Formation of crack-free nanoporous tin oxide layers via simple one-step anodic oxidation in NaOH at low applied voltages

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

“…Dendrites are still preserved, and their branches remain separated (see especially Figure 4c). In all cases, the average diameter of nanochannels within the anodic film was estimated to bẽ 60 nm what is in accordance with values previously observed for anodic SnO x formed on the Sn foil (for details see our previous works [24,44]). As can be seen in Figure 2a, no significant changes in XRD patterns of Sn foams were caused by anodization that indicates the amorphous or poorly crystalline nature of the anodic film and is consistent with our previous findings [44].…”

“…After electrodeposition, Sn foams were subjected to potentiostatic anodic oxidation in the alkaline electrolyte. All anodization conditions were developed in our previous works [24,32]; however, due to the micro/nanostructured character of foams, the process duration needs to be carefully reconsidered. In order to investigate this parameter, a series of anodizations were carried out with three different anodizing times ranging from 10 to 30 min.…”

“…Secondly, the curve recorded during anodization of the Sn foam exhibits a significantly different and unusual shape. For both types of substrates, a current density drop caused by the formation of the compact passive oxide layer is observed immediately after applying the potential and it is followed by the current rise, being an indication of the pore formation (for detailed discussion of current density shapes and particular stages of anodization, please refer to our previous works [24,32,44,45]). After about 100 s of anodization of the Sn foil, a steady-state current is reached, and no significant changes are noticeable until the end of the process.…”

“…Among diverse methods of synthesis of nanostructured tin oxides, one of the most attractive is electrochemical oxidation (anodization) of Sn because of its simplicity, low-cost, high effectiveness, and possibility of controlling and tuning the morphology of nanostructures [24,25]. Despite extensive studies on the influence of various anodizing conditions (e.g., applied potential, electrolyte composition, process duration) on the growth and morphology of porous anodic SnO x layers, which have already been performed [24][25][26][27][28][29][30][31][32], nanostructured anodic tin oxide films have been obtained mostly on tin foils [24,26,28,30,32] or smooth Sn layers electrochemically deposited on conductive supports [25,27]. To the best of our knowledge, no researches concerning possibilities of fabrication of nanoporous SnO x on micro/nano-structured metallic substrates have been reported, except the approach proposed by Wu et al [33] based on the oxidation of Sn nanowire arrays prepared using template-assisted electrodeposition.…”

Self‐Organized Arrays of SnO2 Microplates with Photocatalytic and Antimicrobial Properties

“…Lower applied voltages lead to a surface passivation by precipitation of tin oxalate , . The formation of porous tin oxide structures in alkaline solution was studied under various conditions . Schmuki and co‐workers introduced an anodization approach in an acetonitrile/water mixture‐based electrolyte containing Na 2 S and NH 4 F to obtain functional, high‐aspect ratio, ordered tin oxide films with regular nanochannel structures and top‐open pores.…”