“…For photoanodes based on anodically generated nanoporous tin oxide films, numerous challenges have to be overcome, from choosing appropriate electrosynthesis conditions for obtaining continuous nanostructures [ 15 ] to non-stoichiometric compositions of this kind of film [ 12 , 14 ]. Different strategies, including controlled thermal treatment [ 12 , 14 ], crystallization in water [ 16 , 17 ], and decoration with other semiconductors [ 18 , 19 , 20 ], have already been proposed to optimize the photoelectrochemical performance of tin oxide films. Among them, the latter approach, based on the deposition of different narrow band gap semiconductors on the tin oxide nanostructures, is considered especially promising since it results in enhanced absorption of the visible light and facilitates the charge carriers’ separation due to the favorable band alignment.…”