A technology has been developed that can easily produce clean gaseous raw materials such as green hydrogen. This technology, which increases the efficiency of raw material production by coating a thin film on the surface, is expected to accelerate the commercialization of green hydrogen production.

UNIST (President Yong-Hoon Lee) Department of Energy and Chemical Engineering Professor Jeong-Ki Ryu and Professor Dong-Wook Lee's team announced on the 24th that they have developed a large-area hydrogel thin film technology that can be used universally for gas producing electrodes.

This technology, which creates a thin film using hydrogels used as cosmetic raw materials, dramatically increases the production efficiency of gaseous raw materials produced by applying electricity to electrodes.

This helps the gaseous raw material to escape easily without lingering on the outside of the electrode.

In particular, it is expected to take the lead in achieving carbon neutrality as it can be applied to water electrolysis technology that decomposes water to produce green hydrogen and oxygen.

When electrical energy flows through an electrochemical reaction such as electrolysis, gases such as hydrogen, oxygen, and nitrogen are generated. As the gases are generated, they attach to the surface of the electrode in the form of air bubbles. Among the gases produced in this way, 'hydrogen' is an important resource for industry, but it is considered a factor that increases energy consumption by interfering with the permeation or action of electrolytes.

The research team studied a method to quickly remove gas bubbles from the surface of the electrode and efficiently supply electrolyte.

First, the outer surface of the electrode was coated with a hydrogel with open 'pores' through which gas exchange occurs.

The hydrogel used by the research team is a material that is being mass-produced domestically and has hydrophilic properties that absorb water, so it is widely used in cosmetics, ointments, diapers, etc. When the gas bubbles generated on the electrode are removed immediately through the hydrophilic hydrogel coating, the electrolyte quickly permeates the electrode without being disturbed by the gas.

The research team applied the system they developed to existing nickel and platinum catalysts, and showed a gas production efficiency that was up to 2.3 times higher (65.7 mA/cm2 -> 151.5 mA/cm2).

In addition, if the gas falls in a small size without accumulating on the surface, the force applied to the catalyst surface is reduced. This reduces the degree of catalyst agglomeration or peeling, allowing the electrolysis system to operate stably for a long time.

Professor Ryu Jeong-gi of the Department of Energy and Chemical Engineering said, “This is a creative original technology that significantly improves the efficiency of electrochemical gas production reactions by applying hydrogels, which are widely used in daily life such as wet bandages, cosmetics, and diapers, to electrodes.” He also expressed his expectations, saying, “It can especially be applied to water electrolysis reactions, so it will be helpful in commercializing green hydrogen.”

This study was participated by Yunseok Kang, a combined master's and doctoral student in the Department of Energy and Chemical Engineering at UNIST, as the first author. The research results were published on September 29 in 'Advanced Functional Materials,' an internationally authoritative journal in the field of electrochemistry.

This study was conducted with the support of the Mid-career Researcher Support Project, Climate Change Response Technology Development Project, and Regional Innovation Leading Research Center (RLRC) Project of the National Research Foundation of Korea, Ministry of Science and ICT.