Sandwich catalysts offer higher activity and durability

Date:
August 26, 2020
Source:
Pohang University of Science & Technology (POSTECH)
Summary:
A professor has developed a double-layered nanoporous platinum
catalyst that activates hydrogen generation.



FULL STORY ========================================================================== Sandwich is the food concocted by the 18th-ceuntry nobles to play card
games uninterrupted. Meat or vegetables were layered then tucked between
bread to be eaten quickly while engaged in the game. This efficient food
also delivered ample calories and nutrition. POSTECH research team has discovered that layering like the sandwich is an excellent way to obtain hydrogen energy, an alternative energy source for fossil fuels.


==========================================================================
The research team led by Professor In Su Lee, SunWoo Jang, a student in
the MS/ PhD integrated program, and Dr. Soumen Dutta of the Department
of Chemistry at POSTECH have together developed a sandwich structured
catalyst that can efficiently generate hydrogen energy by activating
water electrolysis. The research findings were recently published in
the American Chemical Society's international journal ACS Nano.

Hydrogen fuel cells are eco-friendly power-generating devices that
generate electricity using chemical reactions that produce water
(H2O) from oxygen (O2) and hydrogen (H2). With the recent release
of hydrogen-powered vehicles and the spread of hydrogen fuel cells
in households, hydrogen is widely seen as the next-generation energy
source to replace fossil fuels. The way water is decomposed and hydrogen
is produced using surplus current obtained from solar or wind power is considered the easiest and most eco-friendly way to produce high purity hydrogen fuel in large quantities. However, this method has a disadvantage
of being low in production efficiency and high in cost. In order to lower
the unit price of hydrogen fuel produced through water electrolysis,
it is necessary to develop highly active and stable electrochemical
catalysts that can maximize hydrogen generation efficiency.

Platinum (Pt) has been considered the most suitable catalyst for hydrogen- producing reactions, but its low affinity for water molecules and the
resulting slow rate of water electrolysis make it difficult to apply
to commercial processes that take place under alkaline electrolyte
conditions. To make up for these limitations, many attempts have been
made to combine metal-sulfide with platinum nanoparticles that promote
water electrolysis, but the unstable nature of platinum/metallic-sulfide surfaces poses another weakness that significantly reduces the durability
of catalysts.

In response, the research team designed a two-dimensional form
of platinum/ metal-hydroxide interface to improve the efficiency
and durability of catalysts at the same time. In an original
technique to grow a platinum layer of about 1 nm on the surface of nickel/iron-double-hydroxide(LDH), which is several nanometers thick,
2D-2D nanohybrid materials in the form of sandwiches containing 2D-nickel/iron-hydroxide-nano plates have been successfully synthesized.

The synthesized sandwich catalyst has a synergistic catalytic effect
between metal-hydroxide and platinum, which are in close contact
across a wide 2D-2D interface. At this time, it shows more than 6
times the activity of the conventional catalytic material (20%-Pt/C),
and maintains stable catalytic function without decreasing activity even
in the hydrogen-producing water electrolysis for more than 50 hours.

"Sandwich catalysts have the highest alkali solution hydrogen-producing catalytic activity among substances that do not use carbon supports, but
are significantly more durable than similar electrochemical catalysts
that are stable for just three to five hours," said Professor In Su
Lee who led the research. "We expect them to be applied to developing
a cost-effective process for hydrogen production." This research was
conducted with the support from the Research Leader Program (Creative
research) of the National Research Foundation of Korea.


========================================================================== Story Source: Materials provided by Pohang_University_of_Science_&_Technology_(POSTECH).

Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Sun Woo Jang, Soumen Dutta, Amit Kumar, Yu-Rim Hong, Hanuel Kang,
Shinbi
Lee, Sunmin Ryu, Wonyong Choi, In Su Lee. Holey Pt Nanosheets on
NiFe- Hydroxide Laminates: Synergistically Enhanced Electrocatalytic
2D Interface toward Hydrogen Evolution Reaction. ACS Nano, 2020;
14 (8): 10578 DOI: 10.1021/acsnano.0c04628 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200826101633.htm

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