In situ FTIR spectroscopic studies of (bi)sulfate adsorption on electrodes of Pt nanoparticles supported on different substrates

Controlled Surface Structure for In Situ ATR-FTIRS Studies Using Preferentially Shaped Pt Nanocrystals

“…This is different from most of the results obtained on a continuous pc-Pt film (preparation by electroless deposition) by ATR-FTIRS (see also [6,12]) and of IRRAS studies using bulk polycrystalline or single crystalline electrodes [44,47,48], where the (bi)sulfate bands showed the normal positive polarity. Bjerke et al [31] first reported a progressive change of the IR band shape and polarity of linearly adsorbed CO l , as the degree of platinization of the platinum electrode was increased.…”

“…Varying systematically both the thickness and grain size of continuous nanostructured Pt films, Gong et al [34] found a continuous change for the IR band polarity of adsorbed CO l from a negative-going to a positive-going monopolar band, with a bipolar band in an intermediate range, with increasing thickness and grain size. On the other hand, Zeng et al [48] also reported a reversed polarity for (bi)sulfate IR bands on Pt nanoparticles (100-300 nm size) electrodeposited on various substrates in IRRAS measurements in an external reflection configuration. Nevertheless, abnormal IR absorption cannot be correlated to a critical particle size alone, since on supported Pt catalysts with nanoparticles of below 5 nm in diameter, normal IR absorption was obtained [18,37,38].…”

In Situ FTIR Spectroscopy: Probing the Electrochemical Interface during the Oxygen Reduction Reaction on a Commercial Platinum High‐Surface‐Area Catalyst

“…If we take a closer look at the spectra, several absorption bands associated with potential‐dependent processes at the electrochemical interface can be identified; in particular a change in the water density at the interface, structural changes (reversible oxidation) of the carbon support, and the specific adsorption of spectator species on the Pt catalyst. Although an unambiguous assignment of all peaks that occur in the spectra is difficult, we refer to previous investigations of less complex catalyst systems, that is, bulk Pt and pure carbons for the assignment of the absorption bands …”

“…The setup enables us to scrutinize the role of strongly and weakly adsorbed anions during the ORR. The interaction of anions with Pt has been studied previously by infrared reflection adsorption spectroscopy (IRRAS) on single and polycrystals and on large (100–300 nm in diameter) electrodeposited Pt particles in H 2 SO 4 electrolyte. However, no studies have been conducted on particles in a size regime below 100 nm, on commercially applicable carbon‐supported catalysts, or during kinetic ORR measurements, that is, under well‐defined mass transport conditions.…”

Novel in situ electrochemical deposition of platinum nanoparticles by sinusoidal voltages on conducting polymer films

“…Recently, a great deal of interest has been devoted to innovative synthesis route of Pt nanoparticles, for example by the help of ultrasound [16]. Another possibility might lie in the in situ preparation of Pt nanoparticles achieved via electrochemical methods [17][18][19][20][21][22][23][24][25][26]. In situ preparation of Pt nanoparticles has been achieved via electrochemical methods, and in particular potentiostatic deposition at a fixed potential value which is sufficiently negative to assure reduction of the appropriate precursors to metallic states.…”