Investigation on nitridation processes of Sr(2)Nb(2)O(7) and SrNbO(3) to SrNbO(2)N for photoelectrochemical water splitting

The processes involved in the nitridation of Sr(2)Nb(2)O(7) and SrNbO(3) to SrNbO(2)N were assessed by varying the nitridation time, and the related effects on the physical and photoelectrochemical properties of the nitrided products were investigated. In the case of the layered perovskite-type oxide Sr(2)Nb(2)O(7), the introduction of nitrogen and the extraction of oxygen took place concurrently, leading to lattice shrinkage and a porous structure. In contrast, during nitridation of the perovskite-type oxide SrNbO(3), nitrogen was initially introduced without any loss of oxygen, which caused phase separation as a result of a lattice expansion and a charge compensation. The photoelectrochemical properties of obtained SrNbO(2)N under simulated sunlight were found to vary with the oxide precursor used and with the nitridation process.