Biogenic platinum from agricultural wastes extract for improved methanol oxidation reaction in direct methanol fuel cell

Platinum is the most commonly used catalyst in fuel cell application. However, platinum is very expensive, thus limits the commercialisation of fuel cell system due to the cost factor. This study introduces a biosynthesis platinum from plant extracts that can reduce the cost of platinum production compared to the conventional method and the hazardous during the production of the catalyst. The biogenic platinum was tested on a Direct Methanol Fuel Cell. Advanced biogenic of Pt nano-cluster was synthesized through a novel and facile of one-pot synthesis bio-reduction derived from natural source in the form of plant extracts as reducing agent. Several selected plant extracts drawn from agricultural waste such as banana peel, pineapple peels and sugarcane bagasse extracts were comparatively evaluated on the ability of phytochemical sources of polyphenols rich for the development of single-step synthesis for Pt NPs. Notably, the biogenic Pt NPs from sugar cane bagasse has superior electro-catalytic activity, the enhanced utilization efficiency of Pt and appreciable stability towards methanol oxidation reaction, whose ECSA value approximates 94.58 m²g⁻¹, mass activity/specific activity (398.20 mAmg⁻¹/0.8471 mA/cm²_Pt) which greater than commercial Pt black (158.12 mAmg⁻¹/1.41 mA/cm²_Pt).

Nanostructured Pd-Based Electrocatalyst and Membrane Electrode Assembly Behavior in a Passive Direct Glycerol Fuel Cell

The aim of this study was to synthesize, characterize, and observe the catalytic activity of Pd₁Au₁ supported by vapor-grown carbon nanofiber (VGCNF) anode catalyst prepared via the chemical reduction method. The formation of the single-phase compounds was confirmed by X-ray diffraction (XRD) and Rietveld refinement analysis, which showed single peaks corresponding to the (111) plane of the cubic crystal structure. Further analysis was carried out by field emission scanning emission microscopy (FESEM), energy dispersive X-ray analysis (EDX), nitrogen adsorption/desorption measurements, and X-ray photoelectron spectroscopy (XPS). The electrochemical performance was examined by cyclic voltammetry tests. The presence of mesoporous VGCNF as support enables the use of a relatively small amount of metal catalyst that still produces an excellent current density (66.33 mA cm^-2). Furthermore, the assessment of the kinetic activity of the nanocatalyst using the Tafel plot suggests that Pd₁Au₁/VGCNF exerts a strong electrocatalytic effect in glycerol oxidation reactions. The engineering challenges are apparent from the fact that the application of the homemade anode catalyst to the passive direct glycerol fuel cell shows the power density of only 3.9 mW cm^-2. To understand the low performance, FESEM observation of the membrane electrode assembly (MEA) was carried out, examining several morphological defects that play a crucial role and affect the performance of the direct glycerol fuel cell.

Molecular dynamics simulations of sodium alginate/sulfonated graphene oxide membranes properties

The influence of methanol as a solvent on the properties of sodium alginate/sulfonated graphene oxide (SA/SGO) membranes was explored in water-methanol mixed conditions with various methanol concentrations and temperatures through molecular dynamics simulations. The methanol uptake of the membrane showed an isolation phase determined from the simulation results. The distance between the sulfonic acid groups increased in higher methanol concentrations, as observed from S-S RDFs. Furthermore, the distance between the SA-chain RDFs and the solvent molecules was analysed to determine a) the affinity of water towards the sulfonic acid groups and b) the affinity of the aromatic backbone of the SA towards methanol molecules. A decrease in water molecule diffusion led to an increase in methanol diffusion and uptake. SA/SGO membranes exhibited a smaller diffusion coefficient than that for the Nafion membranes, as calculated from simulation results and compared to the experimental work. Additionally, the diffusion ability increased at higher temperatures for all permeants. The interaction information obtained is useful for DMFC applications.

Enhanced Proton Conductivity and Methanol Permeability Reduction via Sodium Alginate Electrolyte-Sulfonated Graphene Oxide Bio-membrane

The high methanol crossover and high cost of Nafion® membrane are the major challenges for direct methanol fuel cell application. With the aim of solving these problems, a non-Nafion polymer electrolyte membrane with low methanol permeability and high proton conductivity based on the sodium alginate (SA) polymer as the matrix and sulfonated graphene oxide (SGO) as an inorganic filler (0.02-0.2 wt%) was prepared by a simple solution casting technique. The strong electrostatic attraction between -SO₃H of SGO and the sodium alginate polymer increased the mechanical stability, optimized the water absorption and thus inhibited the methanol crossover in the membrane. The optimum properties and performances were presented by the SA/SGO membrane with a loading of 0.2 wt% SGO, which gave a proton conductivity of 13.2 × 10^-3 Scm^-1, and the methanol permeability was 1.535 × 10^-7 cm² s^-1 at 25 °C, far below that of Nafion (25.1 × 10^-7 cm² s^-1) at 25 °C. The mechanical properties of the sodium alginate polymer in terms of tensile strength and elongation at break were improved by the addition of SGO.

Penile measurements in normal adult Jordanians and in patients with erectile dysfunction

The purpose of this work was to determine penile size in adult normal (group one, 271) and impotent (group two, 109) Jordanian patients. Heights of the patients, the flaccid and fully stretched penile lengths were measured in centimeters in both groups. Midshaft circumference in the flaccid state was recorded in group one. Penile length in the fully erect penis was measured in group two. In group one mean midshaft circumference was 8.98+/-1.4, mean flaccid length was mean 9.3+/-1.9, and mean stretched length was 13.5+/-2.3. In group two, mean flaccid length was 7.7+/-1.3, and mean stretched length was 11.6+/-1.4. The mean of fully erect penile length after trimex injection was 11.8+/-1.5. In group 1 there was no correlation between height and flaccid length or stretched length, but there was a significant correlation between height and midpoint circumference, flaccid and stretched lengths, and between stretched lengths and midpoint circumference. In group 2 there was no correlation between height and flaccid, stretched, or fully erect lengths. On the other hand, there was a significant correlation between the flaccid, stretched and fully erect lengths. Comparing group 1 and group 2, the patients in group 1 were slightly older than in group 2 (P=0.035), but there was no significant difference in their height. However, there was a significant difference regarding the mean flaccid length 9.3 vs 7.7 (P=0.001), and the mean stretched length 13.5 vs 11.6 (P=0.000). We divided both groups into those who are less than 40 y of age, and over 40 y old. There was no statistical difference in the stretched and flaccid lengths between the younger and older individuals in each group. However, when we compared the stretched and flaccid lengths in those of less than 40 y old in group 1 and 2, a significant difference was noticed. Similarly, a significant difference in the stretched and flaccid lengths in those patients over 40 y of age was also present.