Mathew Wanees

Chemical Engineering

Microplasma-based Synthesis of Nanostructured Pt

Platinum is an excellent catalyst for the oxygen reduction reaction (ORR: O2 + 4H+ + 4e- →2H2O) in a fuel cell, and nanostructured platinum films with particle sizes in the sub-10 nm range are attractive due to their high activity and efficient Pt utilization. In this work, nanostructured Pt and Pt-alloy films and nanoparticles were deposited on doped silicon (Si) and indium tin oxide (ITO) substrates under a variety of conditions using a novel microplasma jet spray deposition technique. Pt precursor (Pt (II) hexafluoroacetylacetonate - Pt(hfac)) was sublimed and fed to the plasma anode capillary tube using an Ar carrier, with deposition pressures ranging from 10-760 torr. The resulting films were characterized using scanning electron microscope (SEM), energy dispersive x-ray analysis (EDX) and atomic force microscopy (AFM). Lower pressures and deposition times resulted in thinner and more porous Pt films, while higher pressures and larger jet-substrate distances yielded isolated Pt nanoparticles in the 2-4 nm range. The latter are currently being deposited with an additional Ni-based precursor (bis-cyclopentadienyl Ni - Ni(Cp)2) to form PtNi alloy nanoparticles to investigate the potential use of alloying to make more efficient use of Pt. Electrochemical testing of nanoparticle catalysts for ORR activity are underway.

UC Santa Barbara Center for Science and Engineering Partnerships UCSB California NanoSystems Institute UC Santa Barbara’s Parents Fund Campaign for UC Santa Barbara