Formation of TiN–Ir particle films using pulsed-laser deposition and their electrolytic properties in producing hypochlorous acid

Using sintered TiN and TiN–Ir (Ir contents: 5.9–14.2 at.%) targets, pulsed-laser deposition (PLD) was carried out to produce thin films composed of nanoparticles and particulates in the presence of nitrogen gas. The size (2–100 nm) of the produced crystalline TiN nanoparticles increased as nitrogen pressure was increased in the range from 1.33 to 1.33 × 102 Pa. At a pressure of 1.33 × 103 Pa, amorphous TiN nanoparticles combined in the form of chains. Large Ir particulates with diameters of up to 2 μm were particularly prominent in TiN–Ir films. Size distributions of the Ir particulates were dependent on ablation laser wavelength; that is, the diameter decreased at laser wavelength shortened. The TiN–Ir films with different Ir contents and morphologies on Ti substrates were evaluated as electrolysis electrodes for water disinfection. The highest current efficiency was 0.45%, which is comparable to that of conventional Ti–Pt electrodes, for a chloride-ion concentration of 9 mg dm−3.