Platinum Particles Electrochemically Deposited on Multiwalled Carbon Nanotubes for Oxygen Reduction Reaction in Acid Media

Abstract

Platinum nanoparticles supported on multiwalled carbon nanotubes (Pt/MWCNT) were prepared using controlled electrochemical deposition from Ar-saturated H 2 PtCl 6 solution. The electrodeposition parameters were varied to observe change in the surface morphology and electrocatalytic activity of the Pt/MWCNT catalysts for oxygen reduction reaction (ORR). Surface morphology of the prepared catalysts was studied by scanning electron microscope (SEM) and scanning transmission electron microscope (STEM). For electrochemical characterization of the Pt/MWCNT electrocatalysts, CO-stripping and cyclic voltammetry (CV) experiments were performed in 0.05 M H 2 SO 4 solution. The ORR was studied in acid medium using the rotating disk electrode (RDE) method. The results obtained were analyzed and compared to those of commercial Pt/C. The size, shape and distribution of Pt particles as well as the electrochemical behavior of Pt/MWCNT modified electrodes showed strong dependence on the deposition parameters. The catalyst materials prepared by electrochemical deposition showed higher specific activities than commercial Pt/C catalyst. The Pt/MWCNT cathode materials showed remarkable stability during repetitive potential cycling in 0. Proton exchange membrane fuel cell (PEMFC) is identified as one of the most promising environmentally friendly sustainable energy conversion devices that efficiently convert fuel energy into electricity through electrochemical processes. [1][2][3] In comparison to the conventional internal combustion engine, low-temperature fuel cells are preferred for energy conversion in vehicles because of its green operating system, high efficiency and renewable energy resources.4,5 One of the most critical challenges for commercializing fuel cells is the development of more efficient, highly active and durable electrocatalysts to improve the sluggish kinetics of the oxygen reduction reaction (ORR). To date, Pt-based cathode catalysts have shown significantly high electrocatalytic activity toward the ORR as compared to other metals, alloys, core-shell structures, mixed metal oxides and nonnoble metal catalysts.6-15 Considerable efforts have been dedicated to minimize the amount of Pt loading and improve its electrocatalytic activity and durability, mainly because of its scarcity and high cost. [16][17][18][19]

Low-Loading of Pt Nanoparticles on 3D Carbon Foam Support for Highly Active and Stable Hydrogen Production

“…From the SEM images, histogram plots, and Figure 2E one could observe a clear decrease in particle size and increase in particle density as the deposition overpotential increased. This suggests that at low electrodeposition overpotential (−0.2 V SCE ), the nucleation rate is slower than the rate of the nucleus growth on the carbon foam surface (Hussain et al, 2017 ). That is, it is more favorable for Pt to deposit on the existing nuclei and grow before the next nucleus is formed on carbon surface (heterogeneous reduction), resulting in larger and fewer number of Pt nanoparticles (Figure 2A ).…”

Oxygen Electroreduction on Pt Nanoparticles Deposited on Reduced Graphene Oxide and N‐doped Reduced Graphene Oxide Prepared by Plasma‐assisted Synthesis in Aqueous Solution

“…Nevertheless, trace amount of Cl À anions may remain from precursors and further exacerbate the catalyst efficiency by blocking Pt surface active sites. [41][42][43][44] Formation of the Pt surface oxides can be seen in the anodic sweep at a potential above 0.8 V in both media, which are reduced at~0.7 V in the cathodic sweep. In PEM fuel cells, chloride impurities arise from the membrane electrode assembly (MEA) preparation and less than 5-ppm of chloride residues can result in a voltage loss of 50 mV and affect the open-circuit voltage.…”

Understanding the Electrooxidation of Dimethyl Ether on Pt3Pd3Sn2 Supported on a Mixture of Carbon Materials

“…Therefore, the best performance exhibited with higher MWCNT content in the support mixture (75M25B) is associated with having better exposed metallic active sites, rather than due to improved dispersion of the catalyst on the support. 29 The particle size for the nanoparticles supported on selected supports was calculated by taking more than 100 randomly picked nanoparticles from the STEM images and a histogram showing the particle size distribution (PSD) is displayed in Figs. 3f-3h.…”