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Substrate selection for fundamental studies of electrocatalysts and photoelectrodes: inert potential windows in acidic, neutral, and basic electrolyte.

Benck JD, Pinaud BA, Gorlin Y, Jaramillo TF - PLoS ONE (2014)

Bottom Line: In order to help researchers with the substrate selection process, we employ a consistent experimental methodology to evaluate the electrochemical reactivity and stability of seven potential substrate materials for electrocatalyst and photoelectrode evaluation.We determine the inert potential window for each substrate/electrolyte combination and make recommendations about which materials may be most suitable for application under different experimental conditions.Furthermore, the testing methodology provides a framework for other researchers to evaluate and report the baseline activity of other substrates of interest to the broader community.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Engineering, Stanford University, Stanford, California, United States of America.

ABSTRACT
The selection of an appropriate substrate is an important initial step for many studies of electrochemically active materials. In order to help researchers with the substrate selection process, we employ a consistent experimental methodology to evaluate the electrochemical reactivity and stability of seven potential substrate materials for electrocatalyst and photoelectrode evaluation. Using cyclic voltammetry with a progressively increased scan range, we characterize three transparent conducting oxides (indium tin oxide, fluorine-doped tin oxide, and aluminum-doped zinc oxide) and four opaque conductors (gold, stainless steel 304, glassy carbon, and highly oriented pyrolytic graphite) in three different electrolytes (sulfuric acid, sodium acetate, and sodium hydroxide). We determine the inert potential window for each substrate/electrolyte combination and make recommendations about which materials may be most suitable for application under different experimental conditions. Furthermore, the testing methodology provides a framework for other researchers to evaluate and report the baseline activity of other substrates of interest to the broader community.

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Electrochemical activity and inert potential range for fluorine-doped tin oxide (FTO).Inset for each electrolyte shows polarization curves for continuous cycling within the inert potential range for a period of 2 hours.
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pone-0107942-g004: Electrochemical activity and inert potential range for fluorine-doped tin oxide (FTO).Inset for each electrolyte shows polarization curves for continuous cycling within the inert potential range for a period of 2 hours.

Mentions: The progressive cycling of FTO is shown in Figure 4. The features associated with the cycling of FTO in the cathodic region are very similar to those of ITO. In H2SO4, the sweep is featureless until a small reductive current is observed at a potential of −0.39 V vs. RHE. Upon sweeping back to positive potentials, an oxidative peak (denoted a in Figure 4) appears which also scales with the amount of reductive current drawn during progressive cycling to more negative potentials. The reductive feature (denoted b in Figure 4) only grows in after the oxidative peak is observed. These redox features are once again attributed to changes in the oxidation state of Sn. A similar evolution of peaks is observed in the case of the NaAc and NaOH electrolytes but at more negative potentials. Hydrogen evolution currents of nearly 1 mA/cm2 at potentials of −1.19 and −0.85 V vs. RHE in NaAc and NaOH, respectively, are drawn before any Sn redox features appear.


Substrate selection for fundamental studies of electrocatalysts and photoelectrodes: inert potential windows in acidic, neutral, and basic electrolyte.

Benck JD, Pinaud BA, Gorlin Y, Jaramillo TF - PLoS ONE (2014)

Electrochemical activity and inert potential range for fluorine-doped tin oxide (FTO).Inset for each electrolyte shows polarization curves for continuous cycling within the inert potential range for a period of 2 hours.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4214636&req=5

pone-0107942-g004: Electrochemical activity and inert potential range for fluorine-doped tin oxide (FTO).Inset for each electrolyte shows polarization curves for continuous cycling within the inert potential range for a period of 2 hours.
Mentions: The progressive cycling of FTO is shown in Figure 4. The features associated with the cycling of FTO in the cathodic region are very similar to those of ITO. In H2SO4, the sweep is featureless until a small reductive current is observed at a potential of −0.39 V vs. RHE. Upon sweeping back to positive potentials, an oxidative peak (denoted a in Figure 4) appears which also scales with the amount of reductive current drawn during progressive cycling to more negative potentials. The reductive feature (denoted b in Figure 4) only grows in after the oxidative peak is observed. These redox features are once again attributed to changes in the oxidation state of Sn. A similar evolution of peaks is observed in the case of the NaAc and NaOH electrolytes but at more negative potentials. Hydrogen evolution currents of nearly 1 mA/cm2 at potentials of −1.19 and −0.85 V vs. RHE in NaAc and NaOH, respectively, are drawn before any Sn redox features appear.

Bottom Line: In order to help researchers with the substrate selection process, we employ a consistent experimental methodology to evaluate the electrochemical reactivity and stability of seven potential substrate materials for electrocatalyst and photoelectrode evaluation.We determine the inert potential window for each substrate/electrolyte combination and make recommendations about which materials may be most suitable for application under different experimental conditions.Furthermore, the testing methodology provides a framework for other researchers to evaluate and report the baseline activity of other substrates of interest to the broader community.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Engineering, Stanford University, Stanford, California, United States of America.

ABSTRACT
The selection of an appropriate substrate is an important initial step for many studies of electrochemically active materials. In order to help researchers with the substrate selection process, we employ a consistent experimental methodology to evaluate the electrochemical reactivity and stability of seven potential substrate materials for electrocatalyst and photoelectrode evaluation. Using cyclic voltammetry with a progressively increased scan range, we characterize three transparent conducting oxides (indium tin oxide, fluorine-doped tin oxide, and aluminum-doped zinc oxide) and four opaque conductors (gold, stainless steel 304, glassy carbon, and highly oriented pyrolytic graphite) in three different electrolytes (sulfuric acid, sodium acetate, and sodium hydroxide). We determine the inert potential window for each substrate/electrolyte combination and make recommendations about which materials may be most suitable for application under different experimental conditions. Furthermore, the testing methodology provides a framework for other researchers to evaluate and report the baseline activity of other substrates of interest to the broader community.

Show MeSH