Defective graphene nanosheets with heteroatom doping as hydrogen peroxide reduction catalysts and sensors

Abstract

The activities in the sequential and transient electrocatalysis of hydrogen peroxide reduction reaction (HPRR) of defective graphene nanosheet (dGN) were studied along with dGN without dopant obtained by hydrothermal reaction (dGNht), and N-, B-, S-, and Fe-doped dGNs. dGNs with 5−7-7−5 vacancy, 5–9, and point defects were successfully prepared by a green and sonoelectrochemical system, two graphite electrodes, and phosphate buffer electrolyte. The results showed that the specific activities in terms of electrochemical surface areas for dGN with N and O atom as the electron acceptor for C atom were greater than those of dGN B, S, and Fe atom as the electron donor. The weak activity by S-doped dGN could be attributed to the low bond polarity between C and S atom. The physical adsorption of hydrogen peroxide on the carbon catalysts limited the reaction kinetics. The amperometric curves of transient catalysis at −0.4 V vs. Ag/AgCl revealed that the reductive currents of the tested catalysts for sensing H2O2 follow the order: N-doped dGN > Fe-doped dGN > B-doped dGN > dGNht > S-doped dGN > dGN.