A technology has been developed to easily produce clean gaseous feedstocks like green hydrogen. This technology, which increases the efficiency of raw material production by coating the surface with a thin film, is expected to accelerate the commercialization of green hydrogen production.

A research team led by Professors Ryu Jeong-gi and Lee Dong-wook of the Department of Energy and Chemical Engineering at UNIST (President Lee Yong-hoon) announced on the 24th that they have developed a large-area hydrogel thin film technology that can be universally used in gas-producing electrodes.

This technology, which creates a thin film using hydrogel, a raw material for cosmetics, 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 hovering around 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 produces green hydrogen and oxygen by decomposing water.

When electrical energy flows through an electrochemical reaction, such as water electrolysis, gases such as hydrogen, oxygen, and nitrogen are produced. As these gases are produced, they adhere 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 surface of the electrode was coated with a hydrogel with open 'pores' where gas exchange occurs.

The hydrogel used by the research team is a material currently being mass-produced domestically. Its hydrophilic properties allow it to absorb water, making it widely used in cosmetics, ointments, diapers, and other products. The hydrophilic hydrogel coating allows the gas bubbles generated at the electrode to be immediately removed, allowing the electrolyte to quickly permeate 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).

Additionally, when the gas falls in small sizes rather than accumulating on the surface, the force exerted on the catalyst surface is reduced. This reduces the degree of catalyst clumping or peeling, allowing the electrolysis system to operate stably for extended periods of 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 is especially applicable to water electrolysis reactions, so it will be helpful in commercializing green hydrogen.”

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

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