Hierarchically Self-assembled Super Structural TiO₂ Microspheres: Enhanced Excitonic Efficiency as Photocatalyst and Photoanode Material

Abstract

Complex three-dimensional (3-D) super structural TiO₂ architectures with controlled shape and size were synthesized by a facile hydrothermal synthesis route by using titanium tetrachloride (TiCl₄) as the metal precursor and hydrochloric acid (HCl)/ammonium chloride (NH₄Cl) as the mineralizer/structure directing agent. Several interesting hierarchical architectures like: (i) nanoparticles assembled spheres (NPAS), (ii) nanowires assembled spheres (NWAS), (iii) nanorods assembled spheres (NRAS), and (iv) nanosheets assembled spheres (NSAS) were achieved by the controlled variation of crystal structure modifier. The synthesized materials were characterised in detail by different analytical techniques and the findings are consistent. To demonstrate the superior performances of the as prepared materials the photocatalytic and photo-voltaic performances were investigated. The results demonstrate that these synthesized materials exhibits enhanced photocatalytic activity (efficiency is ~ 91%) towards the degradation of RhB and as a photoanode in DSSCs the maximum energy conversion efficiency is ~5%, attributed primarily to the unique hierarchical mesoporous structure of the TiO₂ architectures.