Twin-induced one-dimensional homojunctions yield high quantum efficiency for solar hydrogen generation.

Efficient charge separation is of crucial importance for the improvement of photocatalytic activity for solar hydrogen evolution. Here we report efficient photo-generated charge separation by twin-induced one-dimensional homojunctions with type-II staggered band alignment, using a ternary chalcogenate, i.e. Cd0.5Zn0.5S nanorod as a model material. The quantum efficiency of solar hydrogen evolution over this photocatalyst, without noble metal loading, reaches 62%. Unlike traditional heterojunctions, doping or combination of additional elements are not needed for the formation of this junction, which permits us to tune the band structures of semiconductors to the specific application in a more precise way. Our results highlight the power of forming long-range ordered homojunctions at the nanoscale for photocatalytic and photoelectrochemical applications.