Characterization of Defined Pt Particles Prepared by Ultrasonic Spray Pyrolysis for One-Step Synthesis of Supported ORR Composite Catalysts

Abstract

Polygonal Pt nanoparticles were synthesized using ultrasonic spray pyrolysis (USP) at different precursor concentrations. Physicochemical analysis of the synthesized Pt particles involved thermogravimetric, microscopic, electron diffractive, and light absorptive/refractive characteristics. Electrochemical properties and activity in the oxygen reduction reaction (ORR) of the prepared material were compared to commercial Pt black. Registered electrochemical behavior is correlated to the structural properties of synthesized powders by impedance characteristics in ORR. The reported results confirmed that Pt nanoparticles of a characteristic and uniform size and shape, suitable for incorporation on the surfaces of interactive hosts as catalyst supports, were synthesized. It is found that USP-synthesized Pt involves larger particles than Pt black, with the size being slightly dependent on precursor concentration. Among ORR-active planes, the least active (111) structurally defined the synthesized particles. These two morphological and structural characteristics caused the USP-Pt to be made of lower Pt-intrinsic capacitive and redox currents, as well as of lower ORR activity. Although being of lower activity, USP-Pt is less sensitive to the rate of ORR current perturbations at higher overpotentials. This issue is assigned to less-compact catalyst layers and uniform particle size distribution, and consequently, of activity throughout the catalyst layer with respect to Pt black. These features are considered to positively affect catalyst stability and thus promote USP synthesis for improved properties of host-supported Pt catalysts.

Electrocatalytic Properties of Mixed-Oxide-Containing Composite-Supported Platinum for Polymer Electrolyte Membrane (PEM) Fuel Cells

“…Identical diffusion limited currents were reached on the Pt/75F-BP and Pt/75V catalysts, whereas the limiting current of the Pt/75BP catalyst was slightly higher, which may be due to the different morphology of the support (e.g., as a result of aggregation of primary particles to secondary ones). Furthermore, the literature suggests that a smaller limiting current density can be originated from reversible oxide formation/reduction on Pt, which leads to the growth of the Pt particles and, consequently, to the reduction of the actual active surface area [ 66 ]. Marginally lower diffusion-limited current density in the composite-supported Pt catalysts can also be caused by a slower diffusion of oxygen through the oxide layer covering the Pt nanoparticles [ 40 , 67 ].…”

Study of Gold Nanoparticles Conjugated with SARS-CoV-2 S1 Spike Protein Fragments

“…As a general rule, lower solute concentration results in smaller and rounder nanoparticles. The synthesised nanoparticles are collected in a different collection system of the USP device [37,38]. In this study, AuNP collection in demineralised water with a selected PVP stabiliser was used, which proved to be very effective.…”

Efficient Implementation of the Binary Common Neighbor Analysis for Platinum-Based Intermetallics

“…Furthermore, Table 1 gives a broad overview of all occurrences of a given LRO phase in binary alloy systems based on platinum-group metals (PGMs). This unique chemical ordering provides plenty of room for tuning the catalytic efficiency or stability of the platinum (Pt) shell or skin by a Pt-based intermetallic core or substrate through the ligand or strain effects [30,31]. Therefore, the capability to identify these LRO phases is important to the rational design of PGM nanocatalysts with reduced cost and high performance [32][33][34][35].…”