Organic Chemistry: Current Research
Open Access

Structural and Electrochemical Characteristics of Platinum-Containing Electrocatalysts

Weon Chung^{* *}Correspondence: Weon Chung, Department of Chemistry, University of Warsaw, Ulju-gun, Ulsan, South Korea, Email:

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Low-temperature Proton Exchange Membrane Fuel Cell (PEMFC) catalysts is significantly impacted by their level of durability. In order to improve the stability of catalysts, the choice of carbon support is essential. In this analysis, two different types of carbon supports-the conventional support, Vulcan XC-72, and the carbon support with a high degree of graphitization, ECS-002402-were used to create Pt/C samples using the polyol synthesis method. Transmission Electron Microscopy (TEM) is one technique for evaluating structural properties, revealing that materials G1 and G2 had typical nanoparticle sizes of 3.7 and 4.2 nm, respectively. The oxygen reduction reaction occurred in accordance with the four-electron mechanism on all catalysts. Variations in ESA and ORR activity after 1000 cycles, along with changes in the upper potential values of 0.7, 1.0, 1.2, and 1.4 V, were used to evaluate durability. Accelerated stress testing revealed that the G1 material had the highest residual activity at 1.4 V (165 A/g) (Pt). The best mode of 0.4 and 1.4 V was selected based on the findings of comparing several ADT methods and it should be used for future research evaluating the longevity of Pt/C catalysts.

Today, the search for alternative energy sources is becoming more and more prominent. Fuel cells are one potential source of current (FC). FCs is an extremely effective, dependable, longlasting, and eco-friendly method of generating energy. With an operating temperature range of 25°C -100°C, low-temperature fuel cells are becoming increasingly important. They are distinguished from high-temperature fuel cells by their autonomy, high power, environmentally friendly fuel, and portability. Fuel cells use specialized platinum-containing catalysts to speed up the rate of chemical processes. As a result, one of the most crucial components of the fuel cell is its nanostructured catalyst, which is based on platinum or its alloy Nanoparticles (NP) coated on carbon material with a developed surface. The carbon support is crucial when it comes to increasing the stability of catalysts while they are operating. The hydrophobic/hydrophilic characteristics of the surface, the width, shape, and volume of the pores and the level of corrosion resistance are all indicative of highly scattered carbon supports.

Utilizing carbon support with an ideal surface area is essential when synthesising Pt electrocatalysts. High Electrochemically active Surface Area (ESA), Oxygen Reduction Reaction (ORR) activity and durability throughout FC operation are the essential requirements for electrocatalysts. High activity and stability are challenging to combine because they depend differently on the structural and morphological properties of platinum-containing electrocatalysts.

Long-term testing in Membrane-Electrode Assemblies (MEA) is the best technique to assess a catalyst's durability. Since this approach of evaluating stability is costly, time-consuming, and energy-intensive, the earliest stages of the research are conducted in laboratories. Accelerated Degradation Testing (ADT) involves repeatedly performing cyclic potential sweeps in various potential ranges, which is used to evaluate the stability of electrocatalysts. The ESA and specific activity values of the catalyst are tracked as part of the ADT process.

Platinum Nanoparticles (NPs) dissolution, NP separation from the carbon surface, particle aggregation, metal reprecipitation, and carbon support oxidation are all potential causes of electrocatalyst deterioration. For Pt-containing electrocatalysts, there are primarily two types of degradation mechanisms: those linked to the oxidation of carbon support or the deterioration of Pt nanoparticles. Depending on the ADT's probable operating range, each degrading process makes a different contribution. It is extensively discussed how degradation processes are mostly connected to the transformation of metal NPs dispersed throughout the support surface at potentials between 0.4 and 1.0 V. The main source of contribution at potentials above 1.1 V comes from material degradation processes caused by oxidation of the carbon support. As a result, it is possible for support parts with deposited NPs to become isolated as well as for metal NPs to separate, lose electrical contact, and cause a decrease in the ESA. It is significant to remember that the characteristics and type of carbon support play a significant role in how long materials last. It was noted that supports with a high degree of graphitization showed less of a tendency to degrade and oxidise when electrocatalysts were operating. Therefore, it may be possible to create electrocatalysts with high activity and stability by using supports with a high degree of graphitization.