Edge-halogenated graphene nanosheets as an efficient metal-free electrocatalyst for hydrogen evolution reaction

Abstract

Application of carbonic materials as catalysts has recently been considered due to some advantages like tunable molecular structures, easy synthesis methods, abundance, and high tolerance in acidic and alkaline media. Here, a new metal-free electrocatalyst of halogenated reduced graphene oxide was prepared using cyclic voltammetry X (F, Br, and I)-RGO electrodeposition method. The prepared electrocatalysts were studied as a novel metal-free electrocatalyst for the hydrogen evolution reaction, and the presence of several halogen and oxygen functional groups on the surface of nanosheets was verified by the furrier transform infra-red, FT-IR, spectroscopy, and the presence of doped halogens on the RGO surface was confirmed by energy-dispersive X-ray, EDX, spectroscopy. The structural features and surface morphology of electrocatalysts were investigated by scanning electron microscopy (SEM) analysis. The electrochemical treatment of the X (F, Br, I)-RGO electrode was studied by some techniques like electrochemical impedance spectroscopy, EIS, chronoamperometry, CA, and linear sweep voltammetry, LSV. The X (F, Br, I)-RGO catalyst showed a lower onset potential (−0.81 V. vs. SHE), higher exchange current density (3.1 × ×10−1 mA cm−2), and lower charge transfer resistance (1.09 Ω cm2) related to the RGO catalyst due to the high active sites by heteroatoms and graphene nanosheets.