The effect of anodizing potential and annealing conditions on the morphology, composition and photoelectrochemical activity of porous anodic tin oxide films

Hierarchical Nanoporous Sn/SnOx Systems Obtained by Anodic Oxidation of Electrochemically Deposited Sn Nanofoams

“…The wettability of anodized samples was also studied. As we recently proved, the generation of nanoporous SnO x film on a flat Sn foil significantly improves hydrophilicity of the surface [40]. As shown in insets in Figure 4a,d, the presence of porous oxide did not change the wettability of Sn foams, i.e., even after anodic oxidation, such layers remain superhydrophilic (CA < 10 • ).…”

“…Nevertheless, for several applications, including photoelectrochemical water splitting, good wettability of the nanostructured electrode is strongly desirable. Since we recently confirmed the hydrophilic nature of nanoporous SnO x electrochemically grown on the surface of Sn foil [40], it can be expected that the presence of such kind of porous oxide film can strongly affect the wetting behavior of Sn foams. However, the factors which govern the wetting behavior of these materials remain obscure.…”

“…where: Ip (λ) is photocurrent density (A•m −2 ), P(λ) is the incident power density of light (W•m −2 ) and λ is the wavelength (nm), and the resulting IPCE spectra are shown in Figure 5b. It has been proven, that annealing of anodic SnO x layers formed on the plain Sn foil not only can improve the photoresponse of anode [29,40,44] resulting in both higher photocurrents and enhanced electrode stability, but also can affect the Sn 2+ content and, in consequence, bandgap of the semiconductor [40]. For this reason, the photoresponse of annealed Sn/SnO x foams was also tested, and the obtained photocurrent spectrum is also shown in Figure 5a (black line).…”

“…30 • and 33 • , which give the evidence for the presence of the SnO crystalline phase after thermal treatment. This can be, on the one hand, the result of thermal oxidation of the remaining Sn (especially significant in case of micro/nanostructured substrate), and on the other hand, the crystallization of Sn 2+ -rich domains within the as-anodized non-stoichiometric anodic SnO x structure [29,40].…”

SnO x @β–SnO heterostructures and their enhanced photocurrent in photoelectrochemical cell

“…The phase changes of SnO 2 to Sn 3 O 4 /SnO 2 to SnO/Sn 3 O 4 were reported via changing precursor initial pH [9], but there is no discussion on the photocurrent, nor on SnO/SnO 2 related water splitting. Recently, Zaraska et al prepared porous anodic Sn 3 O 4 /SnO x films under different sets of annealing conditions and obtained a maximal photocurrent density of 30 μA cm −2 with a UV illumination light [10]. And Tian et al [11] prepared SnO and Sn 4+ -SnO nanosheets with a solvothermal method.…”