The role of synthesis conditions for structural defects and lattice strain in β-TaON and their effect on photo- and photoelectrocatalysis

摘要： The importance of the synthesis conditions on the structural and photocatalytic properties of tantalum oxide nitride was investigated by comparing two variants of phase-pure β-TaON obtained from application of two different synthesis routes, leading to one unstrained and one heavily anisotropically microstrained β-TaON as shown by XRD-based Rietveld refinement. HRTEM images reveal the origin of the strain to be lattice defects such as stacking faults. The strained β-TaON was found to be the clearly less active semiconductor in photochemical and photoelectrochemical water oxidation. The lattice defects are assumed to act as charge carrier traps hindering the photo-generated holes to be displaced to the reaction sites at the surface.