Spectroscopy electrolysis product detection

Although product analysis seems essential for the clarification of complex ET processes involving biological molecules, only few attempts have so far been made. Ohde et al. [15,35] conducted bulk electrolysis to determine spectrophotometrically some redox products of interfacial ET reactions. Recently, Sawada et al. [39] have developed a microflow coulometric cell with a hydrophobic membrane-stabilized O/W interface. This microflow cell can accomplish complete electrolysis, and thus determination of the number of electrons for complex ET reactions at O/W interfaces. Also, its use for an on-line spectrophotometric detection of electrolysis products was made [43]. Figure 8.5 shows the spectmm change of the electrolyzed solution for the ET between Fc in NB and Fe(CN)e in W. When relatively small potentials were applied to the microflow cell, Fc" could be detected in the electrolyzed solution. The characteristic absorbance peak at 620 nm showed an undoubted existence of Fc+ in the W phase as the electrolysis product. This result would also support the IT mechanism. In situ UV-visible spectroscopy [44 46] also deserves attention for its usefulness in product analysis and clarification of reaction mechanisms. 

Also, nitrate electroreduction is estimated by prolonged electrolysis by controlling either the potential or the current. The electrode performance for nitrate electrolysis is evaluated by measuring the nitrate destruction yield, the current efficiency, the selectivity and the specific energy consumption [15, 16]. During electrolysis, products can be accurately detected and quantified by ionic/gaseous chromatography, and UV-Vis spectroscopy. 

V vs. RHE in agreement with previous studies by DBMS, infrared spectroscopy and gas chromatography. Moreover, Iwasita and Pastor have detected some traces of methane at low potentials. From prolonged electrolysis experiments and in situ infrared reflectance spectroscopy, the main reaction products and intermediates involved in ethanol electro-oxidation on a platinum catalyst have been determined CO and CH3CO species as adsorbed intermediates, CH3CHO as intermediate and final product, CH3COOH, CO2 and CH4 as final products. 

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