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I. B. Rufus

Bio: I. B. Rufus is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: X-ray photoelectron spectroscopy & Cadmium sulfide. The author has an hindex of 5, co-authored 7 publications receiving 82 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the in situ deposition of Pt and Ir on CdS during the photocatalytic decomposition of aqueous sulfide results in the formation of an effective bifunctional photocatalyst (MS/CdS/M), where MS is Pt or Ir sulfide and M is P or Ir.
Abstract: The in situ deposition of Pt and Ir on CdS during the photocatalytic decomposition of aqueous sulfide results in the formation of an effective bifunctional photocatalyst (MS/CdS/M, where MS is Pt or Ir sulfide and M is Pt or Ir) which is more active than CdS and metallized CdS. In situ metallization provides a convenient method for the preparation of metal- and metal-sulfide-deposited CdS. The order of reactivity for the in situ metallization of CdS in the case of the photocatalytic decomposition of aqueous sulfide is Rh > Pt > Ru = Ir > Co ≃ Ni ≃ Fe. Based on the observed results a mechanism for the photocatalytic decomposition of aqueous sulfide is proposed.

31 citations

Journal ArticleDOI
01 Mar 1990-Langmuir
TL;DR: In this article, the ternary material, viz., Rh{sub 2}S{sub 3}/Rh/CdS, is found to be the most active photocatalyst for the decomposition of aqueous sulfide.
Abstract: Among CdS, Rh/CdS, Rh{sub 2}S{sub 3}/CdS, and Rh{sub 2}S{sub 3}/Rh/CdS, the ternary material, viz., Rh{sub 2}S{sub 3}/Rh/CdS, is found to be the most active photocatalyst for the decomposition of aqueous sulfide. X-ray photoelectron spectroscopic studies show that Rh as it is photodeposited on CdS is in the zero oxidation state but is prone to aerial oxidation.

24 citations

Journal ArticleDOI
TL;DR: Ramakrishnan et al. as discussed by the authors used X-ray photoelectron spectroscopy (XPS) to probe the surface of materials and obtained a detailed surface study of Pd/CdS.
Abstract: I. B. RUFUS*,V. RAMAKRISHNAN, B. VISWANATHAN, J. C. KURIACOSE Department of Chemistry, Indian Institute of Technology, Madras 600036, India Metallized CdS is used as a photocatalyst for many reactions and as a photoanode in photoelectrochem- ical (PEC) cells [1-4]. Conversion and storage of solar energy can be achieved by means of photocata- lysis as well as by PEC cells. The photocatalytic and photoelectrochemical properties of metallized CdS depend on its surface properties. Pd/CdS is a better photocatalyst and photoanode than CdS [3]. However, a detailed surface study of Pd/CdS is lacking. X-ray photoelectron spectroscopy (XPS) is a versatile tool to probe the surface of materials. XPS investigation of Pd/CdS will yield useful infor- mation such as the oxidation state of Pd, the contact between Pd and CdS, and other species present on the surface. Metallized CdS is mostly prepared by the photodeposition of noble metals [1, 3, 4]. There- fore, in the present investigation Pd, one of the representatives of noble metals, was photodeposited on CdS and the Pd/CdS obtained was analysed by XPS. Pd, Pt, Rh, Ru and Ni/CdS were prepared by the simultaneous photodeposition (illuminating for 15 min with a 1000 W tungsten-halogen lamp) of these metals on a sintered (4 h at 873 K in nitrogen) CdS (Fluka, 99.999% purity) pellet from an equi- molar (1 x 10 -4 M) solution (acetic acid, pH 4.5) of the corresponding metal chlorides. Following a similar procedure, Pd was photodeposited from a solution of PdC12 (Arora Mathey Ltd, India). After photodeposition the pellets were washed with triply distilled water and dried in air at room temperature (303 K). The sides of the pellets that were exposed to visible light during the photodeposition were subjected to XPS analysis. The XPS studies were made with an ESCA Lab Mk II (VG Scientific Co., UK) at room temperature and at a pressure of 1 x 10 -7 Pa before and after sputtering with argon ions. The X-ray source used was MgKo~ with an energy of 1253.6 eV. The C ls peak at 285.0 eV was used as the internal standard. In the cases of Pd, Pt, Rh, Ru and Ni/CdS prepared by the simultaneous photodeposition of these metals, the Pd 3d and 3p binding energies (Figs 1 and 2) are higher than those reported for Pd metal, viz. 344.7, 340.0 and 531.5 eV [5], indicating that Pd which is on the surface of CdS is not in the zero oxidation state. The several Pd-O species identified are shown in Table I. Hence, in the case of Pd/CdS the XPS spectra were recorded only after argon-ion sputtering, in order to study the surface free of oxide

