“…5, and by applying the direct method, it was possible to estimate the band gap energies (Eg) of the photocatalysts (Liu & Li, 2012). The estimated Eg were as follows: 3.23 eV for W1, 3.24 eV for W1-25, 3.22 eV for W1-50, and 3.23 eV for W1-75, indicating that the estimated band gap energies have not undergone major changes, which agree with the data reported in the literature for pure TiO 2 (Martin-Somer et al, 2020;Neto et al, 2017;Resende et al, 2017). Most likely, this stems from the synthesis conditions adopted in this work, where none dopant material was added.…”