Fabrication of novel metal-free "graphene alloy" for the highly efficient electrocatalytic reduction of H2O2.

Hydrogen peroxide (H2O2) is becoming significant due to its extensive applications, so determination of H2O2 is very important topic in analytical chemistry. Metal-free "graphene alloy" - nitrogen (N) and sulfur (S) heteroatoms co-doped reduced graphene oxide (NS-rGO) was produced via a simple one-step thermal annealing procedure using a mixture of 5-amino-2-mercapto-1,3,4-thiadiazole (AMT) and graphene oxide (GO). The obtained metal-free NS-rGO composite showed better electrocatalytic activity toward the reduction of H2O2 compared with the reduced graphene oxide (rGO). The enhanced performance was caused by the synergistic effect of N and S co-doping. Under optimum conditions, the constructed sensor demonstrated a linear response to H2O2 in the range of 7-18000μM, with a lower detection limit of 0.45μM (S/N=3), even better than some reported sensors based on noble metal nanoparticles. Moreover, the proposed sensor exhibited excellent analytical performance in terms of acceptable selectivity, excellent reproducibility and long-time stability. These results indicated that the NS-rGO composite was a promising metal-free electrocatalytic material for constructing H2O2 sensors. Additionally, NS-rGO composite was expected to be applied as catalysts for fuel cell applications, even for applications beyond fuel cells.