Effect of Surfactants on Cathode Deposition of Tellurium from Alkaline Solutions
A.G. BELOBABA, A. I. MASLIY
Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: поверхностно-активные вещества, скорость реакций, осаждение теллура, образование дителлурид-анионов, щелочные растворы, морфология поверхности, surfactants, rate of reactions, tellurium deposition, formation of ditelluride anions, alkaline solutions, surface morphology
Abstract
The effect of surfactants on the rate of the target reaction of tellurium precipitate from alkaline tellurium solutions and the side reaction of further reduction to ditelluride anions, and also current efficiency and morphology of cathode tellurium precipitates is examined on a graphite electrode pre-coated with tellurium sludges by the voltammetry method. Sodium lignosulphonate and polyvinyl alcohol have a weak effect on the rates of both cathode reactions and therefore on morphology of tellurium precipitates, as demonstrated. Tetrabutyl ammonium hydroxide additive inhibits both reactions but simultaneously worsens the quality of cathode precipitate: there generated a powdery sludge that is partly poured out from the substrate and is almost completely rinsed away upon water washing. The most efficient additive to obtain dense tellurium precipitates is OP-10 wetting agent. It substantially inhibits tellurium deposition and suppresses the side reaction of its dissolution in the virtually important range of potentials until the maximum current. At the same time, OP-10 significantly improves precipitate morphology and ensures obtaining fine-crystalline dense cathode tellurium precipitates.
DOI: 10.15372/CSD20180102
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