As an abundant and environmentally friendly resource, solar energy has the potential to satisfy the continuously growing energy demands worldwide. Over recent decades, numerous methodologies for taking advantage of solar power have emerged, each displaying diverse technological advancements. Among these approaches, one remarkable technique involves the absorption of solar energy and storing it within the chemical bonds of a solar fuel akin to a man-made photosynthesis system. The process of converting solar energy into a chemical fuel within a solid-state device enables a direct utilization of solar energy to drive redox processes. In this configuration, the semiconductor's key role involves absorbing incident photons, creating electron-hole pairs, and easing their separation and transportation. Depending on the application, the semiconductor can be employed as particles ranging from micrometer to nanometer dimensions in a solution or as a photoelectrode. The latter setup typically involves a transparent and conducting oxide material with the semiconductor deposited as a thin film. To accomplish practical-scale photoelectrochemical (PEC) reactions, the photoelectrode should comprise of low-cost as well as abundant and non-toxic materials. Semiconducting transition metal oxides provide a wide array of electronic properties, enabling the possibility of customizing each electrode's band gap and absolute energy level alignment according to the specific electrochemical requirements.