Adaptive semiconductor/electrocatalyst junctions in water-splitting photoanodes

Photoelectrochemical water-splitting devices require integrating electrocatalysts with light-absorbing semiconductors, but understanding charge-transfer processes at interfaces has proved difficult. Ion-permeable electrocatalysts deposited onto TiO2 photoelectrodes now result in adaptive semiconductor/electrocatalyst junctions where both the effective interface barrier height and the photovoltage output change depending on the oxidation state of the electrocatalyst.