Shape-Controlled Synthesis of Gold Nanoprism and Nanoperiwinkles with Pronounced Electrocatalytic Activity

Abstract

We report the one-pot shape-controlled aqueous synthesis of triangular gold nanoprisms (GNPMs) and nanoperiwinkles (GNPWs) and their electrocatalytic activity toward reduction of oxygen and oxidation of methanol. The GNPMs and GNPWs were synthesized using 5-hydroxytryptamine (HT) as a reducing/stabilizing agent at room temperature. The UV−visible absorption spectrum of the nanostructured colloidal particles exhibits transverse and longitudinal surface plasmon bands at 535 and 900 nm, respectively. The transmission electron microscopy measurement shows that the nanostructured particles have prism and periwinkle-like morphology. The concentration of HT controls the shape and morphology of the nanostructured particles. The GNPMs have the size of 70−110 nm whereas GNPWs have the size of 150−230 nm. The X-ray diffraction profiles of GNPMs and GNPWs reveal that the nanoparticles are composed of mainly a Au(111) lattice plane. The GNPMs and GNPWs were self-assembled on a three-dimensional silicate network derived from (3-mercaptopropyl)trimethoxysilane, and their spectral and electrochemical properties have been investigated. The UV−visible diffuse reflectance spectral measurement shows that both GNPM and GNPW retain their morphology on the silicate network. The nanoparticles on the silicate network show excellent electrocatalytic activity toward oxidation of methanol and reduction of oxygen. The electrocatalytic activity of GNPMs and GNPWs is higher than the spherical gold nanoparticles.

Recent Advances in the Liquid‐Phase Synthesis of Metal Nanostructures with Controlled Shape and Size for Catalysis

“…A recent study reported on the shape-controlled synthesis of triangular gold nanoprisms (70-110 nm size) and nanoperiwinkles (150-230-nm size) for electrocatalytic methanol oxidation (163). The nanostructures were synthesized using 5-hydroxytryptamine as a reducing/stabilizing agent at room temperature.…”

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

“…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.…”

“…[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. [14] The highest activity was obtained with Au nanospheres with diameters of 20 nm.…”

Recent Development of Active Nanoparticle Catalysts for Fuel Cell Reactions

“…[26] Au nanocubes of 40 nm were produced by reducing HAuCl 4 Á 3H 2 O on Au seeds in the presence of CTAB and L-ascorbic acid. [27] Nanoprism Au NPs were made by mixing HAuCl 4 and 5-hydroxytryptamine in aqueous solution, [28] and nanoporous Au were prepared by de-alloying AuAg alloy. [29] Although the ORR catalyzed by these Au catalysts was found to follow the 2-or 4-electron pathways, as observed from the bulk Au electrodes, the catalytic mechanism was not well understood.…”