NM04.06.06 : MOF-Derived Bimetallic Nitride Nanosheets for Efficient Electrocatalysis Toward Oxygen Evolution Reaction

5:00 PM–7:00 PM Apr 4, 2018 (America - Denver)

PCC North, 300 Level, Exhibit Hall C-E

Su-Ho Cho1 Won-Tae Koo1 Ki Ro Yoon1 Ji-Won Jung1 Doo-Young Youn1 Chanhoon Kim1 Jun-Young Cheong1 Il-Doo Kim1

1, Korea Advanced Institute of Science and Technology, Daejeon, , Korea (the Republic of)

Due to climate change and depletion of fossil fuels, the advanced technologies for clean and renewable energy storage and conversion system, such as fuel cells, water splitting, and metal-air batteries, have become a crucial role in next-generation energy system. Among the next-generation energy systems, the oxygen-related electrochemistry is considered a key reaction. However, the oxygen-related electrochemical reaction, especially oxygen evolution reaction (OER) has sluggish kinetics, due to the complex proton-coupled electron transfer, which hinder the practical implementation for energy conversion systems. Highly active catalyst use is essential to achieve high efficiency for the energy system. Typically, precious metal-based electrocatalysts including iridium and ruthenium oxide are well-known to be efficient for the OER. Though they has highly electrocatalytic activity, their high cost and low durability are pointed out as a limitation. Among the innovative attempts for addressing challenge, transition metal-based electrocatalysts have been proposed to replace the precious metal catalysts, particularly cobalt-based electrocatalysts has high electrocatalytic activity and high stability at high potential for electrocatalysis. In Co-based materials, cobalt nitride (CoxN) has metallic electronic structure with high electrical conductivity, and its high electrocatalytic activity is already reported. Additionally, foreign metal atoms into the original crystal lattice of transitiom metal based materials can increase the electrocatalytic activities of bimetallic materials. Metal organic framework (MOF) is the porous material with remarkably high surface area that allows extensive electrolyte contact and numerous active sites. Due to these advantages, MOF-derived materials are undergoing much research in the electrocatalysis field. In addition, it is possible to develop MOF structure of various composition through the change of metal ion during the synthesis process. Therefore, the electronic structures of MOF-derived materials can be easily tuned through the foreign metal-doped MOF structure. In this work, Co-based MOF (ZIF67) was fabricated using solution synthesis and transformed into a nanosheet structure. The composition of foreign metal atom was controlled by the content of metal precursor in ZIF67 synthesis process. Through ammonia heat treatment, the Co-based bimetallic nitride nanosheets were prepared. The synthesized Co-based bimetallic nitride nanosheet achieved low overptential for the OER in alkaline media (520 mV in 0.1 M KOH), and has a higher current density than the particles at the same potential. Through this work, the bimetallic nitride materials with 2D nanosheet structure can promote their practical use with their remarkable structural and electronic characteristics.