title: Formic acid-assisted synthesis of palladium nanocrystals and their electrocatalytic properties.
abstract: Palladium (Pd) nanocrystals have been synthesized by using formic acid as the reducing agent at room temperature. When the concentration of formic acid was increased continuously, the size of Pd nanocrystals first decreased to a minimum and then increased slightly again. The products have been investigated by a series of techniques, including X-ray diffraction, high-resolution transmission electron microscopy (HRTEM), UV-vis absorption, and electrochemical measurements. The formation of Pd nanocrystals is proposed to be closely related to the dynamical imbalance of the growth and dissolution rate of Pd nanocrystals associated with the adsorption of formate ions onto the surface of the intermediates. It is found that small Pd nanocrystals showed blue-shifted adsorption peaks compared with large ones. Pd nanocrystals with the smallest size display the highest electrocatalytic activity for the electrooxidation of formic acid and ethanol on the basis of cyclic voltammetry and chronoamperometric data. It is suggested that both the electrochemical active surface area and the small size effect are the key roles in determining the electrocatalytic performances of Pd nanocrystals. A "dissolution-deposition-aggregation" process is proposed to explain the variation of the electrocatalytic activity during the electrocatalysis according to the HRTEM characterization.
authors.affiliation: State Key Laboratory Breeding Base of New Fiber Materials and Modern Textile, Collaborative Innovation Center for Marine Biomass Fibers, Materials and Textiles of Shandong Province, Qingdao University , Qingdao 266071, P. R. China.
authors.forename: Qinchao
authors.initials: Q
authors.lastname: Wang
authors.forename: Yiqian
authors.initials: Y
authors.lastname: Wang
authors.forename: Peizhi
authors.initials: P
authors.lastname: Guo
authors.forename: Qun
authors.initials: Q
authors.lastname: Li
authors.forename: Ruixue
authors.initials: R
authors.lastname: Ding
authors.forename: Baoyan
authors.initials: B
authors.lastname: Wang
authors.forename: Hongliang
authors.initials: H
authors.lastname: Li
authors.forename: Jingquan
authors.initials: J
authors.lastname: Liu
authors.forename: X S
authors.initials: XS
authors.lastname: Zhao
mesh_terms: D002384:Catalysis; D055664:Electrochemical Techniques; D005561:Formates / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D005561:Formates; C030544:formic acid; D010165:Palladium