The advancement of water electrolysis technologies is critical to achieving the green independence of fossil fuels. It is necessary to improve the cost-effectiveness, energy efficiency, and durability of water electrolysis systems. Korean researchers at Incheon National University, Kyung Hee University, and Seoul National University have developed an electrode structure based on a Nitrogen-doped (N-doped) carbon matrix that can promote the performance of polymer electrolyte membrane water electrolysis (PEMWE). This study appeared in the Advanced Functional Materials in March 2023. 

The durability of PEMWE suffers from the corrosion of materials used in the anode side where oxygen evolution reaction (OER) takes place. Highly-oxidative environments easily cause the corrosion of carbon porous transport layers (PTLs). As a result, titanium (Ti) felts, instead of carbon papers, have been used as a PTL in the anode side of PEMWE. However, a relatively small surface area and low conductivity of Ti felts limit the performance of PEMWE. This research team, led by Prof. Oh Joong Kwon, adopted the N-doped carbon matrix to overcome the current limitations. Furthermore, a single-step pyrolysis process has been invented for simultaneously fabricating both cracked N-doped carbon matrix and uniform Ir-Ru nanocatalysts.

The cracked N-doped carbon matrix has better corrosion resistance than the carbon paper, higher electrical conductivity, and a larger surface area compared to Ti felts. The cracked nature of the carbon matrix facilitates the transport of electrolytes and produced gases. Furthermore, the Ir-Ru nanoparticles are protected by thin carbon shells which is simultaneously formed during the pyrolysis process. Due to these advantages of the carbon matrix, the performance of water electrolysis surpasses that from commercial electrocatalysts and Ti felts. 

Prof. Kwon said that "We have proved that the stability of the electrode based on the N-doped carbon is sufficient enough for tolerating oxidative conditions at the anode side of PEMWE. The novel cracked structure and material characteristics of N-doped carbon matrix can be applied for other electrochemical systems dealing with gaseous reactants and products, such as CO2 electrochemical reduction."

Ir-Ru nanocatalysts and cracked N-doped carbon matrix fabricated via a single pyrolysis process

[Reference] T.B. Ngoc Huynh et al., “Ir-Ru Electrocatalysts Embedded in N-Doped Carbon Matrix for Proton Exchange Membrane Water Electrolysis”, Advanced Functional Materials, 2023, DOI: 10.1002/adfm.202301999

[Main Author] T.B. Ngoc Huynh, Oh Joong Kwon (Incheon National University), Myung Jun Kim (Kyung Hee University), Yung-Eun Sung (Seoul National University)

* Contact email : Professor Oh Joong Kwon (ojkwon@inu.ac.kr)