Electrodes based on arrays of TiO₂ nanowires were prepared by template sol-gel synthesis with the goal of developing a hydrazine photoelectrochemical sensor. Experimental conditions were chosen so that the gelation reaction occurred inside the nanopores of track-etched polycarbonate membranes, with consequent filling with TiO₂ nanowires. Different procedures for the removal of the template were examined, in order to obtain arrays of self-standing TiO₂ nanowires. The nanowire arrays were bound to fluorine doped tin oxide substrates to produce handy photoelectrodes. The photocurrent recorded with the photoelectrodes in the presence of hydrazine showed significant dependence on the pollutant concentration. The development of a photoelectrochemical sensor for hydrazine detection in water samples, based on this principle, is presented.

Directing charge carriers: Highly site-selective metal deposition on semiconductor nanofibers is achieved through a synergetic effect between UV irradiation and strong electric fields. This coupling allows the generation of electron–hole pairs and drives them to the opposite extremities of the fibers, where they can react with redox species in solution. Such an electric-field-assisted photochemical process is suitable to the highly localized photodeposition of metals, leading to semiconductor Janus objects. In this paper, TiO₂ nanofibers are anisotropically functionalised by depositing gold at one tip of each fiber. (DOI: 10.1002/celc.201402161).