Various Carbon Chain Containing Linkages Grafted Graphene with Silver Nanoparticles Electrocatalysts for Oxygen Reduction Reaction

Abstract

In this study, we have synthesized an efficient catalyst by various carbon chain containing linkers grafted graphene with silver nanoparticles (AgNPs)-decorated GO-S-(CH 2 ) x -SH (where x = 2, 3, 4 and denoted as GO-C x -Ag) for oxygen reduction reaction (ORR). The structural and morphological properties have investigated via several instrumental methods. Among those catalysts, the GO-C 2 -Ag has showed an excellent electrocatalytic performance by cyclic voltammetry (CV) and hydrodynamic techniques for ORR in alkaline media. Hydrodynamic voltammetry reveals that the GO-C 2 -Ag modified electrode has catalyzed effectively at higher potential. The overall electrocatalytic results showed that the GO-C 2 -Ag has better activity toward ORR and demonstrated nearly four electron transfer pathway into H 2 O due to much grafting of linker molecule and smaller size of AgNPs. The value of transferred electron number (n) and other kinetic parameters have demonstrated that the GO-C 2 -Ag is highly facilitated than that of GO-Ag and other GO-C x -Ag to electrocatalytic oxygen reduction. Graphene, which is discovered by Geim's group in UK in 2004, is composed of a single sheet of conjugated sp 2 carbon atoms packed into a honeycomb crystal structure.1 It is an attractive material due to its unique physical and chemical properties such as its outstanding thickness, tensile strength (130 Gpa), thermal conductivity (5,300 W/mK), allowable current density (108 A/cm 2 ), and mobility (200,000 cm 2 /Vs). 2-5 However, the oxidized graphene (GO) surface is highly functionalized with oxygenated groups, such as ketones, epoxides, hydroxyls and carboxylates, 6 which make them targets for covalent modification. Graphene has been recognized and used as an important material in various technologies in chemistry such as, displays, rechargeable batteries, solar cells, automobiles, fuel cells (FCs). 7 In recent years, due to global warming, energy issues are in the spotlight. Thus, many studies have been conducted on carbon nanomaterials supported metal nanoparticles (NPs) for both anodic and cathodic reactions in FCs including oxygen reduction reaction (ORR).ORR is important for energy conversion systems in FCs 7,8 and metal air batteries. 9 It is well-known that a platinum (Pt)-based catalyst in an acidic solution has the highest chemical stability among electrochemically active catalysts. However, Pt-based catalysts are too expensive to make FCs commercially viable. Under acidic conditions, due to the high dissociation energy (494 kJ/mol) of oxygen molecules, electrochemical oxygen reduction requires a high overpotential, and the reaction rate is slow.10 Moreover, Pt has suffered several problems such as, poor drivability and toxic effects of methanol crossover/carbon monoxide in direct methanol fuel cells (DMFCs).In the last few years, because of these shortcomings of Pt-based electrocatalysts, studies have been conducted to develop alternative non Pt catalysts. Typical alternative metallic catalysts are included with several metals such ...

Determination of Dopamine by Dual Doped Graphene-Fe2O3in Presence of Ascorbic Acid

“…Graphene has already been used in various fields, especially in catalysis, and sensors. [16][17][18][19][20][21][22][23] The graphene sheets can be readily synthesized by reducing oxygen functional groups such as hydroxyl, epoxide, and carboxyl groups (on planes and edges) present on the surface of graphene oxide (GO). 24 Doping is one of the simple and efficient way to increase the catalytic activity of graphene catalysts because they not only exhibit excellent electrocatalytic activity but also possess other advantages including low cost, better stability, and environment-friendly.…”

Synergistic Effect of 1,4-Benzenedimethaneamine Assembled Graphene Supported Palladium for Formaldehyde Oxidation Reaction in Alkaline Media

“…12 The choice of a suitable supporting material is an important factor that may affect the performance of supported electrocatalysts, owing to the support-catalyst interactions z E-mail: swjeon3380@naver.com and surface reactivity. 23 A derivative of benzylamine molecules, 1,4-benzenedimethaneamine (BDMA) having two amino linkers on opposite sides acts as a stabilizer for metal NPs. These oppositely positioned -NH 2 group are suitable to react with acid group via condensation reaction to form a C-N bond.…”

“…These oppositely positioned -NH 2 group are suitable to react with acid group via condensation reaction to form a C-N bond. 12,23 Graphene or reduced graphene oxide (rGO) is an extendable 2D carbon sheet, in which carbon atoms are packed in a hexagonal lattice like a honeycomb. Numerous fascinating properties including high specific surface area, excellent mechanical strength and flexibility, and unparalleled thermal and electrical conductivity as well as superior electronic properties are making it as a perfect support material for metal NPs-based nanosized catalysts.…”

The Determination of Dopamine in Presence of Serotonin on Dopamine-Functionalized Electrochemically Prepared Graphene Biosensor

“…1 Due to its high electrical conductivity, large surface area, long-term stability and unique mechanical flexibility, [4][5][6] graphene has already been used in various fields, especially in sensors, 2,7,8 capacitor 9 and electrochemical catalysis. [10][11][12][13] DA, the most important among the classes of catecholamines, plays an important role in the brain system. It is responsible for the functions of the central nervous, renal, hormonal, and cardiovascular systems.…”

“…It is, however, the GO contains epoxy and carboxyl functional groups along with the other oxygenated groups 17,18 which providing a number of chemically active sites for addition with amine group of DA via a condensation reaction. 13 This approach cannot only prevent the agglomeration of graphene due to the bigger space between two sheets for DA molecules 19 but also can further improve the electrocatalytic activity due to surface functionalization. 17 Thus, it is promising to utilize DA to reduce GO, and then to incorporate it via condensation reaction, because of the advantages of DA addition including the non-toxic property, restraining agglomeration, and covalent functionalization of DA-GO.…”