a feedstock for hydrogen production. The KU invention provides a simple and inexpensive method for producing such a catalyst.
This technology is useful for the cost-effective production of hydrogen from water. It could be employed on an industrial scale or for point-of-use production.
Using an easy and inexpensive solution processing method, the FeS2 catalyst can be synthesized with different nano-morphologies (1D nano-wires and 2D nano-discs) by adjusting the initial sulfur concentration.The nano-disc structure is approximately 100-200 nm wide (about 1000 times smaller than the width of a human hair) and only about 5 nm thick (about 1000 times smaller than a single human red blood cell). Experiments have shown that this structure has particularly good electrochemical activity – similar to platinum – and is stable in neutral pH conditions.
The KU innovation enables economical production of hydrogen without requiring rare and expensive noble metals as catalysts. Lowering the cost of hydrogen production will increase adoption of sustainable energy sources and allow point-of-use production to eliminate storage and transportation dangers.
Previous methods for producing iron sulfides with atomic layer thickness have relied on chemical vapor deposition
(CVD), electrodeposition, techniques requiring high temperature sulfurization, and/or a brute force cleavage. This method utilizes a solution hot-injection method, analogous to a previously reported iron sulfide synthesis, to create unique hyperthin iron sulfide nanostructures with atomic layer thickness.