Browsing by Author "Tseung, Alfred C. C."

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    Catalyst participation in the reduction of sulphur dioxide by carbon monoxide in the presence of water and oxygen
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1978, 74 (08), 1978) Hibbert, D. Brynn; Tseung, Alfred C. C.
    Copper supported on alumina is a catalyst for the reduction of sulphur dioxide by carbon monoxide. In the presence of water and oxygen, calculation of the equilibrium state of the gas phase and condensed phase by a free energy minimisation method reveals that for certain combinations of gas composition and temperature, copper(II) sulphide will be formed. Copper was converted to copper sulphide when used as a catalyst for the reduction of a stoichiometric mixture of sulphur dioxide and carbon monoxide containing 2.4 % water at 580°C. Oxygen is a poison for the reaction.
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    Chemical and electrochemical kinetics of CuII reduction in chloride media
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1978, 74 (08), 1978) Hibbert, D. Brynn; Sugiarto, Herman; Tseung, Alfred C. C.
    The deposition and dissolution of copper from copper sulphate solutions have been studied by galvanostatic measurements. From current overpotential relations it is concluded that the rate limiting step in the electrochemical reduction or oxidation at pH 1 is the reaction Cu2++ e ⇌ Cu+. In the presence of chloride and sulphite ions, the CuCl–2 complex is formed which stabilises the CuI state. The rate limiting step is now the reduction of this complex. Anodically the slow step is the oxidation of CuCl–2. The addition of sulphite ions chemically reduces CuII to CuI, but the rate is much slower than the electrochemical reduction at an overpotential of –100 mV. At pH 1 chemical dissolution of the copper deposited at the cathode occurs.