The primary research objective of the TWOB project is to systematically optimize electrocatalysts and semiconducting photoelectrodes for grid-independent, tandem cell-based photoelectrochemical water splitting. The components are fabricated using sol-gel dip-coating with soft templating by evaporation induced self-assembly of co-block-polymers. An innovative synthesis allowing for precise tailoring of the physicochemical properties of thin films is developed to produce high entropy oxides specifically designed for use as electrocatalysts in the oxygen evolution reaction.