Hybrid Nanomaterials Based on Graphene and Gold Nanoclusters for Efficient Electrocatalytic Reduction of Oxygen

Abstract

Nanocomposites based on gold nanoclusters (AuNCs) with polyvinyl pyrrolidone as ligand and reduced graphene oxide (RGO) have been prepared and employed as efficient electrocatalysts for oxygen reduction reaction (ORR). AuNCs were synthesized through a wet chemical approach and then loaded onto the RGO. The as-prepared hybrid materials were pyrolyzed to remove the organic ligands. The composites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) as well as other techniques. Electrochemical tests demonstrated that the hybrid materials exhibited effective ORR activity in alkaline media. Among a series of samples tested, the pyrolyzed sample with 50 % AuNCs mass loading exhibited the best activity, superior than AuNCs alone, RGO alone, and the others, in terms of onset potential and kinetic current density as well as durability. The method here may provide a generic approach to prepare supported noble metal nanoclusters with excellent reactivity and robust stability for ORR.Electronic supplementary materialThe online version of this article (doi:10.1186/s11671-016-1552-0) contains supplementary material, which is available to authorized users.

Au101–rGO nanocomposite: immobilization of phosphine-protected gold nanoclusters on reduced graphene oxide without aggregation

“…17,18 However, the size-specific catalytic activity of AuNCs has often been difficult to determine experimentally as clusters are prone to aggregation either during deposition or activation on the support, 19,20 or deactivation of the catalyst following initial reaction. 21 Therefore, methods for the fabrication of gold cluster-based catalysts resilient to aggregation are in high demand in nanomaterials, 22 catalysis 4,16,23,24 and sensing communities. 25,26 It has been shown that the successful deposition of AuNCs on surfaces depends on various factors, such as the type of support and ligand, synthetic conditions and cluster-support interactions.…”

“…It has been demonstrated that small metal nanoparticles (not size specific) such as Ag 27 , Pd 28 and Au, 21,29,30 can be immobilized on reduced graphene oxide (rGO). 31 rGO has a two-dimensional structure with extraordinary properties, such as high electrical conductivity, large surface area and high charge mobility.…”

Oxygen Reduction Reaction Catalyzed by Noble Metal Clusters

“…Recently, our group has also conducted some work regarding employing Au clusters based nanocomposite for ORR. We integrated polyvinyl pyrrolidone (PVP)-protected Au nanoclusters with reduced graphene oxide (RGO) as the catalyst [61] and found that the nanocomposite possessed markedly higher long-term stability in ORR than Pt/C. Subsequently, we fabricated nanocomposite based on p-mercaptobenzoic acid-functionalized Au nanoclusters, Au 102 (p-MBA) 44 , and porous carbon nanosheets [62].…”

Methanol Tolerant Oxygen Reduction Reaction Electrocatalysis using Size‐Specific Triphenylphosphine‐Ligated Gold Nanoclusters

“…In recent decades, sub-2 nm sized gold nanoclusters and complexes (AuNCs) have been explored as promising electrocatalysts for ORR, [11][12][13][14][15][16][17][18][19][20][21][22][23][24] hydrogen evolution reaction (HER), [25] hydrogenation of terminal alkynes into alkenes, [26] CO oxidation, [27] styrene oxidation [28,29] and benzyl alcohol oxidation. [30,31] The unusual catalytic behaviour of the AuNCs compared to bulk Au is due to a series of size-dependant properties, including high surface-to-volume ratio, [15,32,33] molecular-like electronic properties, [34] and ligand density (if present).…”

“…Despite the fact that ligand removal is considered as a pathway to make more available active sites, it is challenging to retain the cluster size without ligands. [16][17][18][19][20][21][22][23][24] AuNCs ligands are typically organo-thiols or phosphines but can have a wide variety of organic functionality, which can alter the reactivity of AuNCs. [37] For instance, AuNCs protected by bulky ligands have lower ligand density, particularly at larger sizes, resulting in higher ORR activity compared to aliphatic and linear ligands.…”