Evonik P25 Research Articles

Development of photocatalytic titanium dioxide membranes for degradation of recalcitrant compounds

BACKGROUND Immobilization of TiO2 photoactive nanoparticles on a nanofiltration membrane without loss of permselectivity properties is currently a challenge. In this study, immobilization of TiO2 nanoparticles on a ceramic commercial membrane surface by direct current reactive magnetron sputtering was addressed. The best membrane was compared with an unmodified membrane and a membrane modified by a generic chemical–physical method in terms of membrane permselectivity and photocatalytic properties. RESULTS Magnetron sputtering was able to achieve similar photocatalytic activity to the chemical–physical method, where Evonik P25 TiO2 nanoparticles were used, while maintaining membrane rejection and permeability. The layer formed by magnetron sputtering exhibits uniformly distributed nanostructured columns, aligned perpendicularly to the membrane surface. Furthermore, the membrane hydrophilicity increase achieved is promising for fouling control. A shorter sputtering time and distance between the titanium target and the membrane were preferable to effectively degrade the pesticides diuron and chlorfenvinphos. Under optimum sputtering conditions, 95% and 78% increases were attained for the degradation of diuron and chlorfenvinphos, respectively, compared with the unmodified membrane. CONCLUSION The photocatalytic membranes developed are potential candidates for the simultaneous retention and photocatalytic degradation of recalcitrant micropollutants. However, if the purpose is to retain low molecular weight molecules, retentive properties should be improved. © 2016 Society of Chemical Industry

Micro-mesoporous N-doped brookite-rutile TiO2 as efficient catalysts for water remediation under UV-free visible LED radiation

N-doped brookite-rutile catalysts were prepared using the sol-gel method with different nitrogen precursors, namely urea (CH4N2O), propionitrile (C3H5N), ammonium hydroxide (NH4OH), ammonium nitrate (NH4NO3) and ethylene diamine (C2H8N2). Testing the photoactivity of the prepared catalysts with 4-nitrophenol revealed that ammonium nitrate was the best doping agent with a nominal N-content of 0.8% (w/w), yielding a 5-fold increase in the pseudo-first order constant of 4-nitrophenol disappearance and a 3-fold increase in the pseudo-first order constant of TOC disappearance, with respect to undoped TiO2, when irradiated with LED visible light (>425nm).In the same experimental conditions, commercial catalysts such as Evonik P25 and mixtures of commercial rutile and brookite failed to work. XRD allowed to identify two crystal phases, i.e. brookite and rutile, and to show that the most active catalyst had the highest brookite and lowest amorphous content, along with the largest rutile crystallites. Through HRTEM, the morphology and crystallinity were further investigated: brookite particles were much smaller and roundish with respect to rutile and the intimate contact between the two phases was also well highlighted. N-doping did not produce oxygen vacancies as shown by Raman spectroscopy; thus, the doping can be considered interstitial rather than substitutional. Surface hydroxylation did not promote oxidation ability, as revealed by TGA-DTA: the most reacting catalyst is the least hydroxylated one. BET revealed that the samples are partially mesoporous (type IV hysteresis), although no template/surfactant was used, and the pore size and volume seemed to affect their activity. UV-vis DRS allowed to extrapolate the band gaps, only slightly narrower for N-doped samples, which, however, showed a pronounced absorption of visible radiation compared to undoped TiO2. Photoluminescence showed that the emission due to electron-hole recombination decreases with the N-loading, eventually reaching a minimum plateau for doping amounts just above the optimal one.

