MnO ₂ / Co ₃ O ₄ with N and S co‐doped graphene oxide bimetallic nanocomposite for hybrid supercapacitor and photosensor applications

Abstract

This report presents the synthesis of MnO 2 /Co 3 O 4 with N and S co-doped graphene oxide (GO) hybrid composite by hydrothermal route for supercapacitor and photosensor applications. MnO 2 /Co 3 O 4 nanoflakes and nanoparticles were directly grown on dual N and S doped GO sheets, where doping was achieved using a single reagent thiourea in one-pot synthesis. Individual Co 3 O 4 and MnO 2 electrodes have poor reversibility and cycling properties due to electrolytic instability and low electrical conductivities. However, the hybrid provides good catalytic properties, and combined with highly conducting two-dimensional GO it can reduce mismatching properties due to high conductivity and layered structure. The incorporated composite sheet-like structure provides good mechanical strength with high conductivity, permitting easy ion penetration into the electrode, and providing considerably more active surfaces. Thus, the proposed hybrid material delivers significantly improved performance for supercapacitor and/or photosensor applications, achieving 614 F.g À1 specific capacitance at 1 Ag À1 , and exceeding 95% retention up to 10 000 cycles. This composite material also shows good photosensing with 1 order of increased current under visible light. K E Y W O R D Scobalt oxide, manganese oxide, MnO 2 /Co 3 O 4 @N and S co-doped GO, nitrogen and sulfur co-doping, photosensor, supercapacitor

MnO2-based materials for supercapacitor electrodes: challenges, strategies and prospects

“…the porous structure and improving the stability of the structure. [127][128][129][130][131][132] Up to now, great progress has been made and the exploration of heterojunctions is not over yet, so further efforts are still needed. In the future research process, it can focus on combining MnO 2 with advanced materials (such as COF, POP, etc.)…”

“…The enhanced conductivity also increased the synergy of the components, which promoted the electrode reaction kinetics. Adaikalam et al 131 improved the problems of poor reversibility and stability in the presence of single MnO 2 and Co 3 O 4 electrodes by N and S double doped GO sheets. The overall mechanical strength and electrical conductivity of the material was also enhanced and allowed more ion penetration into the electrode.…”

“…The electronic structure is regulated by the interaction generated by binding with other substances, promoting the charge transfer kinetics, building the porous structure and improving the stability of the structure. 127–132 Up to now, great progress has been made and the exploration of heterojunctions is not over yet, so further efforts are still needed. In the future research process, it can focus on combining MnO 2 with advanced materials (such as COF, POP, etc. )…”

Heteroatom Codoped Graphene: The Importance of Nitrogen

“… 226 Sulfur and nitrogen codoped graphene nanomaterials have broad visible absorption 223 , 224 and superb luminescence properties. 226 − 232 They can be used in bioimaging. 233 , 234 Also, they were reported to have a fluorescence quantum yield 9.3 times higher than that of undoped graphene.…”

Nitrogen-doped reduced graphene oxide-polyaniline composite materials: hydrothermal treatment, characterisation and supercapacitive properties

“…8,9 However, GO on its own is a poor electrode material for ECs due to limited electro-active sites and its insulating nature. 10,11 For example, a high amount of GO in a Ni–metal–organic framework-GO-graphene nanoplatelet EC electrode was reported to lower electric energy storage capabilities due to the increased insulating effect from GO. 12 The conducting properties of graphene can be restored in GO by reducing it through chemical, thermal, and other methods.…”