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- MakaleYalnız künye2024Dual Capacitive Behavior of Hollow Porous Gold Nanoparticle/Multi-Walled Carbon Nanotube Composite Films as Anode and Cathode Electrode Materials for Supercapacitors
Bahar, Necmiye; Ekinci, Duygu
In this paper, composites of multi-walled carbon nanotubes decorated with hollow porous gold nanoparticles (HPAuNPs/MWCNTs) were prepared using wet chemistry methods, and their capacitive properties were evaluated in Na2SO4 aqueous solution on glassy carbon (GC) electrodes as both cathode and anode materials by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques. Also, the MWCNTs were studied under similar experimental conditions for comparison. The results revealed that the charge storage mechanisms of the MWCNTs/GC and HPAuNPs/MWCNTs/GC electrodes were electrostatic in the negative potential window, whereas they exhibited pseudocapacitive energy storage behavior in the positive potential region. Moreover, the HPAuNPs/MWCNTs/GC electrode yielded specific capacitance values of 57 and 49 F g−1 at a scan rate of 20 mV s−1 in the cathodic and anodic potential windows, respectively, which were higher than those of the MWCNTs/GC electrode (~9 F g−1). Graphic Abstract: [Figure not available: see fulltext.].
- MakaleYalnız künye2020Hollow porous gold nanoparticle/reduced graphene oxide composite films for electrochemical supercapacitor applications
Bahar, Necmiye; Ekinci, Duygu
Here, we report the synthesis of hollow porous gold nanoparticles-decorated reduced graphene oxide (HPAuNPs/RGO) nanocomposites and their electrochemical performances as active electrode material for supercapacitors. Accordingly, the HPAuNPs were first prepared using a simple solution phase template method according to the modified literature procedure, and the size control of hollow porous gold particles was achieved by varying the concentration of hydroquinone used as the reducing agent. Then, the surface of the RGO nanosheets was decorated with HPAuNPs through the self-assembly approach. The structural and morphological features of synthesized nanoparticles and nanocomposites were evaluated by spectroscopic and morphologic methods. Also, the electrochemical supercapacitive performances of the HPAuNPs/RGO/GC nanocomposite electrodes as both cathode and anode materials were analyzed in Na2SO4 solution using electrochemical methods. As a control sample, the RGO/GC electrode was also examined under identical experimental conditions. The results indicate that the composite materials display higher specific capacitances (107–325 F/g) compared with bare RGO (55 and 37 F/g) at a potential scan rate of 20 mV/s. Furthermore, it is obtained that the specific capacitances of the composite electrodes based on hollow porous gold nanoparticles are larger than those of previously reported supercapacitors with spherical gold nanoparticles/graphene as electrode materials. The improved electrochemical properties of the HPAuNPs/RGO/GC nanocomposite electrodes can be ascribed to the hollow and porous structure of the gold particles on RGO sheets.