Branched TiO₂ Nanorods for Photoelectrochemical Hydrogen Production

Abstract

We report a hierarchically branched TiO(2) nanorod structure that serves as a model architecture for efficient photoelectrochemical devices as it simultaneously offers a large contact area with the electrolyte, excellent light-trapping characteristics, and a highly conductive pathway for charge carrier collection. Under Xenon lamp illumination (UV spectrum matched to AM 1.5G, 88 mW/cm(2) total power density), the branched TiO(2) nanorod array produces a photocurrent density of 0.83 mA/cm(2) at 0.8 V versus reversible hydrogen electrode (RHE). The incident photon-to-current conversion efficiency reaches 67% at 380 nm with an applied bias of 0.6 V versus RHE, nearly two times higher than the bare nanorods without branches. The branches improve efficiency by means of (i) improved charge separation and transport within the branches due to their small diameters, and (ii) a 4-fold increase in surface area which facilitates the hole transfer at the TiO(2)/electrolyte interface.

Codoping titanium dioxide nanowires with tungsten and carbon for enhanced photoelectrochemical performance

“…1. First, rutile TiO 2 NWs with an average length of 2.8 mm and diameter of 100 nm are grown on fluorine-doped tin oxide (FTO) glass substrates by the hydrothermal method 34 , and the W-dopant precursor solution is prepared separately by the sol-gel method (see Methods section). Second, the TiO 2 NWs are dip-coated with the W-precursor solution (0.05 M) and then dried by air blowing, which leaves a uniform thin layer of W precursor on the surface of TiO 2 NWs.…”

“…The pristine TiO 2 NW arrays were synthesized on TiO 2 nanoparticle-coated FTO substrates using the hydrothermal method, and the details were reported in our previous work 34 . Briefly, for a typical synthesis, 0.6 ml of titanium (IV) butoxide (Aldrich Chemicals, 97%) was added into 50 ml of an aqueous HCl solution (25 ml of deionized (DI) water þ 25 ml of concentrated HCl (38%)) under magnetic stirring.…”

Enhanced photoelectrochemical and photocatalytic activities of CdS nanowires by surface modification with MoS2 nanosheets

“…Hydrogen production by solar water splitting with semiconductor photocatalysts is a promising technology based on renewable resources [1,2]. Since the first report on water splitting by Fujishima and Honda, TiO 2 has been extensively investigated as an excellent photocatalyst due to its good stability, non-toxicity, low cost and high photocatalytic activity under UV light irradiation [3][4][5]. However, TiO 2 can only absorb UV light that makes up approximately 5% of sunlight, resulting in low light utilization efficiency [6].…”

Perspective—A Brief Perspective on the Fabrication of Hierarchical Nanostructure for Solar Water Splitting Photoelectrochemical Cells

“…Moreover, the nanostructured materials own minimized defects and shortened migration distance for electrons/holes, which decreases electron-hole recombination and eventually leads high photoresponse efficiency. 5 Nanomaterials were engineered as various shapes and structures such as thin film, 6 porous frameworks, 7,8 nature-mimicked branched systems 9,10 and hierarchical structures 11,12 to obtain maximize surface areas. Among the various structures, the hierarchical metal oxide nanostructure has been broadly studied for the electrochemical applications due to a simple structure form as well as a capability of modulation for the electrical property.…”