Impact of calcination of hydrothermally synthesized TiO₂ nanowires on their photocatalytic efficiency

The phase transformations of hydrothermally prepared H₂Ti₃O₇ nanowires (NWs) upon calcination at different temperatures were addressed to interpret the impact of H₂Ti₃O₇ NWs crystallization on their photocatalytic performance for resorcinol photodegradation under UV illumination. Bicrystalline brookite/anatase NWs were obtained by calcination at 800 °C, which indicated a superior photocatalyst compared with rutile/brookite NWs or TiO₂(B)/anatase NWs as well as commercial P-25 photocatalysts. The brookite/anatase NWs photocatalyst exhibited high photocatalytic efficiency up to 99% owing to its long charge transfer channels and high resorcinol adsorption capacity, while the commercial P-25 photocatalyst is 72% within 3 h. The rate constant k (min⁻¹) value of brookite/anatase heterostructure NWs is greater than that of TiO₂(B)/anatase NWs and commercial P-25 for 5.6 and 2 times, respectively.