Christmas‐Tree‐Shaped Palladium Nanostructures Decorated on Glassy Carbon Electrode for Ascorbic Acid Oxidation in Alkaline Condition

Abstract

Christmas-tree-shaped Pd nanostructures were synthesized using a simple one-step electrodeposition method with no additives on a glassy carbon electrode (GCE) surface. Growth of the hierarchical nanostructures was optimized through the applied potential, deposition time, and precursor concentration. Comprehensive characterization techniques such as scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Xray powder diffraction (XRD), and cyclic voltammetry (CV) were used to characterize structural features of the Christmas-treeshaped Pd nanostructures. Our Christmas-tree-shaped Pd nanostructures showed excellent catalytic activity for ascorbic acid (AA) electro-oxidation in the alkaline condition. The modified electrode exhibited current density of 4.5 mA cm À 2 : much higher than that of unmodified GCE (0.6 mA cm À 2 ). This simple electrodeposition technique with well-defined hierarchical Pd nanostructures is expected to offer new perspectives using Pdbased nanostructured surfaces in different research areas.

Palladium nanoparticles combined with reduced graphene oxide and multiwall carbon nanotubes for alkaline ascorbic acid oxidation

“…We also found an oxidation peak without the presence of AA at −0.15 V for the development of Pd 2+ from Pd 0 under the alkaline condition. 52,60) In our recent article we also observed the PdO peak in a similar potential for the Pd catalyst in the 1 M KOH solution. 52) The peak potential of AA oxidation (−0.04 V) is more positive than the PdO peak (−0.15 V) as shown in Fig.…”

“…52,60) In our recent article we also observed the PdO peak in a similar potential for the Pd catalyst in the 1 M KOH solution. 52) The peak potential of AA oxidation (−0.04 V) is more positive than the PdO peak (−0.15 V) as shown in Fig. 4(a).…”

“…The reduction of PdO to Pd was attributed to a reduction peak detected at −0.5 V in 1 M KOH solution. 52) A large capacitive current is observed in Fig. 4(a), which is very common for rGO/ MWCNT systems.…”

“…The Pd (111) plane corresponds to the diffraction peak at 40.1°. 52,53) Both Pd/rGO/MWCNT and rGO/MWCNT have peaks at 25.8°corresponding to the C (002) plane to an interlayer spacing of 3.45 Å. [54][55][56] The broad diffraction peak of the C (002) plane in Pd/rGO is attributable to the lesser degree of agglomeration of the rGO sheets.…”

“…With a 5.2 eV gap, two peaks were found with binding energies of 340.8 eV and 335.6 eV for Pd (3d 3/2 ) and Pd (3d 5/2 ). 34,39,41,52,58) According to XPS measurements, Pd NPs were in a metallic state in Pd/rGO/MWCNT. The chemical reduction process converts Pd precursor to metal Pd.…”