Atomic layer deposition of TiO2-nanomembrane-based photocatalysts with enhanced performance

Abstract

In this study, TiO2 and TiO2-ZnO nanomembranes were fabricated by atomic layer deposition using the three-dimensionally porous template and their photocatalytic properties were investigated. The nanomembranes were firstly deposited onto the surface of polyurethane porous sponge templates (sacrificial templates), followed by a calcination at 500 or 800 °C. Three-dimensionally porous structures as a replica of the porous sponge templates were thus achieved. By a pulverizing process, the porous structures were broken into small pieces, which were then employed as photocatalyst. Experimental results show that the degree of crystallinity is raised by increasing of the nanomembrane thickness due to the increase of the grain size with minimizing the number of grain boundaries in the thicker nanomembrane, which is beneficial to enhance the photocatalysis efficiency. On the other hand, the photocatalytic activity can also be improved by TiO2-ZnO composite, due to lower electron-hole recombination possibility and better carrier conductivity.

TiO2 Nanomembranes Fabricated by Atomic Layer Deposition for Supercapacitor Electrode with Enhanced Capacitance

“…The NMs deposited by ALD can replicate the morphology of the original substrate (i.e., sponge) and therefore some irregular surface structures in the insets of Fig. 1 c and d may originate from the template or from the calcination process [ 37 ]. Normally, TiO 2 has three different crystal structures: anatase (tetragonal; space group, I41/amd ), brookite (orthorhombic; space group, Pcab), and rutile (tetragonal; space group, P42/mnm ) phases.…”

Atomic Layer Deposition-Derived Nanomaterials: Oxides, Transition Metal Dichalcogenides, and Metal–Organic Frameworks

“…These synthesized nanomembranes with favorable thickness, crystalline phase, and composition showed the desired performance as a supercapacitor, in printed electronics, as a lithium ion battery, ,, and as a photocatalyst. ,,, ZnO nanomembranes demonstrated their superiority for fast and long-lifespan lithium storage by providing a shortened ion diffusion length and accommodating strain. , When uniformly dispersing ZnO nanomembranes in a carbon foam matrix, ZnO nanomembranes adhered to the carbon foam framework closely (Panels (i) and (ii) of Figure a) . The synthesized anode retained 92% capacity after 700 cycles at 2 A g –1 and after 500 cycles at 5 A g –1 .…”

“…Besides the single phase nanomembrane, ALD is feasible for designing multiple-compound-layered structures by applying a multiple binary ALD process into a supercycle . As an example, TiO 2 –ZnO composite nanomembranes were synthesized by performing m cycles of the TiO 2 binary process and n cycles of the ZnO binary process . The tuning of the composition was achieved by changing the m / n ratio, the deposition sequence, and the arrangement of the sublayer stacks.…”

Assembly and Self‐Assembly of Nanomembrane Materials—From 2D to 3D

“…Vapor phase deposition is commonly used in producing nanomembrane structures. The examples are chemical vapor deposition, physical vapor deposition, atomic layer deposition, and molecular beam epitaxy, etc. In these approaches, source materials travel through reduced background pressure in the chamber and condense on the substrate to form designed materials with or without chemical reactions.…”