With this approach, the developed photocathodes exhibit remarkable stability and demonstrate sunlight-driven production of clean hydrogen through water splitting
GWANGJU, South Korea, September 23, 2022 /PRNewswire/ — Hydrogen is emerging as a popular green alternative to fossil fuels due to its carbon-neutral combustion products (water, electricity and heat) and is being considered the next-generation zero-emission fuel for society. Ironically, however, the main source of hydrogen is fossil fuels.
One way to produce hydrogen in a clean and sustainable way is through sunlight-powered water splitting. The process known as “photoelectrochemical (PEC) water splitting” is the basis for the operation of organic photovoltaic cells. What makes this method attractive is that it allows 1) the mass production of hydrogen in a limited space without a grid system and 2) the highly efficient conversion of solar energy into hydrogen. However, despite these advantages, the photoactive materials used in conventional PECs do not have the properties required for commercial application. In this regard, organic semiconductors (OSs) have emerged as a potential photoelectrode material for commercial PEC hydrogen production due to their high performance and low-cost printing. On the other hand, however, OSs suffer from poor chemical stability and low photocurrent density.
Now a research team led by Prof. Sangan Lee from the Gwangju Institute of Science and Technology, Korea, may have finally solved this problem. In her recent breakthrough, which made the front page of the Journal of Materials Chemistry Athe team followed an approach based on encapsulating the OS photocathode in platinum-decorated titanium foil, a technique known as “metal foil encapsulation,” to prevent it from being exposed to the electrolyte solution.
“Metal foil encapsulation is a powerful approach to realizing long-term stable OS-based photocathodes as it helps prevent electrolytes from penetrating the OS, Improving their long-term stability, as shown in our previous studies and other reports on OS-based photoelectrodes,“, explains Prof. Lee. The study was made available online May 14, 2022 and was published in issue #25 of the magazine July 07, 2022.
The team fabricated an organic photovoltaic cell in which the OS photocathode was covered with titanium foil and well-dispersed platinum nanoparticles. When tested, the OS photocathode showed an initial potential of 1 V versus the reversible hydrogen electrode (RHE) and a photocurrent density of -12.3 mA cm-2 at 0VRHE. Most notably, the cell showed record operational stability, maintaining 95.4% of maximum photocurrent over 30 hours with no noticeable OS degradation. The team also tested the module under real sunlight and was able to produce hydrogen.
The highly stable and efficient PEC module developed in this study can enable large-scale production of hydrogen and inspire innovative ways to build future hydrogen fueling stations. “With the growing threat of global warming, it is imperative to develop environmentally friendly energy sources. The PEC module examined in our study could be installed in hydrogen fueling stations, where hydrogen can be mass-produced and sold simultaneously,“, speculates an optimistic Prof. Lee.
We really hope that his vision will be realized soon!
Original work title: A long-term stable organic semiconductor photocathode-based photoelectrochemical module system for hydrogen production
Diary: Journal of Materials Chemistry A
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Chang Sung Kang
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