Xiaowei Teng's Research Group

The unique catalytic, electronic, and magnetic properties of nanostructured noble metals and their alloys have assured their widespread usage. The performance of these nanomaterials is strongly related to their size, shape, chemical composition, heterogeneous structure, interaction with support etc. The research activities in our group focus on vigorous, multi-disciplinary investigations of the design, characterization, and applications of nanomaterials. The novel catalytic and magnetic performance of these nanostructured materials may afford a solution to present and future energy-related problems. The four distinct research objectives described below spearhead this effort:

Nanocatalysts for direct ethanol fuel cell applications: In this area, we are interested in the solution phase synthesis of water soluble Pt-containing or Pt-fee nanoparticles as fuel cell catalysts. High level of controls in chemical composition and heterogeneous structure of nanoparticles can be expected through the dedicated synthetic design. The focus of our research is on the design of platinum-containing, or more important Pt-free nanoparticles for direct ethanol fuel cell reactions.

Metal oxide nanostructures for energy storage applications: To accelerate the adoption of renewable energy sources, energy storage devices are required to efficiently store electricity generated during off-peak hours for use during peak demand. Supercapacitors (SCs) are a class of energy storage device that fill a gap between high-energy-density batteries and high-power-density electrostatic capacitors. In this area, we are interested in the metal oxides nanomaterials, which are promising electrode materials in SCs, because of their large capacitance properties and their potential for multi-electron transfer during Faradaic reactions.

Heterogeneous Structure Characterization: The chemical and physical properties of a bimetallic system strongly depend on the heterogeneous nature of metal atoms, a combination of characterization techniques are required to decipher the actual structure of nanomaterials, especially when those bimetallic systems are in sub-nm to 2-3 nm size range. Research in our group often uses X-ray absorption spectroscopy (XAS) to investigate the structure of bimetallic nanomaterials at the National Synchrotron Light Source (NSLS) at the Brookhaven National Laboratory (BNL). We also use neutron scattering to analyse the mid-range order of nanomaterial using state-of-the-art facility at Nanoscale Ordered Materials Diffractometer (NOMAD) at Spallation Neutron Source (SNS), Oak Ridge National Laboratory (ORNL). The resuting information are then used to obtain unique structural dynamics information for the nanophases, and eventually help us establish structure-property correlation in many functional nanomaterials.

Renewed magnetic properties of 4d and 5d metal/alloy nanostructures: Magnetic material at the nanoscale presents surprising behavior that does not appear in its bulk form. In confined nanoscale systems, the reduced coordination and bonding favor more localized electronic states, as well as narrower bands and larger densities of states, bringing very exotic features to the magnetism. Several 4d and 5d metals display ferromagnetism, such as palladium, rhodium, ruthenium, and gold, in contrast to diamagnetism or paramagnetism in their bulk counterparts. We have targeted Pt, Au and AuPt alloy nanowires to study their size-, stoichiometry- and heterogeneous structure- dependent magnetic properties.