8 citations

01 Jan 1993
TL;DR: Ramakrishnan et al. as discussed by the authors used X-ray photoelectron spectroscopy (XPS) to probe the surface of materials and obtained a detailed surface study of Pd/CdS.
Abstract: I. B. RUFUS*,V. RAMAKRISHNAN, B. VISWANATHAN, J. C. KURIACOSE Department of Chemistry, Indian Institute of Technology, Madras 600036, India Metallized CdS is used as a photocatalyst for many reactions and as a photoanode in photoelectrochem- ical (PEC) cells [1-4]. Conversion and storage of solar energy can be achieved by means of photocata- lysis as well as by PEC cells. The photocatalytic and photoelectrochemical properties of metallized CdS depend on its surface properties. Pd/CdS is a better photocatalyst and photoanode than CdS [3]. However, a detailed surface study of Pd/CdS is lacking. X-ray photoelectron spectroscopy (XPS) is a versatile tool to probe the surface of materials. XPS investigation of Pd/CdS will yield useful infor- mation such as the oxidation state of Pd, the contact between Pd and CdS, and other species present on the surface. Metallized CdS is mostly prepared by the photodeposition of noble metals [1, 3, 4]. There- fore, in the present investigation Pd, one of the representatives of noble metals, was photodeposited on CdS and the Pd/CdS obtained was analysed by XPS. Pd, Pt, Rh, Ru and Ni/CdS were prepared by the simultaneous photodeposition (illuminating for 15 min with a 1000 W tungsten-halogen lamp) of these metals on a sintered (4 h at 873 K in nitrogen) CdS (Fluka, 99.999% purity) pellet from an equi- molar (1 x 10 -4 M) solution (acetic acid, pH 4.5) of the corresponding metal chlorides. Following a similar procedure, Pd was photodeposited from a solution of PdC12 (Arora Mathey Ltd, India). After photodeposition the pellets were washed with triply distilled water and dried in air at room temperature (303 K). The sides of the pellets that were exposed to visible light during the photodeposition were subjected to XPS analysis. The XPS studies were made with an ESCA Lab Mk II (VG Scientific Co., UK) at room temperature and at a pressure of 1 x 10 -7 Pa before and after sputtering with argon ions. The X-ray source used was MgKo~ with an energy of 1253.6 eV. The C ls peak at 285.0 eV was used as the internal standard. In the cases of Pd, Pt, Rh, Ru and Ni/CdS prepared by the simultaneous photodeposition of these metals, the Pd 3d and 3p binding energies (Figs 1 and 2) are higher than those reported for Pd metal, viz. 344.7, 340.0 and 531.5 eV [5], indicating that Pd which is on the surface of CdS is not in the zero oxidation state. The several Pd-O species identified are shown in Table I. Hence, in the case of Pd/CdS the XPS spectra were recorded only after argon-ion sputtering, in order to study the surface free of oxide

7 citations


Cited by
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Journal ArticleDOI
TL;DR: A review of the known inorganic catalysts with a focus on structure-activity relationships is given in this article, where the first water splitting system based on TiO2 and Pt was proposed by Fujishima and Honda in 1972.
Abstract: Photochemical splitting of water into H2 and O2 using solar energy is a process of great economic and environmental interest. Since the discovery of the first water splitting system based on TiO2 and Pt in 1972 by Fujishima and Honda, over 130 inorganic materials have been discovered as catalysts for this reaction. This review discusses the known inorganic catalysts with a focus on structure–activity relationships.

