Interfacial Charge Transport in 1D TiO₂ Based Photoelectrodes for Photoelectrochemical Water Splitting

Abstract

1D nanostructured photoelectrodes are promising for application as photoelectrochemical (PEC) devices for solar energy conversion into hydrogen (H2) owing to the optical, structural, and electronic advantages. Titanium dioxide (TiO2) is the most investigated candidate as a photoelectrode due to its good photostability, low production cost, and eco‐friendliness. The obstacle for TiO2's practical application is the inherent wide bandgap (UV‐lights response), poor conductivity, and limited hole diffusion length. Here, a comprehensive review of the current research efforts toward the development of 1D TiO2 based photoelectrodes for heterogeneous PEC water splitting is provided along with a discussion of nanoarchitectures and energy band engineering influences on interfacial charge transfer and separation of 1D TiO2 composited with different dimensional photoactive materials. The key focus of this review is to understand the charge transfer processes at interfaces and the relationship between photogenerated charge separation and photoelectrochemical performance. It is anticipated that this review will afford enriched information on the rational designs of nanoarchitectures, doping, and heterojunction interfaces for 1D TiO2 based photoelectrodes to achieve highly efficient solar energy conversion.

Comparison of the heat-treatment effect on carrier dynamics in TiO2 thin films deposited by different methods

“…Interest in TiO 2 has arisen since it shows applications in water splitting 1,2 , photo-degradation [3][4][5] and as photoanode in photovoltaic cells 6,7 . TiO 2 has been considered an important semiconductor metal oxide (MO) because it is often used as a photocatalyst for its low cost, non-toxicity and high chemical stability 8 .…”

Modulating Surface/Interface Structure of Emerging InGaN Nanowires for Efficient Photoelectrochemical Water Splitting

“…Among many reported works, the STH efficiency is the most commonly used to estimate the capability of photoelectrodes for hydrogen generation and becomes a benchmark for the practical application of PEC water splitting system. The STH measurements should be evaluated in the following standard conditions: [30] i) Calibrating irradiation light into simulated solar Air Mass 1.5 Global (AM 1.5 G) illumination; ii) Applying two-electrode system without any external energy input except for irradiation light and electrolyte; iii) Isolating the working electrode (WE) and counter electrode (CE) to prevent the adverse reaction of the generated O 2 and H 2 . In addition, the sacrificial agents in electrolyte are avoided.…”

“…where V app is the applied potential versus reference electrode (RE). Meanwhile, the incident photo-to-current efficiency (IPCE) can be applied to evaluate the quantum efficiency of photoelectrode under the monochromatic light using Equation ( 8): [30] λ ( ) where λ and P λ are the wavelength and the power density of incident monochromatic light, respectively.…”

NiCoP/NF 1D/2D Biomimetic Architecture for Markedly Enhanced Overall Water Splitting

“…Compared to 3D MOFs derivatives, two‐dimensitonal (2D) MOFs derivatives have thinner walls, which leads to a larger specific surface area, more electron transport channels, and as well as increased abundant reaction sites for catalytic reactions [14] . For example, synthesized well‐inherited two‐dimensional (2D) ultrathin arrays of metal‐doped CoP, which displays satisfactory activity towards overall water splitting [15] . Nevertheless, the solid portions of these derived 2D structures are usually thicker than original structure, which may reduce electron transfer/penetration efficiency and the availability of active sites [16,17] .…”

“…[14] For example, synthesized well-inherited two-dimensional (2D) ultrathin arrays of metal-doped CoP, which displays satisfactory activity towards overall water splitting. [15] Nevertheless, the solid portions of these derived 2D structures are usually thicker than original structure, which may reduce electron transfer/penetration efficiency and the availability of active sites. [16,17] In addition, the utilization of one-dimensional (1D) nanowires has also been found to benefit electrolyte diffusion and mass transport during the catalytic reaction, leading to fast charge transport.…”