Multiwalled Carbon Nanotubes Composited with Palladium Nanocatalysts for Highly Efficient Ethanol Oxidation

Abstract

Carboxyl multi-walled carbon nanotubes (MWNTs-COOH) decorated with different palladium (Pd) nanoparticle loadings were synthesized by thermally decomposing different amounts of palladium acetylacetonate (Pd(acac) 2 ) in a refluxing xylene solution with a fixed amount of dispersed MWNTs-COOH. The increased ratio of D band/G band and the decreased area ratio of oxygen containing groups (COOH, C-O and C=O) to C-C group suggested an increased occupation of defects on MWNTs. Transmission electron microscope (TEM) revealed different distributions of Pd NPs on the MWNTs with the variation of Pd(acac) 2 amount and the particle size increased with increasing the Pd loading. A relatively higher conversion of Pd(acac) 2 to Pd (76.21%) was achieved when the initial precursor ratio of Pd(acac) 2 to MWNTs was 2 : 1 (product denotes as Pd/MWNTs-(2:1)). The Pd/MWNTs-2:1 catalysts were demonstrated to exhibit the most efficient performance toward ethanol oxidation reaction (EOR) among all the precursor ratios, which is evaluated by the highest Pd mass-based peak current density (1.23 A/mg Pd ) and stable current density (0.175 A/mg Pd ) in cyclic voltammetry (CV) and chronoamperometry (CA). In addition, both reduced charge-transfer resistance and increased reaction kinetics with increasing the Pd loading were obtained from electrochemical impedance spectroscopy (EIS) and Tafel characterization.

Preparation and Electrocatalytic Characteristics of PdW/C Catalyst for Ethanol Oxidation

“…The strong diffraction peak of PdW/C catalyst was also found at 40.14°, corresponding to the plane of (1 1 1). No significant peak shift is observed for the PdW/C (1:1) [29]. The average particle size of the prepared PdW/C nanoparticles (d) was estimated by using the Scherrer Equation [30] after background subtraction from Pd (1 1 1) peak at 2θ of 40°, agreeing with TEM results, which is as shown in Table 1.…”

Enhanced charge-carrier transfer by CdS and Ag2S quantum dots co-sensitization for TiO2 nanotube arrays

“…Among them, the perpendicularly oriented upon the base, highly ordered TiO 2 nanotube arrays (TNAs) maintain one-dimensional carrier pathways for electrons and holes. Thus TNAs are considered ideal support materials because of their superb photoelectrochemical characteristics [11][12][13][14][15][16]. Apparently enhanced photoelectrochemical properties have been realized in narrow-bandgap semiconductor QD sensitized TNAs.…”

Sonochemical Synthesis of Two Dimensional C3N4 Nanosheets Supported Palladium Composites and Their Electrocatalytic Activity for Oxygen Reduction and Methanol Oxidation Reaction

“…However, the cost of palladium is lower than that of platinum and it is at least fifty times more abundant on the earth than Pt, as a result, it could be a good substitute for Pt as the catalyst in fuel cells. [9][10][11] Because catalysis is a surface effect, the catalyst needed to have surface area as high as possible. 2D nanosheets as emerging nanomaterials exhibit unique properties that originate from their atomically thin layer, high surface area and specific physicochemical properties.…”