Design of a Highly Efficient Photoelectrolytic Cell for Hydrogen Generation by Water Splitting:  Application of TiO_2-xC_x Nanotubes as a Photoanode and Pt/TiO₂ Nanotubes as a Cathode

Abstract

This paper describes the design of a photoelectrochemical (PEC) cell using carbon-doped titanium dioxide (TiO2 - x C x ) nanotube arrays as the photoanode and platinum, Pt nanoparticles incorporated in TiO2 (titania) nanotube arrays, as the cathode. The PEC cell is found to be highly efficient (i.e., gives good photocurrent at a low external bias, j p = 2.5−2.8 mA/cm2 at −0.4 VAg/AgCl), inexpensive (only 0.4 wt % Pt on TiO2), and robust (continuously run for 80 h without affecting the photocurrent) for hydrogen generation by water splitting under the illumination of simulated one sun intensity. The synthesis of the photoanode is carried out by the sonoelectrochemical anodization technique using aqueous ethylene glycol and ammonium fluoride solution. This anodization process gives self-organized hexagonally ordered TiO2 nanotube arrays with a wide range of nanotube structure, which possess good uniformity and conformability. As-synthesized titania nanotubes are annealed under reducing atmosphere (H2), which converts the amorphous nanotube arrays to photoactive anatase phase as well as it helps in doping of the carbon (from the reduction of ethylene glycol) to give the TiO2- x C x type photoanode. The cathode material is prepared by synthesizing Pt nanoparticles (by reduction of a Pt salt to Pt(0)) into the titania nanotubular arrays by the incipient wetness method. Various characterization techniques, viz., field emission scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, electron diffraction, and glancing angle X-ray diffraction, etc., are used to study the morphology, phase, band gap, and doping of the nanotubes.

Growth of TiO2 nanotube arrays with simultaneous Au nanoparticles impregnation: photocatalysts for hydrogen production

“…3 In general, anodic TiO 2 NTs photocatalytic activity enhancement is also achieved by metal/non-metal ion doping, sensitization with lower band gap semiconductors and supported metal NPs. Ionic doping could be performed by choosing the appropriate electrolyte solution 15,16 (especially for anionic doping), performing the thermal annealing crystallization, 17 anodizing metal alloys, 18,19 or by ion implantation. 20,21 Other methods involve impregnation of pre-formed materials.…”

“…RBS analyses were conducted using alpha particles accelerated to 1 MeV (normal incidence and 15 o detection), allowing the quantification of the gold present in the nanotubes and providing an approximate Au depth profile. Au quantification was carried out by comparison with a standard reference that consisted of an Au-free TiO 2 NTs array implanted with 1×10 16 Au atoms cm -2 .…”

Dye-sensitized photoelectrochemical cell on plasmonic Ag/AgCl @ chiral TiO 2 nanofibers for treatment of urban wastewater effluents, with simultaneous production of hydrogen and electricity

“…nutrients) in contaminated water and wastewater, making 11 this the main scientific and technological challenge for the water industry. In this study, 12 inspired by the PhotoFuelCell system proposed by Lianos and coworkers [16][17][18][19], we 13 demonstrate that dye-sensitized photoelectrochemical cells (DSPCs) may be valuable 14 to address this technological issue. 15 The concept of DSPCs was similar with that of dye-sensitized solar cells (DSSCs).…”

“…H 2 O 2 , HO·, O 2 · -) which can attack and oxidize organic contaminants, ultimately 18 leading to complete mineralization. 19 The utilization of freely available solar energy as the only energy input makes 20 photocatalysis a sustainable and green process.…”

“…The amount 16 of hydrogen, the concentrations of EE2, TOC, TN and DO were measured as shown 17 our previous studies [4,14,25]. Briefly, the concentration of EE2 was detected by 18 High Performance Liquid Chromatography (HPLC, Agilent 1100). TOC was 19 measured by means of a Shimadzu TOC-V VPN with an ANSI-V auto sampler.…”