Acid anion electrolyte effects on platinum for oxygen and hydrogen electrocatalysis

Gaurav Ashish Kamat, José A. Zamora Zeledón, G. T. Kasun Kalhara Gunasooriya, Samuel M. Dull, Joseph T. Perryman, Jens K. Nørskov, Michaela Burke Stevens*, Thomas F. Jaramillo*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

Platinum is an important material with applications in oxygen and hydrogen electrocatalysis. To better understand how its activity can be modulated through electrolyte effects in the double layer microenvironment, herein we investigate the effects of different acid anions on platinum for the oxygen reduction/evolution reaction (ORR/OER) and hydrogen evolution/oxidation reaction (HER/HOR) in pH 1 electrolytes. Experimentally, we see the ORR activity trend of HClO4 > HNO3 > H2SO4, and the OER activity trend of HClO4> HNO3 ∼ H2SO4. HER/HOR performance is similar across all three electrolytes. Notably, we demonstrate that ORR performance can be improved 4-fold in nitric acid compared to in sulfuric acid. Assessing the potential-dependent role of relative anion competitive adsorption with density functional theory, we calculate unfavorable adsorption on Pt(111) for all the anions at HER/HOR conditions while under ORR/OER conditions ClO4 binds the weakest followed by NO3 and SO42−. Our combined experimental-theoretical work highlights the importance of understanding the role of anions across a large potential range and reveals nitrate-like electrolyte microenvironments as interesting possible sulfonate alternatives to mitigate the catalyst poisoning effects of polymer membranes/ionomers in electrochemical systems. These findings help inform rational design approaches to further enhance catalyst activity via microenvironment engineering.
Original languageEnglish
Article number20
JournalCommunications Chemistry
Volume5
Number of pages10
ISSN2399-3669
DOIs
Publication statusPublished - 2022

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