Determination of Hydrogen Oxidation Reaction Mechanism Based on Pt−Had Energetics in Alkaline Electrolyte

Abstract

The understanding of the sluggish hydrogen oxidation reaction (HOR) kinetics in alkaline electrolyte is crucial for designing high performance electrocatalysts. Here, we report a clear and convincing result on this problem by investigating the relationship between the HOR kinetics and Pt-adsorbate energetics. Using electrochemical analysis for well-modified Pt surfaces with distinct Pt-adsorbate interactions, we establish a clear trend in activity for HOR in alkaline electrolyte, that is, the activity changes in the order Au@Pt < Pt < Pd@Pt < Ru@Pt. A decisive role of Pt−Had energetics in the HOR kinetics on Pt surfaces is determined, while no favorable effects of Pt−OHad energetics in the HOR kinetics were found. The nature of strong Pt−Had interaction for Pt/C catalyst in alkaline electrolyte is revealed by in-situ X-ray absorption near-edge structure (XANES) analysis. These insights play an important role for better understanding the mechanism and structure sensitivity for Pt catalyzed hydrogen oxidation reactions.