Arsine Evolution and Water Reduction at an Arsenic Cathode

Abstract

The effects of current density, temperature, acidity, and salt concentration on the evolution of arsine have been studied at arsenic and lead‐arsenic cathodes. Analysis of the data indicates that the surface of the electrode is largely covered with chemisorbed hydrogen at current densities as low as 5–10 ma/cm2, that arsine is formed by reduction of water molecules on the chemisorbed layer of hydrogen, that the rate‐determining step is the disproportionation between adjacent surface hydrides, and that water molecule reduction takes place at the electrode even in 1M sulfuric acid at current densities at least as low as 1 ma/cm2.

Application of alkaline mode electrochemical hydride generation for the detection of As and Sb using atomic fluorescence spectrometry

“…The RCS of AsH 3 formation in both acidic and neutral solutions is reaction (2) and has been well explained by Salzberg and Goldschmidt [24]. We believe that this interpretation is also suitable for alkaline media.…”

“…Mechanisms have also been proposed for the generation of volatile hydrides based on cathodic hydrogen formation (electrocatalytic or electrochemical, depending on the hydrogen overvoltage of the cathode material) [10].The proposed hydride-forming mechanism involves four steps [9,10,24,28]:…”

“…Salzberg and Goldschmidt [24] proposed that the ratecontrolling step (RCS) was disproportional between As-H and adjacent As-H 2 groups (or molecules) both in neutral and acidic solutions. The reduction of water molecules instead of hydronium ions plays an important role in the process of AsH 3 formation.…”

Flow Injection Electrochemical Hydride Generation of Hydrogen Selenide on Lead Cathode: Critical Study of the Influence of Experimental Parameters

“…It consisted of (1) the deposition of the analyte in elemental form on the electrode surface and (2) the formation of the hydride from the deposited analyte. This second process has been described by Salzberg 29 for arsine generation from arsenic and arsenic-lead electrodes. He proposed that arsine was formed by reduction of water molecules on arsenic atoms, which became covered with chemisorbed hydrogen in the form of monohydrogen and dihydrogen arsenic species.…”

Electrochemical hydride generation of tin(II) and its determination by electrothermal atomic absorption spectrometry within situtrapping in the graphite tube atomizer

“…The electrolytic formation of volatile hydride has been studied in detail by inorganic chemists and electrochemists (Salzberg and Goldschmidt 1960;Tomlinson 1964). To summarize, electrochemical generation of volatile hydrides can be considered to involve four steps as suggested (Laborda, Bolea, and Castillo 2007):…”