Kuppuswamy Kalyanasundaram

Bio: Kuppuswamy Kalyanasundaram is an academic researcher from École Polytechnique. The author has contributed to research in topics: Redox & Visible spectrum. The author has an hindex of 12, co-authored 19 publications receiving 906 citations. Previous affiliations of Kuppuswamy Kalyanasundaram include Engelhard.

Visible Light Induced Water Cleavage in CdS Dispersions Loaded with Pt and RuO2, Hole Scavenging by RuO2

Abstract: Illumination of aqueous CdS dispersions loaded with Pt and RuO2 by visible light produces hydrogen and oxygen in stoichiometric proportion. No degradation of the photocatalyst is noted after 60 h of irradiation time. The RuO2 deposit on the particle surface greatly accelerates the transfer of holes from the semiconductor valence band to the aqueous solution thus inhibiting photocorrosion.

Light Induced Redox Reactions of Water Soluble Porphyrins, sensitization of hydrogen generation from water by zincporphyrin derivatives

Abstract: The photoredox behaviour of two water soluble derivatives of zincporphyrin, 5,10,15,20-tetra-p-sulfonatophenyl (1) and 5,10,15,20-tetra-p-N-methylpyridiniochloride (2), was investigated using laser and continuous photolysis techniques. Photoexcitation produces triplet states whose lifetimes in aqueous solution exceeds 1 ms. These triplet states can be quenched reductively by donors such as EDTA and oxidatively by acceptors such as methylviologen (MV2+). Electron transfer to MV2+ is greatly influenced by the charge of the porphyrin, rate constants being 1.4 x 1010M−1S−1 and 2 × 106M−1S−1 for 1 and 2, respectively. In the presence of colloidal Pt catalyst, the cationic porphyrin sensitizes photoreduction of water to hydrogen with remarkable efficiency.

Visible Light Induced Generation of Hydrogen from H2S in CdS‐Dispersions, Hole Transfer Catalysis by RuO2

Abstract: Illumination of US-dispersions by visible light in solutions containing H2S or sulfide ions leads to efficient generation of hydrogen and sulfur. Very small quantities of RuO2 deposited on the CdS-particles improve markedly the quantum yield of H2-formation for which the optimum value obtained so far is ϕ = 0.35 ± 0.1. The effect of RuO2 is attributed to catalysis of hole transfer from the valence band of CdS to H2S or sulfide in solution.

Photoelectrochemical system and a method of using the same

Abstract: A photoelectrochemical system for conducting endoergic chemical processes driven by light energy. This system consists essentially of an illuminated halfcell and a darkened halfcell joined via electrodes and an external circuit to allow for the transport of electrons. Also, the said halfcells are joined by an ion conducting junction so as to allow for the transport of ions. The illuminated halfcell contains a photosensitizer, an electron relay substance and a catalyst, and the darkened halfcell may contain a second electron relay and a catalyst. Illumination with visible light results in the simultaneous and separate generation of oxidation and reduction products.

A metal-free polymeric photocatalyst for hydrogen production from water under visible light

Abstract: The production of hydrogen from water using a catalyst and solar energy is an ideal future energy source, independent of fossil reserves. For an economical use of water and solar energy, catalysts that are sufficiently efficient, stable, inexpensive and capable of harvesting light are required. Here, we show that an abundant material, polymeric carbon nitride, can produce hydrogen from water under visible-light irradiation in the presence of a sacrificial donor. Contrary to other conducting polymer semiconductors, carbon nitride is chemically and thermally stable and does not rely on complicated device manufacturing. The results represent an important first step towards photosynthesis in general where artificial conjugated polymer semiconductors can be used as energy transducers.

Understanding TiO2 photocatalysis: mechanisms and materials.

Abstract: Jenny Schneider,*,† Masaya Matsuoka,‡ Masato Takeuchi,‡ Jinlong Zhang, Yu Horiuchi,‡ Masakazu Anpo,‡ and Detlef W. Bahnemann*,† †Institut fur Technische Chemie, Leibniz Universitaẗ Hannover, Callinstrasse 3, D-30167 Hannover, Germany ‡Faculty of Engineering, Osaka Prefecture University, 1 Gakuen-cho, Sakai Osaka 599-8531, Japan Key Lab for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237, China

Artificial Photosynthesis: Solar Splitting of Water to Hydrogen and Oxygen

Abstract: The maintenance of life on earth, our food, oxygen, and fossil fuels depend upon the conversion of solar energy into chemical energy by biological photosynthesis carried out by green plants and photosynthetic bacteria. In this process sunlight and available abundant raw materials (water, carbon dioxide) are converted to oxygen and the reduced organic species that serve as food and fuel. A long-standing challenge has been the development of a practical artificial photosynthetic system that can roughly mimic the biological one, not by duplicating the self-organization and reproduction of the biological system nor the aesthetic beauty of trees and plants, but rather by being able to use sunlight to drive a thermodynamically uphill reaction of an abundant materials to produce a fuel. In this Account we focus on “water splitting”, the photodriven conversion of liquid water to gaseous hydrogen and oxygen:

Sol-gel chemistry of transition metal oxides

Abstract: Etude de la preparation d'un gel colloidal par un procede sol gel Determination des proprietes electriques et electrochimiques