Co3O4 nanoparticles anchored on nitrogen-doped reduced graphene oxide as a multifunctional catalyst for H2O2 reduction, oxygen reduction and evolution reaction

Tingting Zhang,Fengzhan Sun,Yuqing Lin,Jiahui Wang,Yongqi Ding,Manchao Wang,Chuansheng He,Lin Peng

doi:10.1038/srep43638

Tingting Zhang, Fengzhan Sun + Show 6 more

Open Access

https://doi.org/10.1038/srep43638

Copy DOI

Journal: Scientific Reports	Publication Date: Mar 8, 2017
Citations: 112	License type: open-access

Affiliation: Capital Normal University

Abstract

This study describes a facile and effective route to synthesize hybrid material consisting of Co3O4 nanoparticles anchored on nitrogen-doped reduced graphene oxide (Co3O4/N-rGO) as a high-performance tri-functional catalyst for oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and H2O2 sensing. Electrocatalytic activity of Co3O4/N-rGO to hydrogen peroxide reduction was tested by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry. Under a reduction potential at −0.6 V to H2O2, this constructing H2O2 sensor exhibits a linear response ranging from 0.2 to 17.5 mM with a detection limit to be 0.1 mM. Although Co3O4/rGO or nitrogen-doped reduced graphene oxide (N-rGO) alone has little catalytic activity, the Co3O4/N-rGO exhibits high ORR activity. The Co3O4/N-rGO hybrid demonstrates satisfied catalytic activity with ORR peak potential to be −0.26 V (vs. Ag/AgCl) and the number of electron transfer number is 3.4, but superior stability to Pt/C in alkaline solutions. The same hybrid is also highly active for OER with the onset potential, current density and Tafel slope to be better than Pt/C. The unusual catalytic activity of Co3O4/N-rGO for hydrogen peroxide reduction, ORR and OER may be ascribed to synergetic chemical coupling effects between Co3O4, nitrogen and graphene.

Highlights

Catalytic activity for the oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and immobilizing enzymes for further applications in fabrication of hydrogen peroxide biosensor[13,14,15]
The oxygen-containing functional groups of reduced grapheme oxide (rGO) were beneficial for the nucleation and anchoring of nanocrystals on the sheets to achieve covalent attachments, which help to shape the uniform formation of Co3O435,36
These results again confirmed that Co3O4 nanoparticles have been anchored on N-rGO, Co2+ and Co3+ in the crystal structure of Co3O4 are being considered to be playing a vital role in improving catalytic performance of oxygen reduction reaction and oxygen evolution reaction[37]

Summary

Results and Discussion

The XPS spectrum for Co2p shown in Fig. 3D reveals two major peaks with binding energies at 780.1 and 795 eV, corresponding to Co2p3/2 and Co2p1/2, respectively, with a spin energy separation of 15 eV, which is attributed to the Co2+ oxidation state, indicating that a portion of Co3+ is reduced to Co2+ with generating oxygen vacancies[17] These results again confirmed that Co3O4 nanoparticles have been anchored on N-rGO, Co2+ and Co3+ in the crystal structure of Co3O4 are being considered to be playing a vital role in improving catalytic performance of oxygen reduction reaction and oxygen evolution reaction[37].

Conclusions

Author Contributions

Additional Information