Graphite Electrodes Modified with Platinum‐Nickel Nano‐Particles for Methanol Oxidation

Abstract

Methanol electro‐oxidation is investigated at graphite electrodes modified with various platinum and nickel nano‐particle deposits using cyclic voltammetry. The modified electrodes are prepared by the simultaneous electrodeposition of metals from their salt solutions using potentiostatic and galvanostatic techniques. They show enhanced catalytic activity towards methanol oxidation in KOH solution. The catalytic activity of platinum nano‐particles is found to be significantly affected by the presence of relatively small amounts of nickel deposits. A comparison is made between the electrocatalytic activity of Pt/C and (Pt‐Ni)/C electrodes. The results show that the methanol electro‐oxidation current increases with an increase in the nickel content. In particular, the highest catalytic activity is achieved for platinum to nickel deposits of 95%:5% (wt.‐%), in other cases the catalytic activity decreases. It is found that Ni enhances the catalytic activity of Pt by increasing the number of active sites, as well as through an electron donation process from Ni to Pt. This process takes place once the nickel hydroxide (Ni(OH)2)/nickel oxy‐hydroxide (NiOOH) transformation begins. The effect of the methanol concentration on the methanol oxidation reaction is investigated. The order of reaction, with respect to methanol, at the modified (Pt‐Ni)/C electrode is found to be 0.5.

Shaped Pd–Ni–Pt Core-Sandwich-Shell Nanoparticles: Influence of Ni Sandwich Layers on Catalytic Electrooxidations

“…It is generally believed that both of these catalytic reactions readily occur on more open (100) and (110) surfaces of Pt as opposed to the close-packed (111) facets . Significant improvements have been made to Pd and Pt MOR catalysts by addition of a transition metal to the structure, including alloyed and core–shell structures. − In our work, different shell thicknesses and sizes of Pd–Ni–Pt NPs are compared alongside the Pd–Pt core–shell NP control. Cyclic voltammetric (CV) and chronoamperometric curves (CA) were obtained for the catalysts of different sizes and Ni thicknesses to show both activity and stability.…”

Platinum-Based Nanostructured Materials: Synthesis, Properties, and Applications

“…Electrodeposition is a practical method for generating a variety of Pt and Pt-based nanomaterials. − This method involves the use of a two- or three-electrode electrochemical system, with the electrolyte serving as the source of Pt as well as the conducting medium. Deposition occurs by controlling either the electrode potential or the current density of the electrochemical cell.…”

Synthesis and Characterization of Nanocomposites with Strong Interfacial Interaction: Sulfated ZrO2 Nanoparticles Supported on Multiwalled Carbon Nanotubes

“…involved multiwalled carbon nanotubes (MWCNT) as the support for a cathode catalyst (highly dispersed Pt nanoparticles) of a direct methanol fuel cell (DMFC), and this catalyst achieved higher activity of the cathode oxygen reduction reaction (ORR) and better performance of the DMFC compared to using commercial carbons as the support. Besides the utilization of CNT to attenuate catalyst poisoning through their high surface area (minimizing the use of precious metal), another strategy to increase the CO tolerance of the Pt catalysts is to either use a Pt-based alloy or a Pt/metal oxide composite, − justified by the bifunctional mechanism and the electronic effect . More recently, emphasis has been placed on catalyst systems that combine Pt, metal oxide, and carbon, such as Pt-CeO 2 /C, Pt/SnO 2 –CNT, and Pt-V 2 O 5 /C .…”