Synthesis and supercapacitor performance of Au-nanoparticle decorated MWCNT

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. (C) 2015 Elsevier B.V. All rights reserved.