Rotating disk electrode catalyst surface

Schmidt TJ, Gasteiger HA, Behm RJ. 1999b. Rotating disk electrode measurements on a high-surface area Pt/Vulcan carbon fuel cell catalyst. J Electrochem Soc 146 1296-1304. 

In the most common approach, a water-insoluble metaUoporphyrin is deposited on the surface of a rotating disk electrode (RDE) or on the disk of a rotating ring-disk electrode (RRDE Fig. 18.7a) as a film of poorly defined morphology, either by spontaneous adsorption from a solution of the catalyst in an organic solvent or by evaporation of an aliquot of such a solution onto the electrode. It is impossible to know the... 

UTCFC has modified the carbothermal synthesis process (U.S. Patent 4,677,092, US 4,806,515, US 5,013,618, US 4,880,711, US 4,373,014, etc.) to prepare 40 wt% ternary Pt alloy catalysts. Various high-concentration Pt catalyst systems were synthesized and the electrochemical surface area (EGA) and electrochemical activity values compared to commercially available catalysts (see Table 3). The UTCFC catalysts showed EGA and activity values comparable to the commercial catalysts. A rotating disk electrode technique for catalyst activity measurements has been developed and is currently being debugged at UTCFC. 

Electrocatalysts with a 1/8 of monolayer Pt loading on Ru nanoparticles have been synthesized by spontaneous deposition of Pt on a Ru surface, each of which have at least three times larger mass-specific activity for H2 oxidation than two commercial catalysts and a larger CO tolerance, as determined by thin film rotating disk electrode measurements. 

The transition to more realistic conditions, near fuel cell environment, is achieved using a thin-film rotating disk electrode with a practical supported catalyst. It allows obtaining kinetic parameters such as the the exchange current density and Tafel slopes, avoiding the use of complex models. This is of fundamental importance, because small catalyst particles having a significant fraction of surface atoms could behave differently compared to bulk materials. 

Shan J, Pickup PG. Characterization of pol5uner supported catalysts by cyclic voltammetry and rotating disk voltammetry. Electrochim Acta 2000 46(1) 119-25. Schmidt TJ, Gasteiger HA, Stab GD, Urban PM, Kolb DM, Behm RJ. Characterization of hi -surface-area electrocatalysts using a rotating disk electrode configuration. J Electrochem Soc 1998 145(7) 2354—8. 

Figure 13.7. Polarization curves for O2 reduction reaction on Au/Pt/C (A) and Pt/C (C) catalysts on a rotating disk electrode, before and after 30,000 potential cycles. Sweep rate 10 mV/s rotation rate 1600 rpm. Voltammetric curves for Au/Pt/C (B) and Pt/C (D) catalysts before and after 30,000 cycles sweep rates 50 and 20 mV/s, respectively. The potential cycles were from 0.6 to 1.1 V in an 02-saturated 0.1 M HCIO4 solution at room temperature. For aU electrodes, the Pt loading was 1.95 mg (or 10 nmol) on a 0.164 cm glassy carbon rotating disk electrode. The shaded area in (D) indicates the lost Pt surface area [31]. (From Zhang J, Sasaki K, Sutter E, Adzic RR. Stabilization of platinum oxygen-reduction electrocatalysts using gold clusters. Science 2007 315 220-2. Reprinted with permission from AAAS.)...

FIGURE 4-1 (a) Specific and (b) mass activities for the ORR on carbon-supported Pt catalysts, polycrystaUine Pt (shown at "Om /gp") and Pt-black catalysts (Pt surface area 5m /gpi) determined by rotating disk electrode method in Oi-saturated O.IM HQO4 at 0.9V and 60°C. Reprinted from Ref. [4] with permission from Appl. Catal. B - Environ. 

The iron complex (23) adsorbed on graphite electrode surfaces is an active catalyst for the electroreduction of both nitrite and nitric oxide to yield NH2OH and NH3, as demonstrated by rotating ring-disk electrode voltammetry experiments.341... 

U.A. Paulus, T.J. Schmidt, H.A. Gasteiger, R.J. Behm, Oxygen reduction on a high-surface area Pt/Vulcan carbon catalyst A thin-film rotating ring-disk electrode study. J. Electroanal. Chem. 2001, 495, 134-145. 

Using underpotential deposition with the redox replacement technique a novel electrochemical approach for nanoparticle-based catalyst has been designed. Here, the as-prepared Pt-coated Au nanoparticle monolayer at atomic level on the electrode surface can reduce O2 predominately by 4e to H2O, which was confirmed by rotating ring disk electrode technique (Figure 8). 

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