Advances on the synthesis of porous TiO2 coatings by anodic spark oxidation. Photocatalytic reduction of Cr(VI)

Porous TiO2 coatings were obtained by anodic oxidation in spark discharge conditions, varying the range of current density (200–3000 A m−2) and the electrolyte concentration (H2SO4; 1 and 4 M). The samples were characterized by SEM, XRD and DRS. The photocatalytic activity was evaluated using the Cr(VI)/EDTA reductive system to find the optimal conditions for a high photocatalytic activity. A higher electrolyte concentration increased the pore diameter, the porous fraction and the coating thickness and, consequently, the photocatalytic activity; a higher current density improved the performance of coatings. A relationship between the anatase fraction and the photocatalytic activity of the samples was demonstrated, with a maximum activity close to 0.65 anatase fraction. The thermal treatment of the anodic coatings improved also the photocatalytic activity, without changes on neither the morphology nor the anatase fraction. The maximum Cr(VI) transformation achieved by the most active coating was 89.1% while a coating prepared with Evonik P25 achieved only 69.9%. The obtained TiO2 anodic coatings present great potential for application in heterogeneous photocatalysis processes in water and wastewater treatment as supported photocatalysts.

Large Scaled Synthesis of Heterostructured Electrospun TiO2/SnO2 Nanofibers with an Enhanced Photocatalytic Activity

Heterostructured TiO2/SnO2 fibrillar nanocomposites were synthesized by using electrospinning technology with the setup composed of a syringe pump with two parallel syringes on it and a rotating collector. The heterojunctions were formed between TiO2 and SnO2 nanofibers fast and efficiently on a large scale, after the fiberizing carrier polyvinylpyrrolidone (PVP) on the as-spun composite nanofibers was burnt away at 500°C. The samples were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflection spectroscopy (DRS), and photoluminescence spectra (PL), respectively. The results indicated that two kinds of small nanofibers with different diameters were interconnected to form heterojunctions. Photocatalytic tests displayed that the heterostructured TiO2/SnO2 nanofibers exhibited a much higher degradation rate of methylene blue (MB), rhodamine B (RhB), and 4-chlorophenol (4-CP) than that of bare TiO2 nanofibers or Evonik P25 under UV light irradiation. The enhanced photocatalytic activity could be attributed to the effective charge separation derived from the coupling effect of TiO2 and SnO2 nanocomposites.

Quantum tunneling injection of hot electrons in Au/TiO2 plasmonic photocatalysts.

Visible light absorption of plasmonic Au nanoparticles supported on semiconductor TiO2 leads to injection of their photoactivated "hot electrons (ehot-)" into the TiO2 conduction band. This charge separation facilitates several oxidation and reduction reactions. These plasmonic systems, however, suffer from low quantum yields because the Schottky barrier created at the Au-TiO2 interface suppresses ehot- injection. Here we report that Au nanoparticles supported on the anatase particles isolated from Degussa (Evonik) P25 TiO2 promote ehot- injection with much higher efficiency than those supported on other commercially-available TiO2 and catalyze aerobic oxidation with very high quantum yield (7.7% at 550 nm). Photoelectrochemical and spectroscopic analysis revealed that the number of Ti4+ atoms located at the Au-TiO2 interface is the crucial factor. These Ti4+ atoms neutralize the negative charge of the Au particles and create a Schottky barrier with narrower depletion layer. This facilitates efficient ehot- injection by "quantum tunneling" through the Schottky barrier without overbarrier energy. The ehot- injection depends on several factors, and loading of 2 wt% Au particles with 3.5-4 nm diameters at around room temperature exhibits the highest activity of plasmonic photocatalysis.

Amoxicillin photodegradation by nanocrystalline TiO2

Nanocrystalline TiO2, synthesized by sol-gel route and characterized by XRPD, BET and SEM measurements, was applied in the photocatalytic degradation of amoxicillin, using an Osram Ultra-Vitalux? lamp as the light source. Amoxicillin is a semi-synthetic penicillin type antibiotic active against a wide range of grampositive and a limited range of gram-negative organisms. The continuous release of antibiotics and their persistence in the environment may result in serious irreversible effects on aquatic and terrestrial organisms. Heterogeneous catalysis, which uses catalysts like TiO2, is a promising route for the degradation of organic pollutants including antibiotics. The effects of initial concentration of catalyst, initial salt concentration (NaCl and Na2SO4), ethanol and pH on the photocatalytic degradation of amoxicillin were studied. The mineralization of amoxicillin was analyzed by ion chromatography as well as by total organic analysis. The catalytic properties of nanocrystalline TiO2 were compared to Evonik P25 catalyst.

