Free energy difference to create the M-OH intermediate of the oxygen evolution reaction by time-resolved optical spectroscopy

• Published in: Nature materials Vol. 21; no. 1; pp. 88 - 94
• Main Authors: Vinogradov, Ilya, Singh, Suryansh, Lyle, Hanna, Paolino, Michael, Mandal, Aritra, Rossmeisl, Jan, Cuk, Tanja
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.01.2022; Nature Publishing Group; Springer Nature - Nature Publishing Group
• Subjects: 140/125; 639/638/440/949; 639/638/77/886; Binding; Biomaterials; Catalytic activity; Chemistry and Materials Science; Condensed Matter Physics; Electron transfer; Free energy; Hydroxylation; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Kinetics; Materials Science; Nanotechnology; Optical and Electronic Materials; Oxidation; Oxidation-Reduction; Oxygen; Oxygen - chemistry; Oxygen - metabolism; Oxygen evolution reactions; Spectra; Spectroscopy; Spectrum Analysis; Strontium titanates; Surface reactions; Thermodynamics
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/s41563-021-01118-9

Theoretical descriptors differentiate the catalytic activity of materials for the oxygen evolution reaction by the strength of oxygen binding in the reactive intermediate created upon electron transfer. Recently, time-resolved spectroscopy of a photo-electrochemically driven oxygen evolution reaction followed the vibrational and optical spectra of this intermediate, denoted M-OH * . However, these inherently kinetic experiments have not been connected to the relevant thermodynamic quantities. Here we discover that picosecond optical spectra of the Ti-OH * population on lightly doped SrTiO 3 are ordered by the surface hydroxylation. A Langmuir isotherm as a function of pH extracts an effective equilibrium constant relatable to the free energy difference of the first oxygen evolution reaction step. Thus, time-resolved spectroscopy of the catalytic surface reveals both kinetic and energetic information of elementary reaction steps, which provides a critical new connection between theory and experiment by which to tailor the pathway of water oxidation and other surface reactions. Theoretical descriptors differentiate catalytic activity for oxygen evolution reaction by the strength of oxygen binding in the reactive intermediate created upon electron transfer. Picosecond optical spectra of the Ti-OH* population on doped SrTiO 3 are now shown to be ordered by surface hydroxylation.