Surface Properties of 1DTiO₂ Microrods Modified with Copper (Cu) and Nanocavities

This work deals with Cu-modified 1DTiO₂ microrods (MRs) and their surface properties. The pristine lyophilized precursor Cu_1DTiO₂, prepared by an environmentally friendly cryo-lyophilization method, was further annealed in the temperature interval from 500 to 950 °C. The microstructure of all samples was characterized by electron microscopy (SEM/EDS and HRTEM/SAED), X-ray powder diffraction (XRD), infrared spectroscopy, simultaneous DTA/TGA thermoanalytical measurement, and mass spectroscopy (MS). Special attention was paid to the surface structure and porosity. The 1D morphology of all annealed samples was preserved, but their surface roughness varied due to anatase-rutile phase transformation and the change of the nanocrystals habits due to nanocavities formation after releasing of confined ice-water. The introduction of 2 wt.% Cu as electronically active second species significantly reduced the direct bandgap of 1DTiO₂ in comparison with undoped TiO₂ and the standard Degussa TiO₂_P25. All samples were tested for their UV absorption properties and H₂ generation by PEC water splitting. We presented a detailed study on the surface characteristics of Cu doped 1DTiO₂ MRs due to gain a better idea of their photocatalytic activity.