Photocatalytic and photoelectrochemical properties of hierarchical mesoporous TiO2 microspheres produced using a crown template

Abstract Mesoporous hierarchical TiO 2 microspheres (MSs) with a size of 1–3 μm and an average pore size of 12.2–17.5 nm composed of smaller spherical 40–60-nm aggregates of discrete ∼10-nm anatase nanocrystals (NCs) were produced by the sol-gel transformation of Ti(IV) tetra butoxide in the presence of dibenzo-18-crown-6. Photocatalytic and photoelectrochemical properties of the TiO 2 MSs were studied in several processes important for the sustainable light-to-energy conversion and environmental photocatalysis. In particular, the TiO 2 MSs were found to be a much more efficient photocatalyst of the water reduction and the gas-phase oxidation of benzene and ethanol than irregularly aggregated mesoporous TiO 2 and a benchmark Evonik P25 TiO 2 . The MSs also revealed an advanced photoelectrochemical activity. The most probable reasons for the high photochemical activity of the MSs are (i) the effect of multiple scattering and reflection of light passing through the MSs that increases the probability of light absorption and (ii) the electron transport through the framework of interconnected loosely aggregated anatase NCs that results in suppression of the electron-hole recombination. In the photoelectrochemical cells based on the MS/CdS heterostructures the light is absorbed by a thin layer of the visible-light-sensitive CdS NCs and the advantages of the MSs are leveled off, the activity of TiO 2 as an electron transporting layer most probably limited by electrons leakage to the electrolyte.

Novel TiO2/C3N4 Photocatalysts for Photocatalytic Reduction of CO2 and for Photocatalytic Decomposition of N2O.

TiO2/g-C3N4 photocatalysts with the ratio of TiO2 to g-C3N4 ranging from 0.3/1 to 2/1 were prepared by simple mechanical mixing of pure g-C3N4 and commercial TiO2 Evonik P25. All the nanocomposites were characterized by X-ray powder diffraction, UV-vis diffuse reflectance spectroscopy, photoluminescence, X-ray photoelectron spectroscopy, Raman spectroscopy, infrared spectroscopy, transmission electron microscopy, photoelectrochemical measurements, and nitrogen physisorption. The prepared mixtures along with pure TiO2 and g-C3N4 were tested for the photocatalytic reduction of carbon dioxide and photocatalytic decomposition of nitrous oxide. The pure g-C3N4 exhibited the lowest photocatalytic activity in both cases, pointing to a very high recombination rate of charge carriers. On the other hand, the most active photocatalyst toward all the products was (0.3/1)TiO2/g-C3N4. The highest activity is achieved by combination of a number of factors: (i) specific surface area, (ii) adsorption edge energy, (iii) crystallite size, and (iv) efficient separation of the charge carriers, where the efficient charge separation is the most decisive parameter.

Photocatalytic, photoelectrochemical, and antibacterial activity of benign-by-design mechanochemically synthesized metal oxide nanomaterials

In the search for highly active and stable photocatalysts, significant efforts are devoted to find both new materials and innovative synthetic methods. In this study, an environmentally friendly and sustainable approach, dry reactive milling, was employed to synthesize two different semiconducting oxide nanomaterials, namely TiO2 and ZnO using polysaccharides as sacrificial templates. The as synthesized nanomaterials were characterized by powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, diffuse reflection UV-vis and Raman spectroscopy, and N2 adsorption tests. Their photocatalytic activity was tested in ethanol degradation, followed by gas chromatographic analysis. Photoelectrochemical measurements were performed to assess the optoelectronic properties and the antimicrobial activity of these photocatalysts was also tested under visible light irradiation. Overall, we found that the performance of the synthesized nanomaterials was comparable to the benchmark P25 EVONIK titania, with ZnO exhibiting a remarkably superior antibacterial activity against E. coli.

