Many studies are focused on the development of materials for converting carbon dioxide into multicarbon oxygenates such as methanol and ethanol, because of their higher energy density and wider applicability. In this work, TiO 2 nanotubes (NT/TiO 2 ) were modified with Cu x O nanoparticles in order to investigate the contribution of different ratio of Cu 2 O/CuO and its distribution over NT/TiO 2 for CO 2 photoelectro-conversion to methanol. The photoelectrodes were built by anodization process to obtain NT/TiO 2 layer, and the decoration with Cu x O hybrid system was carried out by electrodeposition process, using Na 2 SO 4 or acid lactic as electrolyte, followed by annealing at different temperatures. X-ray photoelectron spectroscopy analysis revealed the predominance of Cu +1 and Cu +2 at 150°C and 300°C, respectively. X-ray diffraction and scanning electron microscopy indicated that under lactic acid solution, the oxide nanoparticles exhibited small size, cubic shape, and uniform distribution on the nanotube wall. While under Na 2 SO 4 electrolyte, large nanoparticles with two different morphologies, octahedral and cubic shapes, were deposited on the top of the nanotubes. All modified electrodes converted CO 2 in methanol in different quantities, identified by gas chromatograph. However, the NT/TiO 2 modified with CuO/Cu 2 O (80:20) nanoparticles using lactic acid as electrolyte showed better performance in the CO 2 reduction to methanol (0.11 mmol L −1 ) in relation to the other electrodes. In all cases, a blend among the structures and nanoparticle morphologies were achieved and essential to create new site of reactions what improved the use of light irradiation, minimization of charge recombination rate and promoted high selectivity of products.Keywords CO 2 photoelectroreduction . Hybrid TiO 2 -Cu x O photocatalysts . p-n heterojunction . Electrolyte design . Methanol formation

No abstract

No abstract

Ti-Cu alloys could be used as a substrate to produce photoelectrode pn-heterojunctions to increase copper stability and consequently to improve photoconversion of CO2. Cu–Ti–O films were grown by anodizing directly of Ti–x%at.Cu (x= 0.5, 5.5, 10 and 50) and after these alloys were submitted different kinds heat treatment (annealing or quenching) to compare a directly influence of presents phases in nanotubes alloy substrate after it preparation by voltaic arc melting following a annealed or rapid quenching as heat treatment. All films presented TiO2 and copper dioxides in its compositions. These electrodes showed higher absorbance in visible light, anodic current for less copper alloy cathodic current equiatomic composition and copper stability for all cases due cu atomic insertion inside TiO2 crystal lattice and sharing oxygen atomic. The cathodic current varied in function of Cu concentration in the alloy.

No abstract