Photoelectrochemical water splitting with nanocrystalline Zn1−xRuxO thin films

Thin films of nanocrystalline Zn1−xRuxO are deposited on ITO substrate by sol–gel. XRD and EDX analysis indicated dominant evolution of wurtzite ZnO with crystallite size in the range 26–43 nm. With no evidence of phase segregation, Ru insertion in the host lattice is probably indicated by distortion in lattice parameters and concomitant rise in microstrain and dislocation density. SEM images indicated homogenous and continuous growth of nanocrystallites. AFM images confirmed pillar like growth of crystallites along c-axis. Ru incorporation (1, 3, 5 and 7% at.) made film surface rougher, nevertheless roughness decreased with rise in Ru concentration. Ru incorporation at low concentrations significantly improved PEC response of films.

► Ru:ZnO has been explored for its possible application in PEC splitting of water.
► 3% at. Ru:ZnO (sintered at 600 °C) yielded 776 μA/cm−2 of Jsc (vs. SCE).
► This Jsc is atleast 1.5 folds higher than the current seen with Cr and Ni:ZnO [20].
► This study shows a close link between ZnO microstructures and their PEC behavior.
► Thus, nanostructured ZnO appears an attractive material for PEC application.