Tanja Cuk*, Michael Paolino,听Suryansh Singh, James Stewart, Xihan Chen, and听Ilya Vinogradov
ACS Catalysis 2024, 14, 9901 DOI:听
Oxygen evolution catalysis fuels the planet through photosynthesis and is a primary means for hydrogen storage in energy technologies. Yet the detection of intermediates of the oxygen evolution reaction (OER) central to the catalytic mechanism has been an ongoing challenge. This tutorial and minireview covers the relevance of ultrafast electronic and vibrational spectroscopy of the electrochemical transformations of a metal-oxide surface undergoing OER. Here, we highlight the ultrafast trigger and probes of the electron-doped SrTiO3/electrolyte as the primary example in which light probes across the electromagnetic spectrum have detected intermediate forms. We compare the results to other early transition-metal-oxide surfaces when they exist for select probes and longer timescales. The first part covers how the catalytic reaction is triggered by ultrafast light pulses, describing the semiconducting depletion and electrolyte Helmholtz layers. The second part covers the detection of the intermediates that occur upon electron and proton transfer from an adsorbed water species by transient spectroscopy. Their detection by a broadband visible probe, a mid-infrared evanescent wave, and a coherent acoustic wave respectively targets electronic states, vibrational levels, and lattice strain respectively. One of the aims is a tutorial on how these measurements are made and to what extent they allow for the interpretation of experimental spectra by intermediate configurations predicted by theory. Another aim is to describe what these experiments directly recommend in terms of future efforts to visualize the OER intermediates and their dynamics.