In this study UiO-66 and UiO-66-NH 2 were synthesized by solvothermal method. The effect of preparation conditions on the quality of UiO-66-NH 2 was studied. The obtained material has been characterized by x-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimatric analysis (TGA), scanning electron microscopy (SEM) and nitrogen physisorption measurements (BET). The CO 2 and CH 4 physisorption measurements were carried out using a high pressure volumetric analyzer (Micromeritics HPVA-100). The results showed that the UiO-66-NH 2 of ball shape crystalline had been obtained and characterized by high surface area (BET) up to 876 m 2 g −1 , specific volume 0.379 cm 3 g −1 , pore radius 9.5 Å and thermal stability up to 673 K, respectively. The experiments indicated that in comparison with UiO-66 the addition of NH 2 is able to increase the CO 2 and CH 4 storage capacity at 1 bar and 303 K twice from 28.43 cm 3 g −1 up to 52 cm 3 g −1 and from 6.68 cm 3 g −1 to 11.1 cm 3 g −1 , respectively.

Thin layers of pure TiO 2 and TiO 2 doped by different amounts of Fe 2 O 3 have been prepared by the sol–gel method with tetraisopropyl orthotitanate and Fe(NO 3)3. Physico-chemical properties of catalysts were characterized by BET Adsorption, x-ray Diffraction (XRD), FE-SEM, as well as Raman and UV-Vis spectroscopy. The photocatalytic activity of the obtained materials was investigated in the reaction of complete oxidation of p-xylene in gas phase under the radiation of UV (λ=365 nm) and LED (λ=470 nm) lamps. It has been found that the particle size of all samples was distributed in the range 20–30 nm. The content of the rutile phase in Fe-doped TiO 2 samples varied in the range 6.8 to 41.8% depending on the Fe content. Iron oxide doped into TiO 2 enables the photon absorbing zone of TiO 2 to extend from UV towards visible waves as well as to reduce its band gap energy from 3.2 to 2.67 eV. Photocatalytic activities of the TiO 2 samples modified by Fe 3+ have been found to be higher than those of pure TiO 2 by about 2.5 times.

A series of Ni/SBA-15 catalysts was prepared by impregnation method. Effect of NiO content (3060 mass%), calcination time (0.52 h at 800°C), and reduction time (12 h at 800°C) on catalytic performance in combined steam and CO 2 reforming of CH 4 (CSCRM) was studied. N 2 physisorption measurements, powder X-ray diffraction, Hydrogen temperature-programmed reduction, CO 2-temperature-programmed desorption, and transmission electron microscopy were used to investigate physico-chemical properties of the catalysts. The catalytic performance of Ni/SBA-15 in CSCRM was assessed in the temperature range of 550800°C. The results revealed suitable time for calcination and reduction being 0.5 h and 1.5 h, respectively. After these treatments, 40 mass% NiO/SBA-15 catalyst was more active and exhibited higher activity than others. At 750°C, conversion of CH 4 and CO 2 on this catalyst in CSCRM was 91.05% and 78.11%, respectively. High surface area, better reducibility, and good affinity with CO 2 contribute to the high performance of this catalyst.

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β-MoO 3 was successfully synthesized from all commercial materials using a fast, effective and simple method and characterized by differential scanning calorimetry, x-ray powder diffraction, field emission scanning electron microscopy, infrared and Raman spectroscopy. The prepared sample was highly active and selective to formaldehyde formation from methanol over a wide range of reaction temperatures. β-MoO 3 catalyst also exhibited stable methanol conversion and formaldehyde selectivity at around 84% and over 95% respectively for over 15 operating hours at 320 °C. However, it may be deactivated at elevated reaction temperature due to transformation of metastable to stable phase. It was revealed that the prepared catalyst maintains its high selectivity to formaldehyde during deactivation. This can be considered as an advantage of the prepared MoO 3 catalyst in comparison with the industrial one.

