Palladium nanoparticles supported on mesoporous biocarbon from coconut shell for ethanol electro-oxidation in alkaline media

Abstract

Palladium nanoparticles supported on carbon Vulcan XC72 (Pd/C) and biocarbon (Pd/BC) synthesized by sodium borohydride process were used as catalysts for ethanol electro-oxidation in alkaline media. The biocarbon (BC) from coconut shell with mesoporous and high surface area (792 m 2 g −1) was obtained by carbonization at 900 °C and the hydrothermal treatment in a microwave oven. The D-band and G-band intensity ratio (I D /I G) from Raman analysis showed high disorder of the biocarbon, while X-ray photoelectron spectroscopy (XPS) suggests higher percentage of oxygen groups on the surface of biocarbon than of Vulcan XC72. From X-ray diffraction (XRD), it was observed peaks in 2θ degree related to the face centered cubic (fcc) structure of palladium and the mean crystallite sizes calculated based on the diffraction peak of Pd (220) were 5.6 nm for Pd/C and 5.3 nm for Pd/BC. Using Transmission Electron Microscope (TEM), it was observed particles well dispersed on both carbons support materials. The electrocatalytic activity of the materials was investigated by cyclic voltammetry (CV) and chronoamperometry (CA) experiments. The peak current density (on CV experiments) from ethanol electro-oxidation on Pd/BC was 50% higher than on Pd/C, while the current density measured at 15 min of CA experiments was 80% higher on Pd/BC than on Pd/C. The higher catalytic activity of Pd/BC might be related to the large surface area of the biocarbon (792 m 2 g −1) vs (239 m 2 g −1) of Vulcan carbon, the defects of the biocarbon structure and higher amount of oxygen on the surface than Carbon Vulcan XC 72.

Insights into the Role of Poly(vinylpyrrolidone) in the Synthesis of Palladium Nanoparticles and Their Electrocatalytic Properties

“…It is found that the binding energy of Pd 3d 5/2 of Pd-NPC and Pd-PC is 335.80 eV, whereas Pd 3d 5/2 of Pd-NPC-PVP and Pd-PC-PVP decreases to a lower value of 334.10 eV attributed to the high charge density of Pd atoms. Meanwhile, the N 1s spectra of Pd-NPC-PVP and Pd-PC-PVP show peaks at 399.4 eV, illustrating the presence of PVP according to the reported literature. , Figure B shows the presence of PdO 3d 5/2 bonds at 355.9 eV for Pd-NPC-PVP and Pd-PC-PVP, which is not shown in Figure A. At the same time, there is no corresponding bond for the PdO compound in the O 1s spectrum; therefore, the presence of PdO bonds might be attributed to the combination of Pd and PVP.…”

“…Meanwhile, the N 1s spectra of Pd-NPC-PVP and Pd-PC-PVP show peaks at 399.4 eV, illustrating the presence of PVP according to the reported literature. 58,59 Figure 7B shows the presence of PdO 3d 5/2 bonds at 355.9 eV for Pd-NPC-PVP and Pd-PC-PVP, which is not shown in Figure 7A. At the same time, there is no corresponding bond for the PdO compound in the O 1s spectrum; therefore, the presence of PdO bonds might be attributed to the combination of Pd and PVP.…”

Optimization of the catalytic support and membrane for the electrochemical reforming of ethanol in alkaline media

“…Among the different investigated catalysts, it can be observed that Pd/CNF LS and Pd/C Vulcan exhibited higher electrocatalytic activity for the EOR than the other anodic catalysts. This could be attributed to the physicochemical properties of each material, such as the dispersion of the Pd in the different carbonaceous supports, which is directly related to the particle size, or the oxygen‐containing species of CNFs, which can also be used to effectively increase the number of anchoring sites for the immobilization of metal–ligand systems …”

Black phosphorous/palladium functionalized carbon aerogel nanocomposite for highly efficient ethanol electrooxidation

“…1,2 Among different types of fuel cells, liquid fuel cells (LFCs) have considerable advantages in terms of easy handling, low operating temperatures, and the availability of a wide range of liquid fuels such as ethanol, methanol and formic acid. [3][4][5] The ease of producing ethanol from the fermentation of biomass makes its use as a fuel in LFCs an attractive choice. Despite these appealing features, the realization of efficient, cost-effective ethanol LFCs is still hampered by some issues such as the slow and inefficient ethanol electrooxidation (EEO) reaction, the poisoning of the catalysts by the intermediate species especially in acidic media, and the high cost of the catalysts, of which platinum (Pt) is the most famous.…”