Investigation of the chemical stability of different Cr(VI) based compounds during regular X-ray photoelectron spectroscopy measurements

Chromium compounds are of high importance for industrial applications, but due to their hazardous nature Cr(VI) species are subjected to strict regulations. XPS performed on these materials provides promising potential to identify the involved chemical states. However, hexavalent chromium is known to suffer degradation by decomposition, so the influence of standard XPS measurements, using a modern system with monochromatic X-rays and a dual flood gun, on the chemical stability of several Cr(VI) compounds was investigated in depth. Degradation of varying intensity is shown to be mainly induced by the dual flood gun instead of the expected photoreduction by X-rays.