| Abstract: | Nitrogen-doped titanium dioxide (N/TiO2) nanophotocatalysts were successfully synthesized in the presence of environmentally benign nitrogen dopant source, guanidinium chloride, by the sol–gel method. The effect of calcination temperature (300–600 °C) on their physicochemical properties was investigated by means XRD, XPS, FESEM, HRTEM, Raman spectroscopy, UV-vis DRS, PL and BET. Moreover, their photocatalytic activities were evaluated against rhodamine B (RhB) degradation under direct sun light. Results showed that the crystal phase of spheroidal N/TiO2 nanoparticles was changed from anatase (300 °C) to rutile (600 °C) via an intermediate anatase/rutile (A/R) mixed phase (400–500 °C), and the RhB photodegradation performance was increased with the decrease of the calcination temperature. Notably, N/TiO2 prepared at 400 °C demonstrated the best degradation performance (99%) after 5 h irradiation. The enhanced performance with high photostability was mainly attributed to its higher surface area and pore volume, stronger light absorption, and lower recombination rate. Such nanomaterials have practical applications for environmental remediation. |
