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Journal ArticleDOI

Rhodium and rhodium sulfide coated cadmium sulfide as a photocatalyst for photochemical decomposition of aqueous sulfide

01 Mar 1990-Langmuir (American Chemical Society)-Vol. 6, Iss: 3, pp 565-567
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.
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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 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

Journal ArticleDOI
TL;DR: In this paper, a visible light sensitive and highly active Cu-doped ZnS hollow photocatalyst particles "Cu-ZnS-shell" were successfully developed.
Abstract: Visible light sensitive and highly active Cu-doped ZnS hollow photocatalyst particles “Cu-ZnS-shell” were successfully developed. These particles could generate H2 through photocatalytic decomposition of HS− ion in Na2S solution. The photoactivity under xenon lamp irradiation was 6 and 130 times higher than that of copper-free “ZnS-shell” and coprecipitated ZnS particles, respectively. “Cu-ZnS-shell” particles were prepared by doping the “ZnS-shell” particles synthesized using zinc oxide as precursor with Cu, utilizing the difference in ionization tendency between zinc and copper. Though the photoactivity of “ZnS-shell” was higher than that of coprecipitated ZnS, their photoactivity under visible light conditions was low. However, the “Cu-ZnS-shell” was active to light of wavelengths higher than 440 nm and is preferred over CdS, which requires an expensive support metal catalyst such as platinum to decompose HS− ion.

161 citations

Journal ArticleDOI
TL;DR: In this article, the basic mechanistic fundamentals of CdX photocatalysts and various strategies to enhance the activity and stability of this class of photocatalyst are introduced in detail.
Abstract: Semiconductor-based photocatalytic hydrogen (H2) production from water has recently received considerable attention because of its enormous potential for solving worldwide ever-increasing energy crises and environmental issues. Among various semiconductors, cadmium chalcogenides (CdX, X = S, Se, Te), with a variety of superior properties including appropriate bandgaps for visible-light absorption, proper conduction band edge potentials for water reduction and abundant reserves on the earth, have fuelled great interest in exploring their photocatalytic properties for solar-driven H2 production from water. This review article summarizes the recent progress in developing CdX-based photocatalyst systems for the production of H2 from solar water splitting. The basic mechanistic fundamentals of CdX photocatalysts and various strategies to enhance the activity and stability of this class of photocatalysts are introduced in detail. Finally, some key scientific issues and prospective directions in this area of research are also discussed.

138 citations