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The effect of reduced graphene oxide (rGO) content in boron-modified TiO 2 nanocrystalline films on their photocatalytic activity in phenol oxidation is investigated. Visible-light-active TiO 2 modified photoanodes were prepared by incorporating graphene sheets into the sol-gel reaction of B-TiO 2 , followed by depositing the reaction products on 304 stainless steel plates by dip-coating technique. Thin films obtained by in situ sol-gel synthesis were characterized by FESEM, GIXRD and UV-vis diffuse reflectance spectroscopy. FESEM examination showed cracked films due to the tensile stress generated by solvent evaporation. GIXRD results showed that boron in the films inhibits the growth of crystallites. Comparing to unmodified TiO 2 , B-TiO 2 /rGO showed a red shift in the band gap. The potentiodynamic anodic polarization measurements showed that graphene incorporation improved the photogenerated electron transport within the film, hence increasing the photocurrent. These enhancements are explained on the basis of the ability of graphene in promoting the charge carrier separation by transferring the photogenerated electrons from the illuminated photoanode to the substrate. The film B-TiO 2 /rGO obtained from the sol solution containing 0.03 wt/v% boron and 3 wt/v% graphene exhibited the highest photocurrent, which was 30 times larger compared with the photocurrent of TiO 2 film. Key words:Composite thin films, modified TiO 2 photoelectrode, graphene, electron transport, photoelectrocatalytic oxidation.Fotoánodos modificados con óxido de grafeno reducido para mejorar el rendimiento fotoelectrocatalítico de B-TiO 2 bajo luz visible ResumenSe investiga el efecto del contenido de óxido de grafeno reducido (rGO) en películas de TiO 2 modificadas con boro sobre su actividad fotocatalítica en la oxidación de fenol. Fotoánodos modificados de TiO 2 activos a la luz visible fueron preparados incorporando hojas de grafeno en la reacción sol-gel de B-TiO 2 , seguido por el depósito de los productos de la reacción sobre láminas de acero inoxidable 304 por la técnica dip-coating. Las películas delgadas obtenidas por síntesis sol-gel in-situ fueron caracterizadas por FESEM, GIXRD y espectroscopia de reflectancia difusa UV-vis. La observación por FESEM mostró películas agrietadas debido al estrés mecánico generado por la evaporación del solvente. Los resultados de GIXRD mostraron que el boro en las películas inhibe el tamaño de los cristalitos. Comparando con el TiO 2 , el dióxido de titanio modificado presentó un desplazamiento de la banda de energía prohibida hacia el rojo. Las mediciones de polarización anódica potenciodinámica mostraron que la incorporación de grafeno mejora el transporte de electrones fotogenerados dentro de las películas compuestas incrementando así la fotocorriente. Estas mejoras se explican en base a la habilidad del grafeno para facilitar la separación de portadores de carga, transfiriendo los electrones fotogenerados desde la película iluminada de B-TiO 2 hasta el sustrato. La película compuest...

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The photocatalytic degradation/adsorption process of the -blocker atenolol (ATL) under UV irradiation is described using two types of silver decorated catalysts: silver/titania and silver/titanates. The silver ions were reduced on the surface of TiO 2 -P25-Degussa using gallic acid. Silver/titanates were prepared by a microwave-assisted hydrothermal method using the silver/titania as the starting material to obtain the hydrogen titanate (H 2 Ti 3 O 7 ) structure with tubular morphology. These materials were characterized by X-ray diffraction, UV-Vis spectroscopy, N 2 physisorption, temperature programmed reduction, TEM, and FTIR spectroscopy. During the photocatalytic process, the ATL molecules were completely converted to amino-diol byproducts. It is the first time that these materials have been applied during the photocatalytic process in the degradation of pharmaceuticals products. The success of the silver nanoparticles (2 nm) consists of the homogeneous distribution over the surface of titanate nanotubes inhibiting the hole/electron recombination promoting the oxidation process. The Ag@H 2 Ti 3 O 7 with a concentration of silver as 1.0% shows the highest adsorption/degradation of ATL than the Ag@TiO 2 and the P25-Degussa. The great performance in the reuse test consists in the strong attachment of the silver nanoparticles on the titanium surface that inhibits the silver lixiviation during the photocatalytic tests.