Gold nanoparticles synthesized in a water-in-oil microemulsion: electrochemical characterization and effect of the surface structure on the oxygen reduction reaction

Electrochemical Oxidation of Small Organic Molecules on Au Nanoparticles with Preferential Surface Orientation

“…The XRD patterns of the different Au nanoparticles clearly show ad istinct relative intensity of the different diffraction peaks, indicatingt he presence of ap referential orientation parallel to the substrate in agreement with previouso bservations by Eguchi et al [41] In addition to TEM and XRD analyses, the electrochemical characterization of the nanoparticles was performed by using Pb underpotentiald eposition (UPD) to prove the existence of the preferential surface sites and the absence of undesirable faceting. [42,43] The Pb UPD on gold single-crystal electrodes has showns urface-structure dependencea nd has been used for the characterization of preferentially oriented nanoparticles. [44] Figure2As hows the Pb UPD on both types of gold nanoparticles.…”

“…[42,43] Subsequently,t or emove the Pb/ PbO 2 after the electrochemical cleaning process, the supported particles were dipped in 0.1 m HNO 3 for 10 min. [45] Figure2B shows the blank voltammetric response of the Au nanoparticles after this cleaningp rocedure.…”

Shape‐Dependent Electrocatalysis: Oxygen Reduction on Carbon‐Supported Gold Nanoparticles

“…The final product of O 2 reduction on Au nanocubes and nanospheres was observed to be H 2 O, whereas on nanorods the two-electron reduction of O 2 to H 2 O 2 dominates. [9][10][11][12] In contrast, triangular Au nanoprisms and nanoperiwinkles, composed mainly of a Au(111) lattice plane, support the two-step, four-electron reduction of O 2 . [13] More recently the ORR activity of Au nanospheres of two different sizes and Au nanorods has been reported.…”

“…It has been demonstrated that the ORR activity of these materials can be improved by designing nanoparticles with a certain shape. [7][8][9][10][11][12][13][14] The electrocatalysis of diO2 reduction on shape-controlled Pd nanoparticles has also been investigated recently. [15][16][17][18] Studies on Au single-crystal electrodes have shown that Au(100) is the most active lowindex plane for ORR in alkaline media.…”

“…[26] The fact that the ORR activity of Au electrodes depends on the crystallographic orientation suggests a route to synthesise active catalysts by preparing AuNPs with certain shapes, namely nanocubes, as these have preferential (100) facets. [9][10][11][12]27] In comparison with Au nanospheres or nanorods, nanocubes have shown much higher electrocatalytic activity towards the ORR. The final product of O 2 reduction on Au nanocubes and nanospheres was observed to be H 2 O, whereas on nanorods the two-electron reduction of O 2 to H 2 O 2 dominates.…”