A contribution to the mechanism of “reduced” CO₂ adsorbates electro-oxidation from combined spectroelectrochemical and voltammetric data

The nature of reduced CO2 adsorbates, as well as the mechanisms for their electro-oxidation on platinum, have been reviewed through the light of new experimental data obtained by cyclic voltammetry and by Fourier transform infrared reflectance spectroscopy. Three different “reduced” CO2 adsorbates are described as “‘ensembles”. It is suggested that they involve different extents of adsorbed entities, among which weakly bound and strongly bound hydrogen atoms play the most important role.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Chemisorption of methanol on different platinum electrodes (smooth and rough polycrystalline, monocrystalline, and preferentially oriented), as studied by EMIRS

EMIR spectra of methanol electroadsorbates on smooth and rough polycrystalline, monocrystalline and preferentially oriented platinum electrodes are reported. The (100)-type preferred oriented platinum behaves approximately as Pt (100) single crystals. On electrodispersed platinum electrodes the poisoning phenomena due to CO adsorbates appear to be reduced as compared to smooth platinum electrodes. EMIRS results correlate well with the electrochemical behaviour of the different platinum electrodes for methanol electrooxidation.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Ethanol separation using Sepabeads207 adsorbent

This work was aimed at evaluating the ethanol separation using Sepabeads207 adsorbent. A 10 wt% of ethanol solution was used as a model fermentation broth. The separation of ethanol from the solution was performed in a tube containing Sepabeads207 at different operating conditions: temperatures, 20 to 40°C; solution pH, 4 to 7; and contact times, 5 to 25 minutes. Recovery of ethanol via stripping was studied between 15 and 35 minutes, and at different air temperatures of 80 to 95°C. The concentration of liquid ethanol was measured using gas chromatography and refractometer. A higher ethanol concentration by Sepabeads207 adsorption was obtained at 20°C and solution pH 4 for 5 minutes, while the recovery was performed better at 80°C for 15 minutes. By applying these conditions, 10 wt% of ethanol in the solution was concentrated to 46 wt%. The ethanol adsorption data are: i). capacity of 0.22 g ethanol/g adsorbent, ii). selectivity of 7.75 (g ethanol/g water (adsorbed)) / (g ethanol/g water (original solution)), and iii). efficiency of 100%. Sepabeads207 is a promising adsorbent for ethanol separation from the dilute ethanol solution

A contribution to the mechanism of “reduced” CO₂ adsorbates electro-oxidation from combined spectroelectrochemical and voltammetric data

The nature of reduced CO2 adsorbates, as well as the mechanisms for their electro-oxidation on platinum, have been reviewed through the light of new experimental data obtained by cyclic voltammetry and by Fourier transform infrared reflectance spectroscopy. Three different “reduced” CO2 adsorbates are described as “‘ensembles”. It is suggested that they involve different extents of adsorbed entities, among which weakly bound and strongly bound hydrogen atoms play the most important role.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Chemisorption of methanol on different platinum electrodes (smooth and rough polycrystalline, monocrystalline, and preferentially oriented), as studied by EMIRS

EMIR spectra of methanol electroadsorbates on smooth and rough polycrystalline, monocrystalline and preferentially oriented platinum electrodes are reported. The (100)-type preferred oriented platinum behaves approximately as Pt (100) single crystals. On electrodispersed platinum electrodes the poisoning phenomena due to CO adsorbates appear to be reduced as compared to smooth platinum electrodes. EMIRS results correlate well with the electrochemical behaviour of the different platinum electrodes for methanol electrooxidation.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada