Search

Abstract: A series of nanosized W,N-co-doped anatase TiO2 catalysts with different dopant contents has been prepared by a microemulsion method and examined in the sunlight selective photo-oxidation of toluene and styrene. The activity results have been correlated with structural, electronic, and surface examinations of the catalysts done with the help of XRD–Rietveld, N2 physisorption and NH3 chemisorption–calorimetry, XPS, Infrared, and UV–visible spectroscopies. Irrespective of the reaction, a consistent reaction rate enhancement with respect to titania (nano-TiO2, P25) references and W-doped TiO2 systems is observed for single-phase anatase W,N-co-doped samples. This is likely linked with the decrease of the band gap energy decrease and results from a combined W–N cooperative effect on structural properties of the anatase network. W,N simultaneous presence also makes a drastic effect on selectivity, maximizing the yield to partial oxidation products. This appears related with surface properties of the materials. [Copyright &y& Elsevier]

Cu/TiO 2 /SrTiO 3 hybrid structures have been synthesized by the simple impregnation method from Cu/TiO 2 and SrTiO 3 systems. The structural and surface characterization stated that Cu/TiO 2 /SrTiO 3 composites form an effective covering of SrTiO 3 by Cu/TiO 2 . The heterostructured catalysts lead to an outstanding improved photoactivity for hydrogen production from methanol photoreforming that would be related with the efficient separation of charge pairs favored by the Cu/TiO 2 /SrTiO 3 heterojunction. The best photoproduction is attained for the 30 wt % SrTiO 3 heterojunction showing 81.7 mmol/g H 2 after 6 h (leading to an apparent quantum yield of ca 1%), 1.7 times higher than that of bare Cu/TiO 2 ., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

We report on a novel synthesis method, which produces NaY(MoO 4 ) 2 nanoparticles having an almost spherical shape and hydrophilic character. The procedure is also suitable for the preparation of NaY(MoO 4 ) 2 -based nanophosphors by doping this host with lanthanide cations (Eu 3+ , Tb 3+ and Dy 3+ ), which, under UV illumination, exhibit intense luminescence whose color is determined by the selected doping cation (red for Eu 3+ , green for Tb 3+ and yellow for Dy 3+ ). The effects of the cations doping level on the luminescent properties are analyzed in terms of emission intensities and luminescent lifetime, to find the optimum phosphors. Finally, the performance of these nanophosphors and that of the undoped system for the photocatalytic degradation of rhodamine B, used as a model compound, is also analyzed.

Understanding how a photocatalyst modulates its oxidation state, size, and structure during a photocatalytic reaction under operando conditions is strongly limited by the mismatch between (catalyst) volume sampled by light and, to date, the physicochemical techniques and probes employed to study them. A synchrotron micro-beam X-ray absorption spectroscopy study together with the computational simulation and analysis (at the X-ray cell) of the light-matter interaction occurring in powdered TiO 2 -based monometallic Cu, Ni and bimetallic CuNi catalysts for hydrogen production from renewables was carried out. The combined information unveils an unexpected key catalytic role involving the phase contact between the reduced and oxidized non-noble metal phases in all catalysts and, additionally, reveals the source of the synergistic Cu-Ni interaction in the bimetallic material. The experimental method is applicable to operando studies of a wide variety of photocatalytic materials., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Er-doped BiVO4 are synthesized by means of a surfactant free microwave assisted hydrothermal method having good photoactivities under sun-like excitation for the degradation of methylene blue. From the structural and morphological characterization, it has been stated that the presence of Er(3+) induces a slight stabilization of the tetragonal phase, probably due to its incorporation in the BiVO4 lattice. The best photocatalytic performances were attained for the samples with Er(3+) content higher than 3 at%. The occurrence of the Er(3+) doped tetragonal BiVO4 clearly induces higher photocatalytic activities. The existence of a luminescence process has been related with the enhanced photoactivity observed.