Merging operando and computational X-ray spectroscopies to study the oxygen evolution reaction

The combination of operando and computational X-ray spectroscopies has shown promise for building accurate models of active catalyst surfaces. Operando spectroscopy captures metastable active surfaces and computational spectroscopy uses this information to aid in building models for first principles reaction simulations. Herein, we review recent efforts and outline future opportunities to study the oxygen evolution reaction (OER) by combining operando spectroscopies and first principles modeling. We begin by showcasing how explicit simulation of operando-collected spectra has helped validate an OER mechanism over Ir-based catalysts involving electron-deficient oxygen, or OI−. We continue by reviewing efforts on 3d transition metal (TM) oxyhydroxides, where operando studies again suggest OI− is critical. While for these materials, changes in OI− coverage have been argued to cause qualitative mechanistic differences, comparative operando and computational spectroscopic studies are still lacking. We close by outlining how such comparative studies would aid in testing mechanistic claims on 3d TM oxyhydroxides. •Operando spectroscopy offers insight into active electrocatalytic surfaces.•Direct simulation of spectra allows validation of spectral assignments.•Combining operando and computational spectroscopy leads to mechanistic understanding.•Spectroscopy reveals importance of electron-deficient oxygen in OER catalysts.