LEE, Jim Yang
 

Professor and Head
 

PhD (Chem. Eng.) Mich., 1985
MSE (Chem. Eng.) Mich., 1980
BSc (Chem. Eng.) Sing., 1979
 

Contact information
Blk E5, 4 Engineering Drive 4, #02-11, Singapore 117576
Tel: (65) 6516 2186   Fax: (65) 6779 1936
Email: chehead@nus.edu.sg (business)
          cheleejy@nus.edu.sg (personal)

Adjunct Principal Scientist, Institute of Materials Research and Engineering
Fellow, Singapore-MIT Alliance

RESEARCH

Synthesis and applications of nanomaterials

Our current interest in this area is core-shell nanoparticles whereby the physical properties of the core component may be combined with the chemical properties of the shell component to advantage. We have developed phase-transfer methods for the visual detection of the core-shell architecture, and for size-sorting of nanoparticles. We use a wide range of preparation methods from microwave, sonochemical, molten salts and ionic liquids, to various soft and hard templates. A biologically inspired synthesis of gold nanoaprticles with very high yield of triangular gold nanoparticles was recently accomplished.

The molecular recognition properties of biomolecules are being used to form interesting nanostructures. We have used short, single stranded DNA to guide the assembly of Pt and Ru nanoparticles, for the purpose of elucidating the difference between nanoalloys and an intimate mixture of nanoparticles in catalysis. We have discovered very strong interaction between small metal nanoparticles and DNA which may have significant health and environmental consequences on the use of nanomaterials.

Materials for batteries and fuel cells

We are interested in modifying the lithium ion battery anode to increase the energy density of the cell. Our strategy is to compound graphite with high capacity lithium storage compounds (e.g. Sn and Si) at the nanoscale to increase the anode capacity without losing the graphite cyclability. The nanocomposites are formed with particular attention to the composition, size and morphology control of the Sn-containing phase. Various methods have been used but a particularly interesting nanostructure that cycled well was carbon-SnO2 core-shell nanotubes which we have produced by growing SnO2 and carbon nanotubes successively in the pores of anodic aluminum oxide membranes.

Our work on fuel cells is focused on direct methanol fuel cells (DMFC) where methanol is catalytically oxidized at room temperature for the direct generation of electrical energy. The major challenges in DMFC are inadequate electrode kinetics, catalyst deactivation and methanol crossover from the fuel electrode to the air electrode. We are developing nanostructured (e.g. core-shell) anode and cathode catalysts, and methanol-blocking proton-conducting polymer electrolyte membranes as concurrent solutions to these problems. We have enhanced the Pt anode kinetics by using carbon nanotubes as the catalyst support, and discovered Pd to be more fuel-tolerant than Pt at the cathode. We have also developed an embedded polymerization scheme (with Prof. L. Hong) to form tri-layered polymer electrolyte membranes that have good methanol-blocking characteristics, good mechanical properties and satisfactory proton conductivities.

Electrochemical engineering

There have been a number of projects in this area. We have developed chemical sensors based on polyaniline and its derivatives to measure the concentration of Vitamin C in food (US Patent 5,451,526), and used the same polymers for the corrosion protection of ferrous alloys. The metallization of insulator has always been our interest. A cost-effective method to metallise two dimensional patterns without photolithography and proprietary chemicals was granted a U.K. patent (UK Patent 2287472). The use of electrochemical impedance spectroscopy for the detection of fish tissue freshness was also completed a number of years ago.

SELECTED PUBLICATIONS

Xie, J.P., J.Y. Lee, D.I.C. Wang, and Y.P. Ting "Identification of active biomolecules in the high-yield synthesis of single-crystalline gold nanoplates in algal solutions". Smal, 2007. 3(4): 672-682.

Zeng, J.H., J. Yang, J.Y. Lee, and W.J. Zhou "Preparation of carbon-supported core-shell Au-Pt nanoparticles for methanol oxidation reaction: The promotional effect of the Au core", Journal of Physical Chemistry B, 2006. 110(48): 24606-24611.

Yang, J., J.Y. Lee, H.P. Too, and S. Valiyaveettil "A bis(p-sulfonatophenyl)phenylphosphine-based synthesis of hollow Pt nanospheres", Journal of Physical Chemistry B, 2006. 110(1): 125-129.

Yang, J., J.Y. Lee, H.P. Too, and G.M. Chow "Inhibition of DNA hybridization by small metal nanoparticles", Biophysical Chemistry, 2006. 120(2): 87-95..

Wang, Y., H.C. Zeng, and J.Y. Lee "Highly reversible lithium storage in porous SnO2 nanotubes with coaxially grown carbon nanotube overlayers", Advanced Materials, 2006. 18(5): 645-649.

Wang, Y. and J.Y. Lee, One-step "confined growth of bimetallic tin-antimony nanorods in carbon nanotubes grown in situ for reversible Li+ ion storage", Angewandte Chemie-International Edition, 2006. 45(42): 7039-7042.

Pei, H.Q., L. Hong, and J.Y. Lee "Embedded polymerization driven asymmetric PEM for direct methanol fuel cells", Journal of Membrane Science, 2006. 270(1-2): 169-178