Reduction of nitrate by heterogeneous photocatalysis over pure and radiolytically modified TiO2 samples in the presence of formic acid

Heterogeneous photocatalytic reduction of nitrate (2mM) in the presence of formic acid (FA, 10mM) using pure and modified TiO2 samples under UV–vis irradiation was performed at pH 3, and the evolution of the intermediate and final products was analyzed. For this work, commercial samples (Evonik P25 and Cristal Global PC500 and PC10) were modified by γ-radiolysis with two noble metal nanoparticles known to behave differently in NO3− transformation, Ag and Pd. P25 was modified with Ag (0.5 and 2%w/w), while PC10 and PC500 were modified with Pd (1%w/w). The order of the photocatalytic activity of the materials for NO3− transformation was 2 Ag-P25>PC500>0.5 Ag-P25≈P25≫1 Pd-PC500>PC10>1 Pd-PC10. Nitrite formation was observed in all cases but at low amounts, and its concentration was negligible (≤1μM) after complete NO3− reduction. Ammonium was found as final product and remained in considerable amounts at the end of the irradiation. The nitrogen balance accounted for a large amount of non-identified nitrogen products formed during the photocatalytic reaction, probably N2 or NO; this amount was higher for the P25 and PC500 pure samples. The efficiency on the use of FA as donor was evaluated and PC500 was found to be the most efficient sample in this sense. A mechanism is proposed to clarify the still not well understood process of TiO2 heterogeneous photocatalytic transformation of nitrate, based on literature data and detected products.

Photocatalytic degradation of salicylic acid and caffeine emerging contaminants using titania nanotubes

Heterogeneous photocatalysis can be a suitable add-on process to conventional wastewater treatment methods aiming to the full degradation of emerging contaminants contributing to water pollution. This work examines the photo-degradation of two frequently detected emerging contaminants (caffeine and salicylic acid) using titanium dioxide nanotubular films (TNTs) so as commercial TiO2 nanoparticulate films (Evonik P25) for comparison. The TNT films were prepared by electrochemical anodization of titanium metal and reached lengths of 20μm, with a high growth rate (10μm/h). They present an open porous structure with large specific surface area suitable for efficient adsorption of the contaminants and formation of a large number of photocatalytic active sites. After calcination at 450°C, TNT films obtain the anatase crystal structure, absorb well in the UV range and present significant photocatalytic activity with high degradation rates for both examined emerging pollutants. Furthermore, they present small variability of their photocatalytic efficiency in a big range of the solutions pH values and under consecutive photocatalytic cycles, rendering them suitable at various wastewater treatment conditions.

TiO2 Processed by pressurized hot solvents as a novel photocatalyst for photocatalytic reduction of carbon dioxide

Anatase-brookite TiO2 photocatalysts were prepared by the sol-gel process controlled within reverse micelles and processing by pressurized hot solvents–water/methanol/water (TiO2(M)) and water/ethanol/water (TiO2(E)), as an unconventional alternative to common calcination. The main goal of this work was to prepare anatase-brookite mixtures by processing by two different alcohols (methanol and ethanol) and evaluate the influence of the alcohol on the photocatalytic activity. Prepared photocatalysts were characterized by organic elemental analysis, nitrogen physisorption, XRD, UV–vis, photoelectrochemical and spectroelectrochemical measurements and XPS. The prepared photocatalysts efficiency was tested on the photocatalytic reduction of carbon dioxide and compared with commercial TiO2 Evonik P25. Both prepared nanocomposites were more efficient towards methane production but Evonik P25 was the most efficient towards hydrogen generated through water splitting. The higher performance of anatase-brookite mixture towards methane production can be explained by (i) a higher photocatalytic activity of brookite than rutile; (ii) a large surface area of anatase-brookite composites enabling better carbon dioxide adsorption; (iii) the photoinduced electron transfer from the brookite conduction band to the anatase conduction band. On the other hand, a higher production of hydrogen in the presence of Evonik P25 is caused by a better charge separation in anatase-rutile than anatase-brookite phase compositions. TiO2(M) appeared more active than TiO2(E) in the photocatalytic reduction of carbon dioxide due to a lower density of defects created in the crystal lattice.

