Synthesis and visible-light-driven photocatalytic activity of Ta4+ self-doped gray Ta2O5 nanoparticles - Gomes, Luiz E.; Silva, Marcio F.; Gonçalves, Renato Vitalino; Machado, Giovanna; Alcantara, Glaucia B.; Caires, Anderson R. L.; Wender, Heberton (Journal of Physical Chemistry C, 2018)