Cadmium sulphide nanoparticles (6-12 nm) are prepared by a precipitation process using different zeolite matrices as templates. The nanoparticles were characterized by UV-Vis, XRD, SEM, TEM and sorptometric techniques. XRD study shows the presence of hexagonal and cubic phases for the nanoparticles whereas in case of the bulk samples only the hexagonal phase is observed. These nanomaterials have been used as catalysts for the photocatalytic decomposition of water. The nanoparticles show a higher hydrogen evolution rate compared to the bulk samples which correlates well with the particle size and surface area. Noble metal (Pt, Pd, Rh, Ru)-loaded samples were subsequently prepared and tested for hydrogen evolution reaction. The presence of Pt metal is found to enhance the hydrogen production rate whereas the hydrogen production rate is retarded in the presence of Ru metal. This has been explained on the basis of metal hydrogen bond, redox potential and work function of the noble metal. © 2005 International Association for Hydrogen Energy.

Balasubramanian Viswanathan

Ram Prasad Viswanath

Cadmium sulfide

decomposition

Hydrogen bonds

Photocatalysis

Precipitation (chemical)

Scanning electron microscopy

Transmission electron microscopy

X ray diffraction

zeolites

CdS nanoparticles

Hydrogen production

Water splitting

ZEOLITE TEMPLATES

Nanostructured materials

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

International Journal of Hydrogen Energy

The possibility of hydrogen production by photo-catalytic decomposition of water on titania has provided the incentive for intense research. Titania is the preferred semiconductor for this process, in spite of its large band gap (3.2eV) that restricts its utility only in the UV region. Various sensitization methodologies have been adopted to make titania to be active in the visible region. Doping of TiO2 with nitrogen is one such method. The purpose of this presentation is to examine the state and location of nitrogen introduced in TiO2 lattice and how far the shift of optical response to visible radiation can be beneficial for the observed photo-catalysis. The specific aspects that are discussed in this article are: (i) N-doped titania surface adopts a non-native configuration, though the bulk material is still in the native configuration of pure TiO2 (ii) Though the nitrogen doped materials showed optical response in the visible region, the changes/improvements in photo-catalytic activity are only marginal in most of the cases. (iii) The exact chemical nature/state of the introduced nitrogen, and its location in titania lattice, substitutional and/or interstitial, is still unclear (iv) Is there a limit to the incorporation of nitrogen in the lattice of TiO2? Copyright © 2012 B. Viswanathan and K. R. Krishanmurthy.

Fulltext

International Journal of Photoenergy

Nitrogen incorporation in TiO 2: Does it make a visible light photo-active material?

A novel composite photocatalyst of indium doped cadmium sulfide dispersed on zirconium oxide has been synthesized, which shows enhanced photocatalytic activity for hydrogen generation from water. In this system, cadmium sulfide exists as a separate dispersed phase on the zirconia support. Optical absorption spectra indicate a blue shift of absorption edge for CdS and In doped CdS dispersed on ZrO2 compared to pure CdS and indium doped CdS. Among the supported CdS, In doped CdS exhibits better optical absorption property. Photocatalytic studies for hydrogen generation from water show an enhanced activity for CdS dispersed on ZrO2 and indium doping in CdS enhances the activity further. Fluorescence lifetime studies indicate that, in the supported CdS, the charge carriers have higher lifetime than that in the unsupported CdS. Photocurrent response experiments show a relatively higher current output for the In doped CdS dispersed on ZrO2 support. The enhanced photocatalytic activity of this composite sample is attributed to a combination of factors like enhanced lifetime of the photogenerated charge carriers, increased photoresponse and improved surface area. The present study leads to a new observation that the photocurrent response and photocatalytic activity of CdS and indium doped CdS are enhanced when they are dispersed on a support like ZrO2. These composites with Pd as co-catalyst exhibit a large increase in the photocatalytic activity due to the increased availability of electrons on the metal surface by the interfacial transfer of electrons from CdS to Pd, when irradiated. © 2011 The Royal Society of Chemistry.

