Joo, Sang Hoon

Joo, Sang Hoon

Joo, Sang Hoon 주상훈
Materials Chemistry

Sang Hoon Joo completed undergraduate in chemistry at KAIST (B.S. 1998). He continued his graduate studies in materials chemistry at KAIST with Prof. Ryong Ryoo (M.S. 2000; Ph.D. 2004), focusing on the synthesis and catalytic applications of ordered mesoporous carbons. After an industrial experience as a Research Staff Member at Samsung Advanced Institute of Technology (2004-2007), he moved to UC Berkeley for his postdoctoral studies with Prof. Gabor Somorjai investigating colloidal nanoparticle based nanocatalysts (2007-2009). He joined the UNIST faculty in 2010 and was promoted to an Associate Professor in 2014 and a Professor in 2019, and he is currently a Professor of Chemistry. An author of over 160 publications that have been cited over 20,000 times with an h-index of 56, he received TJ Park Junior Faculty Fellowship, the Knowledge Creation Award, the KCS Award in Materials Chemistry among other honors, is a member of Young Korean Academy of Science and Technology (Y-KAST), and currently holds UNIST Young Distinguished Professorship.
Research Summary
The coupled challenges of a doubling in the world’s energy needs by the year 2050 and the ever-increasing demands for “clean” energy sources have brought increasing attention worldwide to the possibility of a “hydrogen economy” as a long-term solution for securing energy future. While the hydrogen economy offers a compelling vision of an energy future for the world, significant scientific and technical challenges should be addressed to achieve its implementation. The key components for the hydrogen-based energy cycle are integrated electrochemical energy devices such as fuel cells, water electrolyzers, and solar fuel systems. The performance of these energy conversion devices depends critically on the efficiency and durability/stability of catalysts for electrochemical reactions at the electrodes of these devices. The reactions include the electrocatalytic hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR) of a hydrogen fuel cell, and the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) of a water electrolyzer. These reactions involve multi-electron transfers and are kinetically demanding. Hence, precious metal-based materials such as Pt, Ru, or Ir with high reaction kinetics have been prevalent choice of catalysts. However, the prohibitively high cost and scarcity of precious metal-based catalysts combined with declining activity during long-term operation have impeded the widespread use of fuel cells and water electrolyzers. Hence, the development of economic electrocatalysts with high activity and durability/stability has been of utmost importance in this area of research.

Combining solid-state materials chemistry, electrochemistry, and catalysis, Prof. Joo’s group has endeavored to (i) develop highly active, stable, and cost-effective electrocatalysts for renewable energy conversion reactions, (ii) identify the activity descriptor and active sites of catalysts by exploiting in situ spectroscopic methods in combination with theoretical calculations, and (iii) translate the newly developed catalysts into system-level devices. Ultimate goal of our research is to establish the catalyst structure-activity relationship, which in turn help design next-generation catalysts for renewable energy conversion reactions.

저희 연구실에서는 화석연료가 야기하는 지속적인 지구 온난화 문제와 가파르게 증가하는 전지구적인 에너지 수요에 대응할 수 있는 소위 “수소경제 (hydrogen economy)”를 위한 에너지 사이클 (energy cycle)을 구현할 수 있는 연구를 수행합니다. 수소 기반 에너지 사이클을 성공적으로 완성할 수 있는 핵심 기술은 연료전지 및 수전해 장치와 같은 에너지 변환 장치의 효율이며, 이는 각 전극의 촉매의 성능과 내구성에 좌우됩니다. 현재 이러한 장치의 전극 촉매로는 백금, 이리듐, 루테늄 기반의 귀금속 촉매가 주로 사용됩니다. 하지만 이러한 물질은 가격이 매우 비싸고, 매장량이 한정되어 있으며, 쉽게 피독이 되며, 내구성이 떨어지는 단점이 있습니다. 따라서, 에너지 변환 장치의 폭넓은 상용화를 위해서는 지각풍부 원소 기반의 저가 촉매로 높은 성능과 내구성을 구현하는 것이 매우 중요합니다.

저희 연구실에서는 재료화학, 전기화학, 그리고 촉매 분야 연구를 융합하는 접근법을 이용하여 (i) 연료전지와 수전해 장치의 전극 반응들인 산소환원반응 (ORR), 산소발생반응 (OER) 및 수소발생반응 (HER)을 위한 저가, 고성능, 고내구성 촉매 개발, (ii) 실시간 분광법과 이론 계산을 이용한 촉매 활성을 지배하는 인자 및 촉매 활성점 확인, 그리고 (iii) 새롭게 개발한 촉매의 시스템 수준 디바이스 적용에 관해 연구합니다. 저희 연구의 궁극적인 목적은 촉매 구조와 활성간의 상관관계를 확립하여 신재생 에너지 변환을 위한 차세대 촉매를 설계하는 것입니다.

Representative Publications
Atomically Dispersed Pt−N4 Sites as Efficient and Selective Electrocatalysts for the Chlorine Evolution Reaction
Nature Commun., 2020, 11, 412.
Unassisted Solar Lignin Valorisation Using a Compartmented Photo-Electro-Biochemical Cell
Nature Commun., 2019, 10, 5123.
Active Edge-Site-Rich Carbon Nanocatalysts with Enhanced Electron Transfer for Efficient Electrochemical Hydrogen Peroxide Production
Angew. Chem. Int. Ed., 2019, 58, 1100.
Oxygen-Deficient Triple Perovskites as Highly Active and Durable Bifunctional Electrocatalysts for Oxygen Electrode Reactions
Science Advances, 2018, 4, eaap9360.
A General Approach to Preferential Formation of Active Fe–Nx Sites in Fe–N/C Electrocatalysts for Efficient Oxygen Reduction Reaction
J. Am. Chem. Soc., 2016, 138, 15046.
Intrinsic Relationship between Enhanced Oxygen Reduction Reaction Activity and Nanoscale Work Function of Doped Carbons
J. Am. Chem. Soc., 2014, 136, 8875.