Photocatalytic hydrogen production of the CdS/TiO2-WO3 ternary hybrid under visible light irradiation (original) (raw)
Related papers
ACS applied energy materials, 2018
Photocatalytic water splitting under visible light has attracted attention as a possible solution to the energy exhaustion problem. Hitherto, water splitting has been generally achieved using several oxynitrides, oxysulfides, and nitrides, and only a few studies report water splitting using cadmium sulfide (CdS) as a photocatalyst. A major reason for this is that CdS undergoes photocorrosion. In this study, we achieved an overall water splitting under visible light using a CdS/ WO 3 /CdWO 4 tricomposite photocatalyst. In the process, photocorrosion of CdS was suppressed by covering it with WO 3 and CdWO 4 , and the oxidation reaction progressed in WO 3 by the Z-scheme type photocatalytic reaction.
International Journal of Hydrogen Energy, 2008
A CdS/TiO 2 composite photocatalyst consisting of one-dimensional CdS nanowire (NW) with a high crystallinity decorated with nanosized TiO 2 particles (NP) was fabricated by solvothermal method and sol-gel synthesis. The new configuration photocatalyst exhibited higher rate of hydrogen production than that of single CdS NW under visible light irradiation (l ! 420 nm) from water containing sulfide and sulfite ions as hole scavengers. Physicochemical properties of CdS NW/TiO 2 NP composite photocatalysts were investigated together with the effect of the mole ratio of TiO 2 and CdS for photocatalytic hydrogen production from water under visible light irradiation.
Journal of Photochemistry and Photobiology A: Chemistry, 2007
A CdS/TiO 2 nano-bulk composite photocatalyst consisting of bulky CdS with a high crystallinity decorated with nanosized TiO 2 particles was fabricated by precipitation method and sol-gel synthesis. This configuration of the composite photocatalyst exhibited a very high rate of hydrogen production under visible light irradiation (λ ≥ 420 nm) from water containing sulfide and sulfite as hole scavengers. In this work, we investigated the physicochemical properties of CdS(bulk)/TiO 2 composite photocatalysts and optimized their preparation conditions for the high photocatalytic activity of hydrogen production from water containing Na 2 S and Na 2 SO 3 as a sacrificial reagents under visible light irradiation.
Nanotechnology, 2016
Hydrogen fuels generated by water splitting using a photocatalyst and solar irradiation are currently gaining the strength to diversify the world energy matrix in a green way. CdS quantum dots have revealed a hydrogen generation improvement when added to TiO2 materials under visible-light irradiation. In the present paper, we investigated the performance of TiO2 nanotubes coupled with CdS quantum dots, by a molecular bifunctional linker, on photocatalytic hydrogen generation. TiO2 nanotubes were obtained by anodization of Ti foil, followed by annealing to crystallize the nanotubes into the anatase phase. Afterwards, the samples were sensitized with CdS quantum dots via an in situ hydrothermal route using 3-mercaptopropionic acid as the capping agent. This sensitization technique permits high loading and uniform distribution of CdS quantum dots onto TiO2 nanotubes. The XPS depth profile showed that CdS concentration remains almost unchanged (homogeneous), while the concentration rela...
Review of photocatalytic water-splitting methods for sustainable hydrogen production
This paper examines photocatalytic hydrogen production as a clean energy solution to address challenges of climate change and environmental sustainability. Advantages and disadvantages of various hydrogen production methods, with a particular emphasis on photocatalytic hydrogen production, are discussed in this paper. Social, environmental and economic aspects are taken into account while assessing selected production methods and types of photocatalysts. In the first part of this paper, various hydrogen production options are introduced and comparatively assessed. Then, solar-based hydrogen production options are examined in a more detailed manner along with a comparative performance assessment. Next, photocatalytic hydrogen production options are introduced, photocatalysis mechanisms and principles are discussed and the main groups of photocatalysts, namely titanium oxide, cadmium sulfide, zinc oxide/sulfide and other metal oxide-based photocatalyst groups, are introduced. After discussing recycling issues of photocatalysts, a comparative performance assessment is conducted based on hydrogen production processes (both per mass and surface area of photocatalysts), band gaps and quantum yields. The results show that among individual photocatalysts, on average, Au–CdS has the best performance when band gap, quantum yield and hydrogen production rates are considered. From this perspective, TiO 2 –ZnO has the poorest performance. Among the photocatalyst groups, cadmium sulfides have the best average performance, while other metal oxides show the poorest rankings, on average.
The Journal of Physical Chemistry C, 2008
CdS/TiO 2 composite photocatalysts were platinized by different methods such as photodeposition (PD), wet impregnation (WI), and chemical reduction (CR), and studied for hydrogen production from water under visible light. All Pt species were in the metallic state, yet PD and WI photocatalysts contained electrondeficient Pt. In particular, Pt-Ti formation was identified in the WI catalyst, which contributed to electron deficiency of Pt. These two photocatalysts of electron-deficient Pt exhibited higher rates of hydrogen evolution due to favorable diffusion of photoelectrons from excited CdS toward the Pt. Between PD and WI photocatalysts, the PD catalyst showed a lower rate because part of the Pt in the catalyst resided on CdS, whereas all Pt species were located on TiO 2 nanoparticles for WI and CR catalysts. The results indicate that the location as well as the electronic state of Pt is important for the high performance of platinized CdS/TiO 2 photocatalysts in hydrogen production from water.
Journal of Nanoparticle Research, 2018
Fabrication of advanced semiconductor system for photocatalytic water splitting into valuable hydrogen energy has attracted a lot of attention worldwide due to the increasing global energy crises. In this work, a ternary WO 3-Pt-CdS composite was synthesized through coprecipitation and hydrothermal reactions. The ternary composite (i.e. WO 3-Pt-CdS) showed a high hydrogen evolution rate of 3 9 0 μ m o l h − 1 g − 1 e x c e e d i n g C d S a l o n e (27 μmol h −1 g −1), WO 3-CdS (55 μmol h −1 g −1), and CdS-Pt (135 μmol h −1 g −1). The enhanced photocatalytic activity is mainly attributed to the formation of Z-scheme heterojunction between WO 3 and CdS, which results in the effective space charge separation. Meanwhile, the Pt in the as-prepared WO 3-Pt-CdS plays an essential role as a bridge for accelerating the charge transportation between WO 3 and CdS. This work provides another effective way of developing visible-light-driven photocatalysts for practical application.
Journal of Nanoparticle Research, 2013
In this work, we developed a new type of nanostructured photoanodes for photoelectrochemical water splitting. They are based on CdS-TiO 2 nanocomposite films, supported on conductive Ti sheets, prepared by an easy-to-achieve three-step method. It involves the production of TiO 2 nanofibers (NFs) using a controlled corrosion route of polished Ti sheets, the preparation of size-controlled CdS quantum dots (QDs) by the polyol process and the direct impregnation of TiO 2 /Ti sheets by QDs in suspension. The photoelectrochemical (PEC) properties of the resulting nanostructures were measured, using a homemade electrochemical cell illuminated with a standard Xenon lamp, and compared to those of bare TiO 2 NFs. A net enhancement of the photocurrent was observed after CdS impregnation, suggesting a low carrier recombination rate and a higher efficiency of the PEC device for solar water splitting, as the induced photocurrent is related to the electrons needed to reduce H + ions into H 2 at the cathode electrode (Pt wire). Keywords TiO 2 nanofibers CdS quantum dots CdS-TiO 2 /Ti nanocomposites Photoelectrochemical properties X-ray photoelectron spectroscopy Electron microscopy Energy conversion