The proposal is built on the core idea to use an ensemble of multiple level self-organization processes to create a next generation photocatalytic platform that provides unprecedented property and reactivity control. As a main output, the project will yield a novel highly precise combined catalyst/photocatalyst assembly to: 1) provide a massive step ahead in photocatalytic applications such as direct solar hydrogen generation, pollution degradation (incl. CO2 decomposition), N2 fixation, or photocatalytic organic synthesis. It will drastically enhance efficiency and selectivity of photocatalytic reactions, and enable a high number of organic synthetic reactions to be carried out economically (and ecologically) via combined catalytic/photocatalytic pathways. Even more, it will establish an entirely new generation of “100% depoisoning”, anti-aggregation catalysts with substantially enhanced catalyst life-time. For this, a series of self-assembly processes on the mesoscale will be used to create highly uniform arrays of single-catalyst-particle-in-a-single-TiO2-cavity; target is a 100% reliable placement of a single <10 nm particle in a 10 nm cavity. Thus catalytic features of, for example Pt nanoparticles, can ideally interact with the photocatalytic properties of a TiO2 cavity. The cavity will be optimized for optical and electronic properties by doping and band-gap engineering; the geometry will be tuned to the range of a few nm.. This nanoscopic design yields to a radical change in the controllability of length and time-scales (reactant, charge carrier and ionic transport in the substrate) in combined photocatalytic/catalytic reactions. It is of key importance that all nanoscale assembly principles used in this work are scalable and allow to create square meters of nanoscopically ordered catalyst surfaces. We target to demonstrate the feasibility of the implementation of the nanoscale principles in a prototype macroscopic reactor.