Semiconductor hetero-nanostructures are of great interest for practical use. In this presentation, a novel approach to production of CuO|CuFe2O4 core-shell structure by thermal conversion of CuFe Prussian Blue Analogues will be demonstrated. It represents a new family of photocatalysts that can be used as photoelectrodes able to produce hydrogen under broad spectrum of the visible light. The outstanding photoelectrochemical properties of the photocathodes of CuO|CuFe2O4 have been studied with use of combinatory photo-electrochemical instrumental techniques which proved the electrodes were stable over the whole water photolysis run under relatively positive potentials. Their outstanding performance have been explained by coupling of two charge transfer mechanisms occurring in core-shell architectures. Then, the CuO:Zn nanostructures, in which the photoelectrochemical properties were governed by Fermi level pinning of Zn ions would be presented as well. The implementation of Zn ions enlarged the space charge region and triggered electron availability for the photolysis of water which is unusual for p-type semiconductors. Furthermore, the excellent crystallinity, high surface area, and adhesion to the FTO remarkably improved the photocatalytic activity of the CuO:Zn thin film with cathodic photocurrent of 4 mAcm-2 and a quantum efficiency of 35%, making it promising for hydrogen production.