Effect of treatment at high temperatures on morphology of a carbon supported Pd catalyst investigated by X-ray diffraction and photoelectron spectroscopy aided with QUASES

•Carbon Vulcan XC-72 (Pd/C) anode catalyst for formic acid (FA) electro-oxidation.•High temperature treatment (HTT) at 200–400 °C studied by XRD and QUASES.•C incorporation, PdCx formation of x < 0.01 - ∼0.04 (200–400 °C) (XRD).•Sintering, PdOx reduction, PdOx content and overlayer thickness decrease (QUASES).•Elastic scattering correction of QUASES results improves agreement with XRD data.