Low temperature preparation of a graphene–cobalt microsphere hybrid by borohydride-initiated reduction for enriching proteins and peptides

Abstract

A graphene–cobalt microsphere hybrid was prepared by the chemical reduction of a mixture containing graphene oxide and cobalt chloride. It was found that a little amount of potassium borohydride or sodium borohydride could initiate the hydrazine-reduction of the mixture at a low temperature of 80 °C. The structure of the material was investigated by scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, vibrating sample magnetometery, Fourier transform infrared spectroscopy, Raman spectroscopy, and Brunauer–Emmett–Teller (BET) techniques. The average size of the cobalt microspheres on graphene sheets was measured to be ∼590 nm. Magnetic investigations indicated that the graphene–cobalt microsphere hybrid exhibited ferromagnetic behavior at room temperature. In addition, the magnetic hybrid was successfully employed in the enrichment and identification of low-abundance proteins and peptides in combination with mass spectrometry.