Electrochemical deposition of platinum nanoparticles on different carbon supports and conducting polymers

Abstract

Electrodeposition of Pt nanoparticles under potentiostatic conditions was performed on several types of carbon electrode supports: a commercial macroporous carbon (which can be considered as a three-dimensional electrode), glassy carbon, graphite and conducting polymers (polyaniline and poly-o-aminophenol). The platinum nanoparticles were obtained by different Potential Step Deposition (PSD) methods in 5 mM H 2 PtCl 6 + 0.5 M H 2 SO 4 aqueous solutions. The effect of the final potential, time and number of steps on the quantity, distribution and size of the platinum nanoparticles deposited on the supports was analysed. The mechanism of the electrochemical deposition of platinum was studied by applying theoretical models found in the literature, being the progressive nucleation mechanism the most consistent with our results. In addition, the chemical state and morphology of the electrodeposited materials The prepared composites have been tested for the electro-oxidation of methanol. 2.-EXPERIMENTAL Preparation of the supportsDifferent carbon materials have been used to prepare the working electrodes for the platinum electrodeposition: macroporous carbon disc, glassy carbon and graphite.The macroporous carbon discs, which were cut from a macroporous carbon sheet (thickness = 0.3 mm, mean pore size 0.7 µm, exposed geometric area 2.91 cm 2 )provided by Poco Graphite (DFP-1) were washed in an ultrasonic bath with distilled water at room temperature for 30 minutes. The graphite (Ellor+35) and glassy carbon (CV25) were rods of 0.3 cm in diameter from Carbone Lorraine.In all cases, the materials were first treated with sandpaper, and were then polished with two different diamond suspensions (particle sizes 1 and 0.25 µm, respectively), and finally washed in an ultrasonic bath with ultrapure water for 5 minutes.The conducting polymers layers were electrochemically deposited on glassy carbon by cyclic voltammetry between 0.06 and 1.10V from a 0.1 M aniline or o -5 aminofenol in a supporting electrolyte of 0.5 M H 2 SO 4 at a scan rate of 50 mV s -1 .Although different expressions can be found for film thickness determination in literature, an EQCM experiment [27] was used to calculate film thickness from polymer peak voltammetric charge. Platinum electrodepositionThe electrodeposition of platinum particles on the different electrodes was performed in a conventional electrochemical cell of three electrodes at room temperature. All the reagents used were of analytical grade, and these and other materials were used without f urther purification. An EG&G potentiostat/galvanostat model 263A controlled by the program POWER SUITE was employed, so the values of current and time were monitored by a computer. For all the experiments the counterelectrode was a platinum wire. The reference electrode was a reversible hydrogen electrode (RHE), immersed in 0.5M H 2 SO 4 solution, which was connected to the working electrode compartment by a Luggin capillary.All solutions were prepared with high-purity water (resistivity =18 MΩ·...

Flexible ruthenium oxide-activated carbon cloth composites prepared by simple electrodeposition methods

“…Furthermore, the On the other hand, the use of electrochemical methods for the preparation of composite materials provides a number of advantages over other techniques. For example, the preparation procedure is simple and the growth of the film can be modulated by experimental parameters such as potential or applied current, the composition of the precursor solution and the deposition time [34][35][36].…”

Confined palladium colloids in mesoporous frameworks for carbon nanotube growth

“…The large contribution of alkane formation via direct hydrogenation of alkyne makes this catalytic system rather different from those in the literature (see, for example, [22] and references therein). This phenomenon may be explained by the state in which the hydrogenation catalyst is present in our case.…”

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Effect of Carbon Support on the Properties of Electrochemically Deposited Platinum and Polyaniline

“…The choronoamperogram for graphite shows evidence of hydrogen evolution and a slight decrease in current over time, most likely due to the increased resistance discussed previously. 23 This hydrogen evolution leads to faster nucleation, and uneven growth of the Pt layer, seen in the SEM image ( Figure 4B). The platinum deposition on the coke sample results in the opposite.…”