1,977 citations

Journal ArticleDOI
TL;DR: For a variety of metals and semiconductors, an attempt is made to generalize observations in the literature on the effect of process conditions applied during photodeposition on (i) particle size distributions, (ii) oxidation states of the metals obtained, and (iii) consequences for photocatalytic activities.
Abstract: In this review, for a variety of metals and semiconductors, an attempt is made to generalize observations in the literature on the effect of process conditions applied during photodeposition on (i) particle size distributions, (ii) oxidation states of the metals obtained, and (iii) consequences for photocatalytic activities. Process parameters include presence or absence of (organic) sacrificial agents, applied pH, presence or absence of an air/inert atmosphere, metal precursor type and concentration, and temperature. Most intensively reviewed are studies concerning (i) TiO2; (ii) ZnO, focusing on Ag deposition; (iii) WO3, with a strong emphasis on the photodeposition of Pt; and (iv) CdS, again with a focus on deposition of Pt. Furthermore, a detailed overview is given of achievements in structure-directed photodeposition, which could ultimately be employed to obtain highly effective photocatalytic materials. Finally, we provide suggestions for improvements in description of the photodeposition methods applied when included in scientific papers.

648 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present recent research progress in the development of visible light driven sulphide photocatalysts, focusing on the expansion of solar spectrum response and enhancement of charge separation efficiency.

451 citations

Journal ArticleDOI
TL;DR: In this article, a chemically stable cubic spinel nanostructured CdIn2S4 prepared by a facile hydrothermal method is reported as a visible-light driven photocatalyst.
Abstract: Nanostructured photocatalysts with high activity are sought for solar production of hydrogen. Spinel semiconductors with different nanostructures and morphologies have immense importance for photocatalytic and other potential applications. Here, a chemically stable cubic spinel nanostructured CdIn2S4 prepared by a facile hydrothermal method is reported as a visible-light driven photocatalyst. A pretty, marigold-like morphology is observed in aqueous-mediated CdIn2S4, whereas nanotubes of good crystallinity, 25 nm in diameter, are obtained in methanol-mediated CdIn2S4. The aqueous- and methanol-mediated CdIn2S4 products show excellent photocatalytic activity compared to other organic mediated samples, and this is attributed to their high degree of crystallinity. The CdIn2S4 photocatalyst gives quantum yields of 16.8 % (marigold-like morphology) and 17.1 % (nanotubes) at 500 nm, respectively, for the H2 evolution reaction. The details of the characteristics of the photocatalyst, such as crystal and band structure, are reported. Considering the importance of hydrogen energy, CdIn2S4 will be an excellent candidate as a catalyst for “photohydrogen” production under visible light. Being a nanostructured chalcogenide semiconductor, CdIn2S4 will have other potential prospective applications, such as in solar cells, light-emitting diodes, and optoelectronic devices.

330 citations

Journal ArticleDOI
TL;DR: In this paper, the authors reported the synthesis of novel and highly efficient noble metal-free ultra-thin MoS 2 (UM) layers on exfoliated reduced graphene oxide (ERGO) nanosheets as a cocatalyst for CdS nanorods.
Abstract: The development of novel highly efficient noble metal-free co-catalysts for enhanced photocatalytic hydrogen production is of great importance. Herein, we report the synthesis of novel and highly efficient noble metal-free ultra-thin MoS 2 (UM) layers on exfoliated reduced graphene oxide (ERGO) nanosheets as a cocatalyst for CdS nanorods (ERGO/UM/CdS). A simple method different from the usual preparation techniques is used to convert MoS 2 to UM layers, graphene oxide (GO) to ERGO nanosheets, based on ultrasonication in the absence of any external reducing agents. The structure, optical properties, chemical states, and dispersion of MoS 2 and CdS on ERGO are determined using diverse analytical techniques. The photocatalytic activity of as-synthesized ERGO/UM/CdS composites is assessed by the splitting of water to generate H 2 under simulated solar light irradiation in the presence of lactic acid as a hole ( h + ) scavenger. The observed extraordinary hydrogen production rate of ∼234 mmol h −1 g −1 is due to the synergetic effect of the ultrathin MoS 2 layers and ERGO, which leads to the effective separation of photogenerated charge carriers and improves the surface shuttling properties for efficient H 2 production. Furthermore, the observed H 2 evolution rate is much higher than that for individual noble metal (Pt), ERGO and MoS 2 -assisted CdS photocatalysts. Moreover, to the best of our knowledge, this is the highest H 2 production rate achieved by a RGO and MoS 2 based CdS photocatalyst for water splitting under solar light irradiation. Considering its low cost and high efficiency, this system has great potential for the development of highly efficient photocatalysts used in various fields

163 citations