Novel fabrication of PdCu nanostructures decorated on graphene as excellent electrocatalyst toward ethanol oxidation

In this study, the electrochemical reduction reaction of copper(II) formate on the graphene/glassy carbon electrode (G/GCE) surface in the HCl (5 wt.%) was employed for fabrication of the PdCu nanostructures by galvanic displacement reaction. This method has a number of advantages including being environmentally-friendly, simplicity, inexpensiveness and fast. The PdCu nanostructures decorated on the G/GCE were fabricated in two steps: (1) electrochemical reduction reaction of copper(II) formate to Cu on the G/GCE and (2) the galvanic replacement reaction between Cu and Pd²⁺ ions. The physical and electrochemical properties of as-prepared PdCu/G were investigated via Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, Cyclic Voltammetry, Chronoamperometry, and Electrochemical Impedance Spectroscopy. The PdCu/G compositional effect on ethanol oxidation in alkaline media is investigated. The results were shown that the catalytic activity and durability of PdCu/G catalyst are superior to those of Pd/C electrocatalyst for ethanol oxidation. The PdCu/G increased the current density 6.2 times more than Pd/C with a 50 mv negative shift in onset potential for electrooxidation of ethanol. Besides, the novel PdCu/G catalyst exhibits large electrochemically active surface area, lower apparent activation energy, higher levels of stability, poisoning tolerance, and lower charge transfer resistance compared to the Pd/C for the oxidation of ethanol.     

Preparation of silicone oil nanoemulsion softeners using different surfactants and their effect on physical characteristics of polyester fabric

Silicone oil nanoemulsion softeners with different particle sizes can be prepared using different surfactants with various ratios aminosilicone oil, surfactants concentration and time of mixing. The silicone oil nanoemulsion softeners could penetrate well into the polyester fibers; therefore, they can induce desirable physicochemical properties in the fabric. In current study, we first prepared silicone oil nanoemulsion softeners by designing via DOE software and with different particle sizes using nonyl phenol, octyl phenyl ether and fatty alcohol surfactants, and we investigated them using dynamic light scattering (DLS) and transmission electron microscope (TEM) techniques. In DOE software, the effect of various independent variables of emulsification process such as surfactant type, oil weight fraction, surfactant concentration and time of mixing on dependent variables were studied including particle size, z-average and width. Then, we examined the physical characteristics of polyester fabric by applying silicone oil macro, micro and nanoemulsion softeners. The treated fabrics with these softeners were compared with each other through the physical properties. The scanning electron microscopy (SEM) analysis showed the polyester fabric treated with silicone nanoemulsion softeners appeared to have smoother fiber surface. To prove the penetration of silicone particles into the fabric fibers, a cross section was taken from the cross section of polyester fabric by microtome in liquid nitrogen. The TEM images from cross section of fabrics treated with the silicone oil nanoemulsion softeners confirmed that the nanoparticles had penetrated well into the polyester fibers; therefore, they could induce desirable physicochemical properties in the fabric.