On the behavior of modified TiO_2 nanotubes for a photoanode-driven photoelectrochemical reduction of CO_2

摘要

Chemical reduction of CO_2 is thermodynamically feasible only in the presence of strong reducing agents. Photoelectrochemical (PEC) reduction represents one of the possible alternatives: this technique may be considered "green" when solar energy and water are used to drive the process, like in natural photosynthesis. Different system configurations and different experimental conditions are needed, depending on the use of photosensitive material as cathode, anode or both in the PEC cell. In the present paper we investigated the possibility to use a photoanode-driven PEC cell, in which a metal was used as cathode, while the anode material was a nanotubular structure of TiO_2. The photocatalytic performance of the anode was improved by deposition of tungsten oxide. Electrodeposition was performed both by potential step (PST) and pulse potential technique (PPT). Different morphology of the deposit was obtained and, in turn, different performance was measured in terms of photocurrent at the related samples.