Facile Synthesis of Bimetallic Pt-Ag/Graphene Composite and Its Electro-Photo-Synergistic Catalytic Properties for Methanol Oxidation

Abstract

A Pt-Ag/graphene composite (Pt-Ag/GNs) was synthesized by the facile aqueous solution method, in which Ag + was first transformed into Ag 2 O under UV light irradiation, and then Ag 2 O, Pt 2+ , and graphene oxide (GO) were simultaneously reduced by formic acid. It was found that Pt-Ag bimetallic nanoparticles were highly dispersed on the surface of graphene, and their size distribution was narrow with an average diameter of 3.3 nm. Electrocatalytic properties of the Pt-Ag/GNs composite were investigated by cyclic voltammograms (CVs), chronoamperometry (CA), CO-stripping voltammograms, and electrochemical impedance spectrum (EIS) techniques. It was shown that the Pt-Ag/GNs composite has much higher catalytic activity and stability for the methanol oxidation reaction (MOR) and better tolerance toward CO poisoning when compared with Pt/GNs and the commercially available Johnson Matthey 20% Pt/C catalyst (Pt/C-JM). Furthermore, the Pt-Ag/GNs composite showed efficient electro-photo-synergistic catalysis for MOR under UV or visible light irradiation. Particularly in the presence of UV irradiation, the Pt-Ag/GNs composite exhibited an ultrahigh mass activity of 1842.4 mA·mg −1 , nearly 2.0 times higher than that without light irradiation (838.3 mA·mg −1 ).

Effect of Metal Substrate on Electrocatalytic Property of Palladium Nanowire Array for High Performance Ethanol Electro-Oxidation

“…Both Pd alloys/C and Pd alloys are coated and immobilized on the GCE by an ionomer, most commonly Nafion. , Dispersed pure Pd nanowires have also been used as the electrocatalysts on GCE, , but their activities are often limited by the 2D structure. Nanowires in the form of array structures have been investigated to provide higher surface areas for the reaction to take place and could be performed without the Nafion coating, which reduced product accumulation and provided faster molecular diffusions throughout. , Although several different types of substrates have been used, ,− ,− no systematic study has been conducted on the substrate effect of the nanowire array electrodes on their overall performance.…”

Catalysis for Low-Temperature Fuel Cells

“…The enhancement was attributed to the formation of a Pt shell completely covering the Cu core, leading to maximum electrochemical surface areas. The works of Xu et al and Wang et al regard the utilization of graphene-supported Pt-based catalysts for the electro-oxidation of methanol [25,26]. Xu et al propose a one-pot synthetic method to produce composites based on Pt and graphene mediated by a template (polyamidoamine or chitosan) [25].…”

“…Xu et al propose a one-pot synthetic method to produce composites based on Pt and graphene mediated by a template (polyamidoamine or chitosan) [25]. The use of templates leads to a stronger interaction between Pt and the support resulting in improved MOR activity, whereas the addition of a second metal in Pt-Ag catalysts supported on graphene also resulted in improved performance for the MOR [26], particularly in the presence of UV irradiation. Qayyum et al explored the synthesis of Pt nanoparticles by pulsed laser deposition [27].…”