(6ej) Energy Conversion and Storage

The depleting fossil fuels unprecedentedly motivate the development of new energy technologies, nowadays. It is highly desirable to produce energy from renewable sources, to storage energy and then to work efficiently and cleanly. To implement the new energy system at a large scale, the new energy technologies must be competitive with current fossil fuel energy system. With this requirement in mind, Kang Group focuses on the fundamental understanding of catalytic processes that are involved in energy conversion and storage. We address the challenge through a three-step-approach: we first investigate the structure-property correlation on a well-defined surface (e.g. single crystal); second, we construct highly controlled nano-scale model materials to verify the validity of structure-property correlation that is observed on well-defined systems; and finally we implement the knowledge learned from our well-defined and nano-sized models into the real word – to produce the catalytic materials that are potentially usable in industry. Currently, our research interests cover following topics:

• Hydrogen economy.

The so-called “hydrogen economy” is a proposed new energy system in which the hydrogen is the energy carrier. The hydrogen comes from the renewable energy powered hydrogen production which is ideally water splitting. The hydrogen is consumed by the end-users through a device called fuel cell. We are closely working on the catalytic processes associated with the hydrogen economy, including hydrogen oxidation reaction (HOR), oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), and oxygen evolution reaction (OER).

Representative publications:

1. Huang, L.L.; Chen, P.; Liu, M.H.; Fu, X.B.; Gordiichuk, P.; Yu, Y.N.; Wolverton, C.; Kang, Y.J.*; Mirkin, C.A.* Catalyst design by scanning probe block copolymer lithography Natl. Acad. Sci. USA, 2018, 115 (15), 3764-3769
2. Qu, G.X.; Zhou, Y.; Wu, T.; Zhao, G.; Li, F.; Kang, Y.J*.; Xu, C.* Phosphorized MXene-phase Molybdenum Carbide as Earth-Abundant Hydrogen Evolution Electrocatalyst ACS Appl. Energy Mater. 2018, 1 (12), 7206-7212
3. Kang, Y.J.; Yang P.D.; Markovic, N.M.; Stamenkovic, V.R. Shaping electrocatalysis through tailored nanomaterials Nano Today, 2016, 11 (5), 587-600
4. Chen, C.†; Kang, Y.J.†( †co-first authors); Huo, Z.; Zhu, Z.; Huang, W.Y.; Xin, H.L.; Snyder, J.D.; Li, D.G.; Herron, J.A.; Mavrikakis, M.; Chi, M.F.; More, K.L.; Li, Y.D.; Markovic, N.M.; Somorjai, G.A.; Yang, P.D.; Stamenkovic, V.R. Highly Crystalline Multimetallic Nanoframes with Three-Dimensional Electrocatalytic Surfaces Science, 2014, 343 (6177), 1339

• Chemical upgrade of environment-abundant small molecules.

While the renewable energy sources may solve the global energy problem, it is unable to directly provide chemical products that are currently from petro-industry. Our solution is to chemically upgrade the small molecules that are abundant in our environment, including CO and CO₂.

Representative publication:

1. Luc, W.; Fu, X.B.; Shi, J.J.; Lv, J.J.; Jouny, M.; Ko, B.H.; Xu, Y.B.; Tu, Q.; Hu, X.B.; Wu, J.S.; Yue, Q.; Liu, Y.Y.; Jiao, F.*; Kang, Y.J.* Two-Dimensional Copper Nanosheets for Electrochemical Reduction of Carbon Monoxide to Acetate Nature Catal., 2019, 2, 423-430 (cover featured)

• Nitrogen reduction for ammonia synthesis.

Ammonia is a key chemical for our industries and daily life, however, the ammonia synthesis is a high energy consumption industry and environment-unfriendly. Nitrogen reduction (NRR) to produce ammonia attracts great attention recently, however, the reported ammonia production rate (~10^-8 mol cm^-2 h^-1, usually) is not even close to any practical application. Our recent revolutionary result increases the ammonia production rate by 3-4 orders of magnitude (to be published), making NRR a promising route for ammonia production. In the other hand, we are also pursuing the alternative route other than NRR to convert N₂ in the air to ammonia.

• Energy storage

Among many new technologies toward energy storage, Kang Group focuses on Li metal batteries and Li-S batteries for their high theoretic capacity and foreseeable future.

Representative publications:

1. Xu, Y.; Li, T.; Wang, L.P.; Kang, Y.J.* Interlayered Dendrite-free Lithium Plating for High-performance Lithium Metal Batteries Adv. Mater., 2019 doi.org/10.1002/adma.201901662
2. Xu, Y.; Wang, L.P.; Jia, W.; Yu, Y.N.; Zhang, R.Y.; Li, T.; Fu, X.B.; Niu, X.B.; Li, J.Z.*; Kang, Y.J.* Three-dimensional carbon material as stable host for dendrite-free lithium metal anodes Electrochimica Acta, 2019 301, 251-257

Teaching Interests:

Any subject that is related to energy conversion and storage, including but not limited to: transport, thermodynamics, reaction and reaction engineering, catalysis, materials science and engineering, materials chemisty and etc.