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

doi:10.1038/s42004-022-00635-1

Acid anion electrolyte effects on platinum for oxygen and hydrogen electrocatalysis

Commun Chem. 2022 Feb 18;5(1):20. doi: 10.1038/s42004-022-00635-1.

Authors

Gaurav Ashish Kamat^#^{1

2}, José A Zamora Zeledón^#^{1

2}, G T Kasun Kalhara Gunasooriya³, Samuel M Dull^{1

2}, Joseph T Perryman^{1

2}, Jens K Nørskov³, Michaela Burke Stevens^{4

5}, Thomas F Jaramillo^{6

7}

Affiliations

¹ Department of Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, CA, 94305, USA.
² SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.
³ Catalysis Theory Center, Department of Physics, Technical University of Denmark, 2800, Kongens Lyngby, Denmark.
⁴ Department of Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, CA, 94305, USA. mburkes@stanford.edu.
⁵ SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA. mburkes@stanford.edu.
⁶ Department of Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, CA, 94305, USA. jaramillo@stanford.edu.
⁷ SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA. jaramillo@stanford.edu.

^# Contributed equally.

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 [Formula: see text] 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 [Formula: see text] binds the weakest followed by [Formula: see text] and [Formula: see text]. 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.