Surface Characterization of Ga2O3−TiO2 and V2O5/Ga2O3−TiO2 Catalysts

Synthesis and characterization of V2O5-Ga2O3 photocatalysts and their application on the photocatalytic reduction of CO2

The photocatalytic reduction of carbon dioxide (CO₂) to produce methanol (CH₃OH) is a promising strategy for producing clean energy. The catalyst, the aqueous medium, and the UV light are key parameters for the formation of the most relevant pair (e^-/h⁺) and the specific selectivity towards the desired product (methanol). The use of Ga₂O₃ and V₂O₅ in the photocatalytic reduction of CO₂ to produce methanol has been little studied. However, the combination of these oxides is important to generate synergies and decrease the band energy, enhancing the photocatalytic activity in CO₂ reduction. In this work, V₂O₅-Ga₂O₃ combined photocatalysts have been prepared and investigated for the photocatalytic reduction of CO₂. These photocatalysts were characterized by spectroscopic and microscopic techniques. The results showed that textural properties such as surface area and morphology do not influence the photocatalytic activity. However, species such as Ga2p_3/2 and Ga2p_1/2 identified by XPS enhanced the photocatalytic activity, most likely due to the formation of vacancies and the reduction of the bandgap in the combined oxides, as compared to single oxides. The contribution of these factors in pair interactions (e^-/h⁺) with CO₂ to generate methanol is demonstrated.

Enhanced Photocatalytic Activity of TiO2 Modified with GaI toward Environmental Application

Gallium (Ga) ion-doped TiO₂ (Ga-TiO₂) nanocomposite with small particle size (9-10 nm) and high surface area (104 m²/g) has been easily synthesized via sol-gel method at low temperature by using low-valent GaI as a doping precursor. The structural and morphological characterization of Ga-TiO₂ was carried out with standard analytical and spectroscopic techniques. Ga doping into the TiO₂ matrix inhibited a phase transformation from anatase to rutile (photocatalytically inactive) form, even at a higher temperature of 750 °C. Finally, Ga-TiO₂ nanocomposite showed high photocatalytic activity and exhibited 97% degradation of acid violet 63 dye within 60 min. The dye degradation rate constant was calculated as 1.6 × 10^-1 and 1.4 × 10^-1 min^-1 under UV and white light irradiation, respectively, which is higher, as compared to the previously reported Ga-TiO₂ composites to date.

Efficient selective 4-aminophenol sensing and antibacterial activity of ternary Ag2O3·SnO2·Cr2O3 nanoparticles

The electrochemical oxidation of 4-AP based on Ag₂O₃·SnO₂·Cr₂O₃ NPs/binder/GCE sensor.

Catalytic performance of gallium oxide based-catalysts for the propane dehydrogenation reaction: effects of support and loading amount

Ga₂O₃-based catalysts supported on different supports (ZSM-5, SBA-15, γ-Al₂O₃ and SiO₂) were prepared, and the effects of supports and Ga₂O₃ content (1–9 wt%) on their catalytic performance for the propane dehydrogenation reaction were discussed.

Dehydrogenation of propane over a hydrothermal-synthesized Ga2O3–Al2O3 catalyst in the presence of carbon dioxide

Hydrothermal-synthesized Ga₂O₃–Al₂O₃ catalysts showed superior activity for the dehydrogenation of propane in the presence of carbon dioxide.

Preparation and characterization of Ni-doped TiO2 materials for photocurrent and photocatalytic applications

Different amounts of Ni-doped TiO(2) (Ni = 0.1 to 10%) powders and thin films were prepared by following a conventional coprecipitation and sol-gel dip coating techniques, respectively, at 400 to 800°C, and were thoroughly characterized by means of XRD, FT-IR, FT-Raman, DRS, UV-visible, BET surface area, zeta potential, flat band potential, and photocurrent measurement techniques. Photocatalytic abilities of Ni-doped TiO(2) powders were evaluated by means of methylene blue (MB) degradation reaction under simulated solar light. Characterization results suggest that as a dopant, Ni stabilizes TiO(2) in the form of anatase phase, reduces its bandgap energy, and adjusts its flat band potentials such that this material can be employed for photoelectrochemical (PEC) oxidation of water reaction. The photocatalytic activity and photocurrent ability of TiO(2) have been enhanced by doping of Ni in TiO(2). The kinetic studies revealed that the MB degradation reaction follows the Langmuir-Hinshelwood first-order reaction relationship.

Structural Characterization of Nanosized CeO2−SiO2, CeO2−TiO2, and CeO2−ZrO2 Catalysts by XRD, Raman, and HREM Techniques

Structural characteristics of nanosized ceria-silica, ceria-titania, and ceria-zirconia mixed oxide catalysts have been investigated using X-ray diffraction (XRD), Raman spectroscopy, BET surface area, thermogravimetry, and high-resolution transmission electron microscopy (HREM). The effect of support oxides on the crystal modification of ceria cubic lattice was mainly focused. The investigated oxides were obtained by soft chemical routes with ultrahighly dilute solutions and were subjected to thermal treatments from 773 to 1073 K. The XRD results suggest that the CeO(2)-SiO(2) sample primarily consists of nanocrystalline CeO(2) on the amorphous SiO(2) surface. Both crystalline CeO(2) and TiO(2) anatase phases were noted in the case of CeO(2)-TiO(2) sample. Formation of cubic Ce(0.75)Zr(0.25)O(2) and Ce(0.6)Zr(0.4)O(2) (at 1073 K) were observed in the case of the CeO(2)-ZrO(2) sample. Raman measurements disclose the fluorite structure of ceria and the presence of oxygen vacancies/Ce(3+). The HREM results reveal well-dispersed CeO(2) nanocrystals over the amorphous SiO(2) matrix in the cases of CeO(2)-SiO(2), isolated CeO(2), and TiO(2) (anatase) nanocrystals, some overlapping regions in the case of CeO(2)-TiO(2), and nanosized CeO(2) and Ce-Zr oxides in the case of CeO(2)-ZrO(2) sample. The exact structural features of these crystals as determined by digital diffraction analysis of HREM experimental images reveal that the CeO(2) is mainly in cubic fluorite geometry. The oxygen storage capacity (OSC) as determined by thermogravimetry reveals that the OSC of the mixed oxide systems is more than that of pure CeO(2) and is system dependent.