A voltage-dependent investigation on detachment process for free-standing crystalline TiO2 nanotube membranes

摘要: TiO2 nanotube (TNT) arrays have attracted considerable scientific interests because of their photoelectric properties and technological importance for diverse applications as solar cells [1–4], photocatalysis [5–7], gas sensors [8], hydrogen generation from water splitting [6], composite nano-membranes [9, 10]. Among various synthesis methods, electrochemical anodization is an excellent approach to fabricate TNT due its simplicity, low cost, tunable morphology [11]. However, the nature as-prepared membrane adhered on opaque Ti foil restricts feasibility such tube filling 10], biofiltration, flow-through photocatalytic reactions [5], front illumination in [2–4]. After detachment substrate, free-standing membranes show high performance absence a blocking layer [2, 4]. The can be directly used or attached foreign substrates above applications. So far, different techniques been proposed preparing substrates, including ultrasonic solvent evaporation [12, 13], chemically assisted delamination [6, 14–16], selective metal dissolution [5, 17], voltage transition at end [18–22]. Generally speaking, these processes fabricated amorphous fragile membranes. characteristic hampered crystallized desirable practical devices. To get membranes, attempts between desired crystalline substrate [3], adjusting electrolyte temperature multi-step anodic [23] also explored. success former resolvability materials, while mechanical stability etching contrast layers account latter’s detachment. Nevertheless, fabrication large-area still challenge. In this article, handy experimental procedure was reported concept outlined Fig. 1 (1–4). ordered are firstly under optimized parameters, after annealing followed by second (detachment) step, detached without any cracks. This method reliable technique fabricating needs complicated dangerous chemicals. At same time, previous studies, we systematically investigated effects process