Co-effect of perchlorate anions and hydrated protons on the electrochemical formation of Adams’ catalyst

Abstract

The structure and morphology of oxide on the metal electrodes are strongly linked with the activity and stability of the electrocatalysts. Herein, the novel co-effect of anion and hydrated proton on structure of PtO₂ formation is observed during the oxidation of water on Pt(100) preferentially oriented nanoparticles with in situ Raman spectroscopy and XPS. Higher concentrations (≥1.5 M) of non-specifically adsorbed perchlorate in 0.1 M perchloric acid solution facilitated the formation of crystalline α−PtO₂ during the electro−oxidation of Pt(100), and no crystalline α−PtO₂ was obtained without acid. Higher acidity electrolyte solution favors the formation of crystalline α–PtO₂, indicating that proton plays a key role since specifically adsorbed sulfate without sulfuric acid did not lead to the formation of crystalline α–PtO₂. A model containing anions, protons, and water molecules co-adsorbed on the Pt surface is constructed during density functional theory (DFT) calculations, which well explains the formation of crystalline α–PtO₂ depending on anion and proton. The study findings provide an alternate approach for environmentally friendly and controllable preparation of Adams’ catalyst and an atomic–level understanding of oxide formation on Pt electrodes, which is essential for developing the next–generation electro-catalyst with exceptional performance and stability.