Journal of Materials Chemistry

Improved photocatalytic activity of indium doped cadmium sulfide dispersed on zirconia

Cubic mesoporous CdS crystalline nanoparticles (4-6 nm) have been prepared by template-free ultrasonic-mediated precipitation, employing simple inorganic precursors at room temperature. The N2 adsorption-desorption isotherm reveals that the as-prepared CdS nanoparticle has an average pore size of ≈5.4 nm. Copyright © 2007 The Chemical Society of Japan.

Chemistry Letters

Ultrasonic-mediated preparation of mesoporous crystalline CdS nanoparticle

Mesoporous CdS nanoparticles with an average pore size of 54 Å and a particle size of 4-6 nm have been prepared by template free ultrasonic mediated precipitation at room temperature. The as prepared particles have been characterized by UV-vis spectroscopy, XRD, N2 adsorption-desorption isotherms, SEM and TEM techniques. The photocatalytic hydrogen production activity for the pure, noble metal loaded and supported mesoporous CdS has been studied. The photocatalytic activity has been compared with bulk and nanosize CdS prepared in our earlier studies. Among the prepared catalysts, Pt metal loaded mesoporous CdS shows highest hydrogen production rate of 1415 μmol/h/0.1 g catalyst. In the case of supported systems, irrespective of the particle size the basic MgO support shows higher activity than alumina support. © 2007 Elsevier B.V. All rights reserved.

Catalysis Today

Photocatalytic generation of hydrogen over mesoporous CdS nanoparticle: Effect of particle size, noble metal and support

The novel zirconium oxide, nickel oxide and zinc oxide nanoparticles supported activated carbons (Zr-AC, Ni-AC, Zn-AC) were successfully fabricated through microwave irradiation method. The synthesized nanoparticles were characterized using XRD, HR-SEM, XPS and BET. The optical properties of Zr-AC, Ni-AC and Zn-AC composites were investigated using UV-Vis diffuse reflectance spectroscopy. The photocatalytic efficiency was verified in the degradation of textile dyeing wastewater (TDW) in UV light irradiation. The chemical oxygen demand (COD) of TDW was observed at regular intervals to calculate the removal rate of COD. Zn-AC composites showed impressive photocatalytic enrichment, which can be ascribed to the enhanced absorbance in the UV light region, the effective adsorptive capacity to dye molecules, the assisted charge transfer and the inhibited recombination of electron-hole pairs. The maximum TDW degradation (82% COD removal) was achieved with Zn-AC. A possible synergy mechanism on the surface of Zn-AC was also designed. Zn-AC could be reused five times without exceptional loss of its activity. © 2015 The Nonferrous Metals Society of China.

Transactions of Nonferrous Metals Society of China

Photocatalytic degradation of textile dyeing wastewater through microwave synthesized Zr-AC, Ni-AC and Zn-AC

The photocatalytic reduction of dinitrogen to ammonia is influenced by the nature and amount of metal loading on TiO2. The optimum metal content varies depending on the nature of the metal. A correlation between the ammonia yield and the intermediary M-H bond strength is established (low bond strength gives rise to low ammonia yield).

Journal of Photochemistry and Photobiology A: Chemistry

Photocatalytic reduction of dinitrogen to ammonia over noble-metal-loaded TiO2

Photocatalytic water decomposition for hydrogen production over silicotungstic acid–silica photocatalyst

The Journal of Physical Chemistry B

Size and Structure-Dependent Photocatalytic Activity of Jingle-Bell-Shaped Silica-Coated Cadmium Sulfide Nanoparticles for Methanol Dehydrogenation

Photo-production of hydrogen over the CdS–TiO2 nano-composite particulate films treated with TiCl4

Chemical Physics Letters

Photocatalytic H2 evolution under visible light irradiation on CdS/ETS-4 composite

Alternate synthetic strategy for the preparation of CdS nanoparticles and its exploitation for water splitting

Journal	International Journal of Hydrogen Energy
ISSN	03603199
Open Access	No