Soft X-ray and electron spectroscopy to determine the electronic structure of materials for photoelectrochemical hydrogen production

► Soft X-ray and electron spectroscopies were used to study materials for photoelectrochemical water splitting. ► These spectroscopies provide detailed information on the chemical and electronic structure of the investigated materials. ► Positions of the conduction band minimum and valence band maximum of WO3 and WO3:Mo were determined. ► Surface instabilities of ZnO:Zn3N2 films were identified and investigated in detail. ► It is shown how these spectroscopies can be used to study materials in an in situ fashion, e.g., in an electrolyte.