The Challenge of Water Splitting in View of Photosynthetic Reality and of Research Trends Theoretical Design of PEC Materials Computational Screening of Light-absorbing Materials for Photoelectrochemical Water Splitting Unravelling the Charge Transfer Mechanism in Water Splitting Hematite Photoanodes Rate Law Analysis of Water Splitting Photoelectrodes Emerging Semiconductor Oxides for Direct Solar Water Splitting Particulate Photocatalyst Sheets for Efficient and Scalable Water Splitting Applications of Bipolar Membranes for Electrochemical and Photoelectrochemical Water Splitting Modelling-derived Design Guidelines for photoelectrochemical Devices Technoeconomic Analysis of PEC Water Splitting at Various Scales