Oxidative IR Spectroelectrochemistry of Copper in Methanol Containing Carbon Monoxide

Abstract

IR spectroelectrochemistry was used to examine the electro-oxidation behavior of carbon monoxide in methanol at a polycrystalline copper electrode. Under such neutral conditions copper electrodes are coated with ill-defined copper oxides and hydroxides and at the oxidative potentials can be expected to generate soluble copper species. The electrochemistry displayed complex behavior suggesting that methanol oxidation was one prominent reaction. However, the spectroscopy revealed that very little methanol oxidation had occurred and that carbon monoxide was not adsorbed to the copper electrode. Instead, the electro-oxidation generated an intense IR band at 2107 cm(-1) that was attributed to a soluble [Cu(I)CO](+) species.

Electrochemically Generated Copper Carbonyl for Selective Dimethyl Carbonate Synthesis

“…The reaction peaks indicate a degree of reversibility for some of the oxidation processes recorded, however, as the oxidation peak area is visibly larger than the reduction peak area, irreversible reactions are likely occurring, such as the oxidation of the solvent. The CV is comparable to that recorded in a similar electrolyte solution, where a broad oxidation peak is shown in the forward scan and a smaller reduction peak observed in the reverse scan …”

“…The latter is due to water oxidation in the thin layer, while the former band at 2106 cm –1 should be related with a CO species as it falls in the vibrational region where carbonyl bands are expected. In fact, such a band has been ascribed in literature to the formation of a Cu­(I)­CO complex in solution. ,, Furthermore, the band does not change with the applied potential, suggesting that it is indeed related with a solution species.…”

“…In fact, such a band has been ascribed in literature to the formation of a Cu(I)CO complex in solution. 29,34,35 Furthermore, the band does not change with the applied potential, suggesting that it is indeed related with a solution species.…”

“…The CV is comparable to that recorded in a similar electrolyte solution, where a broad oxidation peak is shown in the forward scan and a smaller reduction peak observed in the reverse scan. 29 On the addition of carbon monoxide (CO) gas to the electrolyte solution, a large oxidation peak Ox3 appears (Figure 1). The onset of this peak is before the onset of copper oxidation observed without CO present in the argon saturated electrolyte solution.…”

In Situ Generation of the Surface Oxygen Vacancies in a Copper–Ceria Catalyst for the Water–Gas Shift Reaction

“…Here, the band at around 2095 cm –1 was also assigned as Cu­(Ι)–CO, rather than Cu(0)–CO. Based on the previous reports, ,− CO was bonded via σ- and π-back bonds to Cu + species because of its d-electron (3d 10 ). As a result of the synergistic effects between the two bonds, the Cu­(Ι)–CO species are characterized by a high stability.…”