Comment on “Molten Salt Synthesis of Bi2WO6 Powders and its Visible-Light Photocatalytic Activity” in Materials Research. 2019; 22(5): e20190311

Abstract

Recently, Dai et al. published a paper in Research Materials 2019; 22(5): e20190311. They have investigated the visible-light photocatalytic activity of the synthesized Bi 2 WO 6 powders 1 . In the context of determining of band gap energy based on diffuse reflectance measurements, the cited authors make some mistakes, which are clarified in the present letter.

Use and misuse of the Kubelka-Munk function to obtain the band gap energy from diffuse reflectance measurements

“…However, in a number of papers published recently, including some in prestigious journals in the field of Materials Science, some inconsistencies have been detected when the subject matter is the K-M model and the so-called Tauc plot [17][18][19]. Specifically, the most serious problem consists in determining of the band gap energy directly from the plot of the Kubelka-Munk function versus incident photon energy [20][21][22][23].…”