CuCo₂S₄@B,N-Doped Reduced Graphene Oxide Hybrid as a Bifunctional Electrocatalyst for Oxygen Reduction and Evolution Reactions

Abstract

In this report, a facile synthetic route is adopted for typically designing a hybrid electrocatalyst containing boron, nitrogen dual-doped reduced graphene oxide (B,N-rGO) and thiospinel CuCo 2 S 4 (CuCo 2 S 4 @B,N-rGO). The electrocatalytic activity of the hybrid catalyst is tested with respect to oxygen evolution (OER) and oxygen reduction (ORR) reactions in alkali. Physicochemical characterizations confirm the unique formation of a reduced graphene oxide–non-noble-metal sulfide hybrid. Electrochemical evaluation by cyclic voltammetry (CV) and linear-sweep voltammetry (LSV) reveals that the CuCo 2 S 4 @B,N-rGO hybrid possesses enhanced ORR and OER activity compared to the B,N-rGO-free CuCo 2 S 4 catalyst. The synthesized CuCo 2 S 4 @B,N-rGO hybrid demonstrates remarkable enhancement in catalytic performance with an improved onset potential (1.50 and 0.88 V) and low Tafel slope (112 and 73 mV dec –1 ) for both OER and ORR processes, respectively. In addition, the catalyst exhibits a diminutive potential difference (0.81 V) between the potential corresponding to the 10 mA cm –2 current density for OER and the half-wave potential for ORR. The superior catalytic activity and high durability of the hybrid material may be attributed to the synergistic effect arising from the metal sulfide and dual-doped reduced graphene oxide. The present study illuminates the possibility of using the dual-doped graphene oxide and metal sulfide hybrid as a competent bifunctional cathode catalyst for renewable energy application.

Electrical and Optical Properties of Controlled Reduced Graphene Oxide Prepared by a Green and Facile Route

“…The concentration of the solution was 12 mg/mL, which was then air-dried overnight. This was followed by thermal reduction processes to obtain rGO free-standing layers [23]. This provides an eco-friendly and safer yet facile rGO synthesis and oxygen reduction route, which also enables mass production.…”

Recent advances in nitrogen-doped graphene-based heterostructures and composites: mechanism and active sites for electrochemical ORR and HER

“…Another strategy for enhanced ORR activity was adopted by Roy Chowdhury et al , in which a hybrid catalyst was developed by employing CuCo 2 S 4 and dual heteroatom (B,N)-doped rGO. 171 The electrocatalytic investigations showed that the as-developed hybrid catalyst possessed enhanced bifunctional ORR and OER catalytic activity. In the case of the ORR, the as-synthesized CuCo 2 S 4 @B,N rGO exhibited significantly enhanced activity compared to CuCo 2 S 4 without B,N-doped rGO and Pt/C with a positive onset potential of 0.88 V, half-wave potential of 0.73 V and improved methanol tolerance.…”

Enhancing the oxygen evolution reaction of cobalt hydroxide by fabricating nanocomposites with fluorine-doped graphene oxide

“…34,35 The integration of electrocatalysts with a graphene oxide matrix often exhibits enhanced electrocatalytic activity due to a high surface area and good conductivity. 36,37 Heteroatom-doped graphene oxide nanocomposites showed strong electrocatalytic activity with excellent stability. 38,39 In particular, doping with highly electronegative F can modify the charge distribution of graphene and promote the adsorption process along with improving charge transfer and stabilizing 3d active metal centres.…”