title: A facile synthesis of MPd (M = Co, Cu) nanoparticles and their catalysis for formic acid oxidation.
abstract: Monodisperse CoPd nanoparticles (NPs) were synthesized and studied for catalytic formic acid (HCOOH) oxidation (FAO). The NPs were prepared by coreduction of Co(acac)(2) (acac = acetylacetonate) and PdBr(2) at 260 °C in oleylamine and trioctylphosphine, and their sizes (5-12 nm) and compositions (Co(10)Pd(90) to Co(60)Pd(40)) were controlled by heating ramp rate, metal salt concentration, or metal molar ratios. The 8 nm CoPd NPs were activated for HCOOH oxidation by a simple ethanol wash. In 0.1 M HClO(4) and 2 M HCOOH solution, their catalytic activities followed the trend of Co(50)Pd(50) > Co(60)Pd(40) > Co(10)Pd(90) > Pd. The Co(50)Pd(50) NPs had an oxidation peak at 0.4 V with a peak current density of 774 A/g(Pd). As a comparison, commercial Pd catalysts showed an oxidation peak at 0.75 V with peak current density of only 254 A/g(Pd). The synthesis procedure could also be extended to prepare CuPd NPs when Co(acac)(2) was replaced by Cu(ac)(2) (ac = acetate) in an otherwise identical condition. The CuPd NPs were less active catalysts than CoPd or even Pd for FAO in HClO(4) solution. The synthesis provides a general approach to Pd-based bimetallic NPs and will enable further investigation of Pd-based alloy NPs for electro-oxidation and other catalytic reactions.
authors.affiliation: Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA.
authors.forename: Vismadeb
authors.initials: V
authors.lastname: Mazumder
authors.forename: Miaofang
authors.initials: M
authors.lastname: Chi
authors.forename: Max N
authors.initials: MN
authors.lastname: Mankin
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.forename: Önder
authors.initials: Ö
authors.lastname: Metin
authors.forename: Daohua
authors.initials: D
authors.lastname: Sun
authors.forename: Karren L
authors.initials: KL
authors.lastname: More
authors.forename: Shouheng
authors.initials: S
authors.lastname: Sun
mesh_terms: D000497:Alloys / Q000138:chemical synthesis / Q000737:chemistry*; D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D005561:Formates / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D000497:Alloys; D005561:Formates; C030544:formic acid; D003035:Cobalt; D010165:Palladium; D003300:Copper