Electrocatalytic Oxygen Reduction Reaction of Graphene Oxide and Metal-Free Graphene in an Alkaline Medium

Abstract

Graphene is a well-known two-dimensional material with a large surface area and is used for numerous applications in a variety of fields. Metal-free carbon materials such as graphene-based materials are widely used as an electrocatalyst for oxygen reduction reactions (ORRs). Recently, more attention has been paid to developing metal-free graphenes doped with heteroatoms such as N, S, and P as efficient electrocatalysts for ORR. In contrast, we found our prepared graphene from graphene oxide (GO) by the pyrolysis method under a nitrogen atmosphere at 900 °C has shown better ORR activity in aqueous 0.1 M potassium hydroxide solution electrolyte as compared with the electrocatalytic activity of pristine GO. At first, we prepared various graphene by pyrolysis of 50 mg and 100 mg of GO in one to three alumina boats and pyrolyzed the samples under a N2 atmosphere at 900 °C. The prepared samples are named G50-1B to 3B and G100-1B and G100-2B. The prepared GO and graphenes were also analyzed under various characterization techniques to confirm their morphology and structural integrity. The obtained results suggest that the ORR electrocatalytic activity of graphene may differ based on the pyrolysis conditions. We found that G100-1B (Eonset, E1/2, JL, and n values of 0.843, 0.774, 4.558, and 3.76) and G100-2B (Eonset, E1/2, and JL values of 0.837, 0.737, 4.544, and 3.41) displayed better electrocatalytic ORR activity, as did Pt/C electrode (Eonset, E1/2, and JL values of 0.965, 0.864, 5.222, and 3.71, respectively). These results display the wide use of the prepared graphene for ORR and also can be used for fuel cell and metal–air battery applications.

Adsorption and Recombination of H+ and H3O+ on Graphene-Supported Pt1, Pt13, and Pt14 Nanoclusters: A First Principles Study

“…A large surface area and high adsorption capacity are essential for hydrogen storage systems where the spillover effect plays a crucial role [19][20][21]. This effect improves the efficiency of proton transport from Pt nanoparticles to the ionomer, enhancing the performance of a graphene-based Pt electrocatalyst in PEMFC [22,23].…”

Enzymolytic Lignin-Derived N-S Codoped Porous Carbon Nanocomposites as Electrocatalysts for Oxygen Reduction Reactions

“…As a result, finding efficient and durable ORR electrocatalysts has become crucial. As is well known, platinum metals and platinumbased materials are still considered the most effective ORR catalysts [5]. However, due to low reserves, high costs, and poor cycle stability, Pt catalysts are difficult to meet the needs of large-scale applications [6,7].…”

Constructing FeS and ZnS Heterojunction on N,S-Codoped Carbon as Robust Electrocatalyst toward Oxygen Reduction Reaction

“…Metal-free doped carbons have attracted significant attention as efficient electrocatalysts for the adsorption of reactive intermediates during ORR, which can effectively regulate the electron and/or spin redistribution of the carbon matrix, thereby facilitating the ORR process [4][5][6]. It is well confirmed that S-doping is beneficial for the production of electron-withdrawing/donating groups, such as SOx-C or/and C-S-C species on the carbon plane [7], thereby modulating the electronic state of adjacent carbon atoms [8].…”