X-ray photoelectron spectroscopy (XPS) measurements were taken with PHI Versaprobe spectrometer with a monochromated Al Kα source (1486.6 eV). Optical microscopy was performed using an Olympus BX53M microscope under white light illumination. Thermal imaging was performed using a thermal camera (Shot-Pro, SEEK Thermal). for each catalyst (Figure ) and the Gibbs free energy of the CO oxidation reaction as described in Equation S4.