The main aim of the project is to study the effect of Nafion and Co3O4 protective layers on the properties of indium zinc sulfide (ZnIn2S4, ZIS) layers deposited on FTO glass using pulsed layer deposition (PLD) as a photoanode for photoelectrochemical water splitting. Zinc indium sulfide, as a typical member of the transition metal layered chalcogenides group, is considered a promising material for use in photoelectrochemical processes. ZIS has a narrow energy gap, which is necessary for processes with visible light. Moreover, it strongly absorbs light, is non-toxic, inexpensive and relatively easy to obtain. Unfortunately, ZnIn2S4 easily undergoes photocorrosion due to slow charge migration, easy recombination of charge carriers and slow water oxidation kinetics on the surface. Preliminary tests confirmed that despite the relatively high initial photocurrents generated, their values quickly decreased, significantly limiting the possibility of using this material in real systems. Using cocatalysts is one of the most effective methods for improving the performance of photoanodes. Considering the published papers and preliminary studies of ZIS layers deposited with PLD, Co-containing cocatalysts have the most potential. Co3O4 was chosen as the most suitable compound for the project concept. This is a commercially available compound whose performance has been confirmed for other photoanodic materials. Using Nafion as a binder to form the cocatalyst layer brings additional advantages. Nafion is known for its extremely high proton conductivity ~ 10 mS cm-1 and negligible electron conductivity. It makes it a good candidate as a barrier material between the photoanode and the electrolyte, facilitating the transport of holes generated on the photoanode to the electrolyte interface, where the water oxidation process occurs. The project involves the purchase of stirrer and heating plate costing 13000 PLN. Indirect costs will amount 12500 PLN.