Indirect electroreduction of o-nitrophenol to o-aminophenol on titanium dioxide coated titanium electrodes

Silver supported on titania as an active catalyst for electrochemical carbon dioxide reduction

Although significant research efforts have focused on the exploration of catalysts for the electrochemical reduction of CO2 , considerably fewer reports have described how support materials for these catalysts affect their performance, which includes their ability to reduce the overpotential, and/or to increase the catalyst utilization and selectivity. Here Ag nanoparticles supported on carbon black (Ag/C) and on titanium dioxide (Ag/TiO2 ) were synthesized. In a flow reactor, 40 wt % Ag/TiO2 exhibited a twofold higher current density for CO production than 40 wt % Ag/C. Faradaic efficiencies of the 40 wt % Ag/TiO2 catalyst exceeded 90 % with a partial current density for CO of 101 mA cm(-2) ; similar to the performance of unsupported Ag nanoparticle catalysts (AgNP) but at a 2.5 times lower Ag loading. A mass activity as high as 2700 mA mgAg (-1)  cm(-2) was achieved. In cyclic voltammetry tests in a three-electrode cell, Ag/TiO2 exhibited a lower overpotential for CO2 reduction than AgNP, which, together with other data, suggests that TiO2 stabilizes the intermediate and serves as redox electron carrier to assist CO2 reduction while Ag assists in the formation of the final product, CO.

Fixation of CO2 by electrocatalytic reduction and electropolymerization in ionic liquid-H2O solution

The electrocatalytic synthesis of low-density polyethylene (LDPE) from carbon dioxide on a nanostructured (ns)TiO2 film electrode was investigated by controlled potential electrolysis in a solvent mixture of water and the ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMI]BF4) at room temperature under ambient pressure. Under these conditions, the nsTiO2 film is remarkably efficient and selective for the electroreduction of CO2. The current efficiency for the formation of the electrolytic product is about 8-14% at -1.50 V (vs SCE). The electrocatalytic activity of the electrode in the electrochemical reduction of CO2 was investigated by cyclic voltammetry (CV), and the probable electrode reaction mechanism is discussed.