Novel cost-effective synthesis of non-doped turbostratic graphene from a graphite intercalation compound: development of a durable and stable electrocatalyst for the oxygen reduction reaction

Abstract

Expensive and high-temperature methods like chemical vapour deposition and epitaxial growth are mainly investigated for turbostratic graphene preparation, whereas cost-effective production by a top-down approach from graphite is presented here. Interlayer catalytic exfoliation of randomly oriented Fe₂O₃ intercalated graphite sheets with H₂O₂ resulted in turbostratic graphene. The retained Fe species on the sheets are further removed by acid treatment. The formation of turbostratic graphene is evident from the Moiré fringes in the transmission electron microscopic images and the multiplicity of spots in the selected area electron diffraction patterns. The development of cost-effective, durable electrocatalysts for the oxygen reduction reaction (ORR) is vital due to the high cost and poor methanol tolerance of commercial Pt/C. Here, non-doped turbostratic graphene layers have been effectively used for the ORR. Due to the excellent electronic properties of suspended graphene together with the robustness of few-layer graphene, the prepared turbostratic graphene shows promising ORR activity, satisfactory cyclic stability, a positive onset potential, and a reasonably good half-wave potential. The absence of metal in the catalyst results in superior methanol tolerance in comparison with Pt/C. The current density is higher than the commercial 20 wt% Pt/C catalyst and most of the reported graphene-based systems.