Sonoelectrochemical exfoliation of highly oriented pyrolytic graphite for preparing defective few-layered graphene with promising activity for non-enzymatic H2O2 sensors

Defective few-layered graphene (dFLG) was successfully prepared by using a detergent and a sonoelectrochemical method. The fast exfoliation of dFLG with step defects results from the rapid interaction of sodium n-octyl sulfate with a highly oriented pyrolytic graphite electrode on application of an oscillation power of 192 W and a potential of around 3 V (vs. Ag/AgCl). Simultaneously, the application of an oxidation potential leads to the formation of C-O and O-C = O groups on the dFLG as confirmed by X-ray photoelectron spectroscopy. The dFLG with such defects was deposited on a glassy carbon electrode (GCE) where it displays improved electrocatalytic activity in catalyzing the oxidation of H2O2, best at a working voltage of -0.4 V (vs. Ag/AgCl). Its sensitivity (211.14 mu A center dot mM(-1)center dot cm(-2)) is improved when compared to a GCE modified with reduced graphene oxide or graphene oxide and the linear analysis range extends from 0.02 to 2.9 mM. Real sample analysis of milk demonstrated the feasibility of using such a dFLG-based sensor for H2O2.