Photocatalytic Water Splitting: Band-Edge Alignment & Charge Kinetics

This simulator models the microscopic mechanism inside a semiconductor photocatalyst particle suspended in water: absorbed photons generate electron-hole pairs, which must out-race recombination to reach the particle's surface and drive hydrogen and oxygen evolution. Switch between real photocatalyst materials (TiO₂ anatase, TiO₂ rutile, WO₃, CdS) or dial in custom band edges to see why the position of the conduction and valence bands relative to the water redox potentials — not just the bandgap size — decides whether a material can split water at all, and watch how defect recombination and platinum co-catalyst loading control the apparent quantum yield.