Titania samples containing octahedral anatase particles (OAPs) were prepared by the ultrasonication-hydrothermal process of partially proton-exchanged potassium titanate nanowires. It was found that increase in the ultrasonication time changed the product morphology, with other structural properties such as specific surface area, crystalline size, and crystallinity remaining almost constant. The results of photocatalytic activity tests for those samples suggested higher activity of a sample with higher OAP content, especially for reactions in the presence of oxygen.