Nature-Inspired Tree-Like TiO₂ Architecture: A 3D Platform for the Assembly of CdS and Reduced Graphene Oxide for Photoelectrochemical Processes

Abstract

A nature-inspired 'tree'-like 3D hierarchical titania/TiO 2 architecture was prepared as a façade to strategically assemble reduced graphene oxide/RGO (a facile charge transporter) and cadmium sulfide/CdS (a visible light harvester) is presented for the first time. The core 3D TiO 2 heterostructure was prepared using a TiCl 3 mediated surface treatment of titania nanorods on fluorine-doped tin oxide (FTO) coated glass-slides. The performance of the 3D TiO 2 , which varies as a function of the treatment time, was first examined to achieve optimal photoelectrochemical response.Subsequently, the architecture was tested for its (i) theoretical water-splitting potential and (ii) ability to immobilize chalcogenide nonocrystals (CdS) with and without RGO.The best 'applied bias to photoconversion efficiency' (% ABPE) was noted to be 0.36% (-0.15 V versus Ag/AgCl) for the TiO 2 architecture. A 140% increase with CdS deposition on the branched TiO 2 indicated the structures' ability to effectively immobilize the chalcogenide. The effect of RGO on the photoelectrochemical response was explored and an optimum loading (1 mg.mL -1 ) of RGO was noted to boost the photoresponse by an additional 150% compared to 'CdS-only' photoanodes. Further, stability analysis performed over 3h showed that the presence of RGO significantly delays CdS corrosion-driven deactivation. Finally, the fundamental insights on the impact of RGO in the 3D TiO 2 /RGO/CdS photoanode and its effect on the charge transportation mechanism was examined using electrochemical impedance spectroscopy.

Light‐Driven Sustainable Hydrogen Production Utilizing TiO2 Nanostructures: A Review

“…Common and effective route to enhance the spe cific surface is structuring layers with various nanostructures on TiO 2 . [111] Tang Pds/TiO 2 Anatase TiO 2 nanoparticles Successive ionic layer adsorption and reaction method [189] Au/Ag/TiO 2 NWs Commercial anatase TiO 2 particles Hydrothermal and photodeposition [190] g-C 3 N 4 /G/TiO 2 TiO 2 paste Self-assembly photochemical reduction [191] Cds/TiO 2 TiO 2 NWs Successive ionic layer adsorption and reaction method [192] N/TiO 2 NRs TiO 2 NWs Hydrothermal method [193] Cds/TiO 2 FTO-coated glass slides One-step electrodeposition technique [194] CdSe/TiO 2 FTO-coated glass Electrospinning pyrolysis and chemical bath deposition [195] Al(H 2 PO 4 ) 3 /TiO 2 Titanium fluoride Spray method [196] Ag/TiO 2−x FTO substrates Photochemical reduction process and postannealing [197] BiVO 4 /TiO 2−x Al(H 2 PO 4 ) 3 Two-step hydrothermal [198] ZnO/TiO 2 TiO 2−x Sol-gel deposition and hydrothermal [199] RGO/Ag 2 S/TiO 2 TiO 2−x Hydrothermal and ionexchange [200] RGOT aerogel ITO One-step hydrothermal [201] ZnSe/Au/TiO 2 NTs GO Two-step anodization, microwave-assisted chemical reduction and in situ deposition [202] Bi (Figure 10k,l). Still problems like accuracy controlling of the size of particles, connectivity, and distribu tion between the interfaces of NPs and TiO 2 NBs remain set tled.…”

Hierarchical 3D TiO2 Nanotube Arrays Sensitized by Graphene Oxide and ZnxCdyS for High Performance Photoelectrochemical Applications

“…These efforts include: (1) Optimization of the structure of photoelectrocatalyst to provide larger active surface areas. An example of this is the transformation of a 1D nanorod‐like TiO 2 to a 3D tree‐like branched TiO 2 to improve the photoelectrocatalytic activity by an increase of the surface area . Another example is the development of bifacial electrode, such as Ni–Sb–SnO 2 /TiO 2 on titanium foil.…”

“…An example of this is the transformation of a 1D nanorod-like TiO 2 to a 3D tree-like branched TiO 2 to improve the photoelectrocatalytic activity by an increase of the surface area. [15] Another example is the development of bifacial electrode, such as Ni-Sb-SnO 2 /TiO 2 on titanium foil. The composites have been used to treat wastewater through reactions of electrochemically generated ozone and photoelectrochemically generated hydroxyl radicals formed on Ni-Sb-SnO 2 and TiO 2 , respectively.…”

Ag Nanoparticles Located on Three-Dimensional Pine Tree-Like Hierarchical TiO2 Nanotube Array Films as High-Efficiency Plasmonic Photocatalysts

“…Nevertheless, the drawback of the low surface-to-volume ratio of one-dimensional nanostructure results to a low photocatalytic activity. Recently, researchers have been enthusiastically dedicated to develop three-dimensional nanostructures such as nanoflowers and nanotrees for application in photocatalysis [25–28]. Compared with zero-dimensional NPs and one-dimensional nanowires, the three-dimensional nanostructure offers the advantage of a large surface area that increases dye loading.…”