Synthesis and supercapacitor performance of Au-nanoparticle decorated MWCNT

• Au-multiwall carbon nanotube composites are applied as electrode materials for supercapacitor.
• Au NPs boosts the supercapacitor performance of Au-MWCNT compared to bare MWCNTs.
• Lower metal loading with smaller particle size is more effective in enhancing the capacitance behavior.
• This behavior is mostly related to the interactions that take place at metal-graphitic interface.
• Lowering of Schottky barriers and work function of the metal contributes to the enhanced capacitance.

Au-multiwall carbon nanotube (Au-MWCNT) composites with well-dispersed Au-nanoparticles (NPs) are prepared using a simple and efficient solution method and applied as electrode materials for electrochemical capacitors. Au NP loading is varied, and electrochemical performance of the Au-MWCNT composites is investigated using cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) measurements. Au NP decoration boosts the supercapacitor performance of the Au-MWCNT composite compared with bare MWCNTs. Composite with lower loading of 10 wt% Au loading displays higher specific capacitance (105 F g − 1) compared with bare MWCNTs (48 Fg − 1) at a current density of 0.8 A g− 1, demonstrating that the Au NP decoration significantly enhances the supercapacitor performance of the composite despite no participation of Au in faradic reaction. By varying the metal loading of the composites, it is revealed that lower metal loading with smaller particle size is more effective in enhancing the capacitance behavior of the composites compared with ones with higher metal loading. This behavior is mostly related to the interactions that take place at metal-graphitic interface which may include lowering of Schottky barriers and work function of the metal.

Au-MWCNTs with small Au particle size and low loading show better capacitance compared to bare MWCNTs. Interactions at metal-graphitic interface may have a role in this capacitance enhancement.Figure optionsDownload as PowerPoint slide