Enhanced Carrier Transport of N-Doped TiO₂for Photoelectrochemical Cells

Abstract

The carrier transport kinetics of the TiO 2 film doped with N (TiO 2 :N) were investigated by measuring the current and open circuit potential transients under light on/off illumination. These measurements were compared to an undoped film. The N in TiO 2 not only shifted the light absorption into a longer wavelength region (known effect) but also enhanced the carrier transport. The combination of these two effects improved the photogeneration of the electron-hole pairs and suppressed their recombination, resulting in much better photoelectrochemical performance, compared to that of the undoped TiO 2 . #

Highly Efficient Capillary Photoelectrochemical Water Splitting Using Cellulose Nanofiber‐Templated TiO2 Photoanodes

“…Among current endeavors to explore renewable energy technologies, photoelectrochemical (PEC) water splitting holds great promise for conversion of solar energy to chemical energy . Light absorption, charge separation, and appropriate interfacial redox reactions are three key aspects that lead to highly efficient solar energy conversion . Therefore, development of high‐performance PEC electrodes has been concentrated largely on engineering the band structure of photoanodes, enlarging semiconductor‐electrolyte interfacial area, and enabling rapid charge separation, collection, and transportation .…”

α-Fe2O3/Ti–Nb–Zr–O composite photoanode for enhanced photoelectrochemical water splitting

“…However, TiO 2 -based photoanodes usually have two major problems: (1) the wide band gap (3.2 eV) of TiO 2 limits the application on PEC water splitting, (2) fast recombination of excitons due to the short diffusion paths of charge carriers [4,5]. In order to improve the catalytic activity of TiO 2 , many elements (Fe, Mo, Cr, B, C, N, S and F) have been used to dope TiO 2 [6][7][8][9][10][11][12]. Recently, one dimensional nanotubular structures have aroused great interests mainly due to their high surface area and easily functionalized architecture with vectorial electro percolation pathways to reduce the recombination of electron [13].…”

Three-Dimensional High-Density Hierarchical Nanowire Architecture for High-Performance Photoelectrochemical Electrodes

“…This is a competitive value as compared to other TiO 2 -based PEC anodes. 4,10,14,20,22,23,25,26,28,29,36,37 In order to provide a visual interpretation for these performance changes, the morphology of the overcoatings was investigated by SEM. As shown in Figure 6c,d, diameters of the TiO 2 NRs were nearly unaffected after overcoating.…”

“…Photocatalyzed water splitting has received considerable attention as a clean, abundant and renewable strategy in which to address both the energy crisis and environmental concerns over the use of fossil fuels. − Efficient, stable, chemically inert, low-cost, and nontoxic photoelectrochemical (PEC) electrodes are essential to the success of water splitting. − Light absorption, charge generation and separation, and the matching of interfacial redox reactions represent the three most fundamental aspects of problems we face in this arena. − A fast interfacial charge transfer rate and suppressed electron–hole recombination are greatly desired. − Promising solutions for efficient solar-to-chemical energy conversion include avoiding charge trapping on semiconductor surfaces, increasing semiconductor-electrolyte interfacial area, and enhancing the capability for instantaneous charge collection, separation, and transport. ,,,,, Therefore, three-dimensional (3D) nanowire (NW) networks may represent ideal architectures for high-performance PEC electrodes. High-density treelike branched NW arrays provide a type of architecture that could offer long optical paths for efficient light absorption, high-quality one-dimensional (1D) conducting channels for rapid electron–hole separation and charge transport, as well as high surface areas for fast interfacial charge transfer and electrochemical reactions. , In this paper, we report on the development of a 3D high-density heterogeneous NW architecture by growing titanium dioxide (TiO 2 ) nanorods (NRs) uniformly on dense Si NW array backbones using our surface-reaction-limited pulsed chemical vapor deposition (SPCVD) technique. , Dramatic increases of photocurrent and photoelectrochemcial efficiency were obtained when the 3D NW architectures were applied as PEC anodes.…”