FTIR Characterization of Surface Interactions of Cyanide and Copper Cyanide with a Platinum Electrode in Alkaline Solution

Abstract

In this paper, the nature of the species formed in the electrochemical interactions between a polycrystalline platinum surface and cyanide and copper-cyanide species in alkaline solution (pH 13) has been investigated by combining cyclic voltammetry with in situ FTIR spectroscopy. This study was performed because electrochemical reactors for the treatment of cyanide-containing industrial wastewaters have been shown to achieve viable destruction rates when copper ions are present in the alkaline solution through the formation of copper oxide films [1-3]. It has been found that the complexation of cyanide ions by copper species hinders the adsorption of the anion at the electrode, thus avoiding the characteristic electrode poisoning by CO that occurs in the absence of soluble copper species. Conversely, soluble copper-cyanide complexes can be electrooxidized at the platinum surface through the formation of cyanate species as intermediate, and of HCOOH and NO as end products. The addition of copper species to the electrolyte also facilitates this route for cyanide oxidation to occur at higher rates without poisoning the platinum electrode.

Electrocatalytic oxidation of cyanide on copper-doped cobalt oxide electrodes

“…Such a band was found to appear in FTIR spectra upon cyanide oxidation on various metals including Cu [58,59]. By contrast, this band is absent in the Raman spectra obtained in the present work with Cu x Co 3-x O 4 at high potentials (Fig.…”

An X-ray absorption spectroscopy investigation of the coordination environment of electrogenerated Ni(ii)-pseudohalide complexes arising from the anodic polarization of Ni electrodes in DMSO solutions of NCO−, NCS−and NCSe−ions

“…15 This enables direct correlations to be made between the electrochemical response and the chemical species observed. [16][17][18][19][20][21][22][23][24][25][26][27] The pseudohalide ions are easily identi-ed from the n(CN) stretching mode, which occurs in a region of the IR spectrum that is relatively unpopulated by other vibrational frequencies. Model solutions consisting of different Ni:pseudohalide ion ratios were synthesised and their IR spectra compared to those from the spectroelectrochemical study in an attempt to identify the complexes formed.…”

A Combined SNIFTIRS and XANES Study of Electrically Polarized Copper Electrodes in DMSO and DMF Solutions of Cyanate (NCO−), Thiocyanate (NCS−) and Selenocyanate (NCSe−) Ions

“…12 In situ IR spectroelectrochemistry can provide detailed information on electrochemical processes. [13][14][15][16][17][18][19][20][21][22] It is also valuable for characterizing the molecular species generated, especially in conjunction with conventional electrochemical techniques such as cyclic voltammetry, which is unable to identify discrete molecular compounds. Thiocyanate (and other pseudohalide ions) can be detected easily using IR spectroscopy, because the signal from the -CN moiety occurs in a region of the spectrum where few other fundamental vibrations are detected (2500-1800 cm −1 ), thus allowing any speciation that occurs as a result of electrochemical processes to be followed.…”