The direct conversion of solar energy by means of photoelectrocatalytic processes, such as hydrogen generation via photoelectrochemical water splitting or photo-oxidation of biomasses into higher value chemical products, represents an important pillar of the clean energy transition. Metal oxide semiconductors are the materials of choice for the fabrication of efficient photoanodes for sun-driven oxidation in a photoelectrochemical cell [1]. The pathway that leads from the photoexcitation of electron-hole pairs to the production of the energy carrier is particularly complex and requires the optimization of several materials-related factors, particularly broadband light harvesting, charge transport toward the semiconductor-electrolyte interface, and charge transfer to reactive species, generally assisted by catalysts deposited at the photoelectrode surface. Therefore, the metal oxide semiconductors must be at the same time …