The reduction of the band gap of titania is critically important to fully utilize its photocatalytic properties.Two main strategies, i.e. doping and partial reduction of Ti(IV), are the main alternatives available to date.Herein, we report a new synthesis strategy based on one-pot co-condensation of in situ prepared polymetallic titanium-alkoxide complexes with titanium tetrabutoxide. Using this direct reaction, it is possible to introduce organic compounds in the anatase phase, causing site distortions in the crystalline structure of the network. By using this strategy, a yellow and a black titania have been produced, with the latter showing a remarkable photocatalytic activity under visible-light.

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This work reports on a new strategy to design low-temperature (≤ 200°C) sintered dye-sensitized solar cells (ltDSSCs) with enhanced charge collection efficiencies (coll), photoconversion efficiencies, and stabilities under continuous operation conditions. This is accomplished by integrating into the electrodes a new class of hybrid mesoporous Ru(II) complex-TiO2 nanoparticles (TiO2_Ru_IS), obtained by in-situ bottom-up construction of dyesensitized titania using the Ru(II) N3 dye as building blocks. The most important assets of the TiO2_Ru_IS hybrid nanoparticles are i) a remarkable dye stability due to the integration of the dye within the anatase network and ii) a small nanoparticle size to enhance charge transport/collection processes. The latter is encouraging for tackling the two main bottlenecks in lt-DSSCs, that is, moderate efficiencies and low device stabilities. Our results evidence that devices with electrodes featuring a mixture of P25 and TiO2_Ru_IS show an enhanced charge transport and reduced electron recombination processes. The incorporation of TiO2_Ru_IS into the electrode leads to an increase ofcoll from 46% for P25 reference up to 60% for P25:TiO2_Ru_IS (80:20 wt%) device. As a final optimization, TiO2_Ru_IS was also applied as a top layer in a multi-layered device architecture, leading to coll of around 74%. The latter result in lt-DSSCs featuring efficiencies of 8.75% and lifetimes of 600 h under device operation conditions.

The nature of copper species of a series of alumina-supported copper samples was investigated by the kinetics of reduction, x-ray photoelectron spectroscopy, temperature-programmed desorptiob-mass spectrometry of chemisorbed NO and infrared spectroscopy of chemisorbed NO and CO probes. The role of these copper species was also examined in the catalytic decomposition of NO. The surface properties of copper were found to depend strongly on both Cu loading and calcination treatment. At Cu contents as low as 0.6 wt.%, Cu2+ ions form a well-dispersed interacting phase at the alumina surface, which upon calcination forms a surface spinel CuAl,O,. At copper contents up to 3.2 wt.%, both the surface spinel CuAl,O, and a segregated CuO phase were clearly distinguished. The partial reduction of these species upon thermal treatment under high vacuum, the ability of the surface sites to chemisorb NO and CO probes and their implications in the catalytic decomposition of NO are discussed.