In this work, 31.4 wt.% Ni/SBA-15 (Ni/SBA-15) nonpromoted and alkalized with ammonia solution and by MgO promoter catalysts were prepared and used for combined steam and CO2 reforming of CH4 (bireforming). Effect of concentration of ammonia solution (NH3(aq)) (10–25 vol.%) and Mg content (3–12 wt.%) on the properties of the Ni/SBA-15 catalysts was investigated by low-angle and powder X-ray diffraction (XRD), N2-BET isothermal adsorption, SEM, TEM, EDS mapping, H2-TPR, and CO2-TPD methods. The performance of the catalysts in bireforming was assessed in the temperature range of 550–800°C. The enhancement of dispersion of NiO particles, reducibility, and basicity of alkalized Ni/SBA-15 catalysts were responsible for improving the catalytic performance of this catalyst. The results revealed that the Ni/SBA-15 treated with 15-25% NH3(aq) solution and promoted with 3-9% Mg exhibited high activity for CH4 conversion. Meanwhile, Ni6Mg/SBA-15 showed the highest CO2 conversion. Among tested catalysts, Ni/SBA-15-20NH3 and Ni9Mg/SBA-15 samples had an almost equal activity with a CH4 conversion of nearly 97% and a CO2 conversion of about 84% at 700°C thanks to its moderate affinity with both CO2 and CH4. However, the H2/CO ratio of the product mixture remained at 2.02 on the Ni/SBA-15-20NH3 catalyst and almost 1 on the Ni9Mg/SBA-15 sample. These results might be related to the fact that the alkalization of the Ni/SBA-15 catalyst by NH3(aq) solution had an advantage over using MgO because side reactions were unlikely to occur.

By dip-coating technique the thin films of nano-photocatalysts TiO2, Cr-doped TiO2, LaBO3 perovskites (B  =  Fe, Mn, and Co) prepared by sol-gel method, and UiO66-NH2 prepared by a solvothermal were obtained and employed for gas phase degradation of p-xylene. Physicochemical characteristics of the catalysts were examined by the methods of BET, SEM, TEM, XRD, FT-IR, TGA, Raman and UV–vis spectroscopies. The thickness of film was determined by a Veeco-American Dektek 6M instrument. The activity of catalysts was evaluated in deep photooxidation of p-xylene in a microflow reactor at room temperature with the radiation sources of a UV (λ  =  365 nm) and LED lamps (λ  =  400–510 nm). The obtained results showed that TiO2 and TiO2 doped Cr thin films was featured by an anatase phase with nanoparticles of 10–100 nm. Doping TiO2 with 0.1%mol Cr2O3 led to reduce band gap energy from 3.01 down to 1.99 eV and extend the spectrum of photon absorption to the visible region (λ  =  622 nm). LaBO3 perovkite thin films were also featured by a crystal phase with average particle nanosize of 8–40 nm, a BET surface area of 17.6–32.7 m2 g−1 and band gap energy of 1.87–2.20 eV. UiO66-NH2 was obtained in the ball shape of 100–200 nm, a BET surface area of 576 m2 g−1 and a band gap energy of 2.83 eV. The low band gap energy nano-photocatalysts based on Cr-doped TiO2 and LaBO3 perovskites exhibited highly stable and active for photo-degradation of p-xylene in the gas phase under radiation of UV–vis light. Perovskite LaFeO3 and Cr–TiO2 thin films were the best photocatalysts with a decomposition yield being reached up to 1.70 gp-xylene/gcat.

In this investigation, the thin film of degussa P25 was obtained by dip coating method and calcined at 450 °C for 2 h (P25-450-2) and used as photocatalyst for gas-phase photooxidation of xylene. The physico-chemical properties of calcined P25-450-2 powder was studied by the methods of BET adsorption, XRD, FTIR, UV–vis, Raman spectroscopies, SEM, TEM, carbon dioxide temperature-programmed desorption . The thickness of the film was determined on the Alpha Step IQ KLA—Ctencor equipment and the point of zero charge (PZC) of the sample was determined by salt addition method. P25-450-2, having a band gap of 3.155 eV, is advisable to use UV lamps in photocatalytic reactions. The kinetics of gas-phase photooxidation of xylene reaction on the thin films of P25-450-2 under UV illumination was studied using a gradientless flow circulating system at atmospheric pressure and 40 °C. The obtained results showed that the kinetics of the given reaction should be written by fractional equations describing the dependence of the reaction rate on the concentration of adsorbed molecules of xylene and oxygen, dissociative adsorbed water vapor, and also on the total intensity of light. The reaction was proposed to follow the Langmuir-Hinshelwood mechanism.