Comment on "Flat band potential determination: avoiding the pitfalls" by A. Hankin, F. E. Bedoya-Lora, J. C. Alexander, A. Regoutz and G. H. Kelsall, J. Mater. Chem. A, 2019, 7, 26162

In this comment, it is shown that the work published by Hankin et al. [Hankin et al., J. Mater. Chem. A, 2019, 7, 26162-26176], while mostly timely and appropriate, present two mistakes that are discussed in detail. First, the determination of flat band potentials through a Mott-Schottky analysis is in principle not affected by the existence of a real surface area substantially larger than the geometric surface area and, second, the Gartnet-Butler model may not be applicable for electrodes with high values of the absorption coefficient and low dopant density values.