The development of new types of energy generation devices is promoted by increasing public awareness that the Earth's oil reserves could run out during this century. As the energy needs of the planet are likely to double within the next 50 years, the stage is set for a major energy shortage, unless renewable energy can cover the substantial deficit left by fossil fuels. Photoelectrochemical (PEC) solar water splitting has become a central research theme for more than four decades, still, their efficiencies remain low. Despite extensive efforts devoted to modifying photoelectrodes through various bandgap and catalysis engineering, the efficient methodologies for charge transfer at electrode/electrolyte interface remain underdeveloped. In this seminar, I will introduce various unique methods to increase light harvesting efficiency to generate hydrogen from solar light by applying disordered engineering to metal oxide materials. Especially, high efficiency TiO2, WO3, and BiVO4 photoanodes with the modification and charge transfer across the electrode/electrolyte interface will be presented.