Among the various strategies proposed for enhancing the photoelectrochemical (PEC) performance of state-of-the-art photoelectrodes, the construction of heterostructures based on semiconductors and co-catalysts is widely acknowledged as one of the most versatile and reliable. This approach is often associated with higher quantum efficiency for photoinduced redox processes, due to improved interfacial charge transfer dynamics, and reduced degradation due to photocorrosion, as the photoinduced charge is less susceptible to this less competitive pathway. However, numerous studies [1-3] have demonstrated that this simplistic view conceals a much more complex microscopic nature, often significantly dependent on the specific characteristics of the interfaces. Therefore, understanding the redox dynamics in such complex systems is essential to direct the carriers along the desired pathways. Several indirect …