title: Block copolymer lithography of rhodium nanoparticles for high temperature electrocatalysis.
abstract: We present a method for forming ordered rhodium nanostructures on a solid support. The approach makes use of a block copolymer to create and assemble rhodium chloride nanoparticles from solution onto a surface; subsequent plasma and thermal processing are employed to remove the polymer and fully convert the nanostructures to metallic rhodium. Films cast from a solution of the triblock copolymer poly(styrene-b-2-vinyl pyridine-b-ethylene oxide) dissolved in toluene with rhodium(III) chloride hydrate were capable of producing a monolayer of rhodium nanoparticles of uniform size and interparticle spacing. The nanostructures were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. The electrocatalytic performance of the nanoparticles was investigated with AC impedance spectroscopy. We observed that the addition of the particles to a model solid oxide fuel cell anode provided up to a 14-fold improvement in the anode activity as evidenced by a decrease in the AC impedance resistance. Examination of the anode after electrochemical measurement revealed that the basic morphology and distribution of the particles were preserved.
authors.affiliation: Division of Physics, Mathematics & Astronomy, California Institute of Technology, Pasadena, California 91125, USA. daboyd@caltech.edu
authors.forename: David A
authors.initials: DA
authors.lastname: Boyd
authors.forename: Yong
authors.initials: Y
authors.lastname: Hao
authors.forename: Changyi
authors.initials: C
authors.lastname: Li
authors.forename: David G
authors.initials: DG
authors.lastname: Goodwin
authors.forename: Sossina M
authors.initials: SM
authors.lastname: Haile
mesh_terms: D002384:Catalysis; D004563:Electrochemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011327:Printing; D012238:Rhodium / Q000737:chemistry*; D013696:Temperature
chemical_list: D011108:Polymers; D012238:Rhodium