Keggin heteropolyacids supported on TiO2 used in gas-solid (photo)catalytic propene hydration and in liquid-solid photocatalytic glycerol dehydration

(Photo)catalytic propene hydration to 2-propanol and glycerol dehydration to acrolein were carried out by using Keggin heteropolyacids (HPAs) supported on TiO2. Binary materials have been prepared by impregnation of H3PW12O40, H3PMo12O40 and H4SiW12O40, on TiO2 Evonik P25. Moreover, a binary material consisting of H4SiW12O40 and TiO2 was prepared via a hydrothermal treatment and tested for the same reactions. All the materials were characterized by X-ray diffraction (XRD), scanning electron microscopy observations (SEM) coupled with energy dispersive X-ray (EDX) measurements, diffuse reflectance spectroscopy (DRS), Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR). The supported Keggin HPA species played a key role both for the catalytic and for the photo-assisted catalytic reactions due to their strong acidity and ability to form strong oxidant species under UV irradiation.

The amorphous phase in titania and its influence on photocatalytic properties

In the present work, we compare the photocatalytic activity (PCA) of titania samples normalized to the sample weight and specific surface area (SSA), and show a correlation between the PCA of titania catalysts with similar phase compositions and amorphous phase contents. In our studies, we used the commercial samples, P25 Evonik (formerly Degussa), Hombikat UV100, and pre-synthesized mesoporous titania. Catalysts with a significant amorphous content were annealed and processed by partial dissolution in acid and included in the analysis. PCA was measured by methyl orange (MO) photodegradation in an aqueous catalyst suspension under high-pressure Hg bulb illumination and the pH was controlled using phosphate buffer (pH 6.9). The weight percentage of the amorphous phase was determined using reference intensity ratios (RIR) for X-ray diffraction patterns of the titania samples measured with crystalline silicon additives. The reproducibility of the proposed method was demonstrated by measuring the amorphous content in mixtures of the sample and XRD-amorphous titania. The contributions of amorphous titanium oxohydroxides TiO2−0.5n(OH)n ·xH2O and water physically adsorbed to the amorphous phases were distinguished by thermogravimetric analysis. The obtained results show that the PCA of the titania samples decreases with the weight percentage of the amorphous phase, as low as 5% of the PCA of P25 in the case of ωAm(TiO2)>25%. It was demonstrated that the partial removal of the amorphous phase by annealing or dissolution in nitric acid leads to a significant increase of PCA.

Supported H3PW12O40 for 2-propanol (photo-assisted) catalytic dehydration in gas-solid regime: The role of the support and of the pseudo-liquid phase in the (photo)activity

Catalytic and photocatalytic 2-propanol dehydration was carried out by using a supported Keggin heteropolyacid H3PW12O40 (PW12). Binary materials were prepared by impregnation and/or solvothermal treatment by using commercial supports: SiO2 (Mallinckrodt), TiO2 (Evonik P25) and multiwall carbon nanotubes (Sunnano) or home solvothermically prepared SiO2 and TiO2. All the materials have been characterized by X-ray diffraction (XRD), scanning electron microscopy observations (SEM) coupled with EDX microanalysis, specific surface area measurements, diffuse reflectance spectroscopy (DRS), FTIR and Raman spectroscopy. (Photo)catalytic 2-propanol dehydration was studied in gas-solid regime by using a continuous (photo)reactor working at atmospheric pressure and 80°C. FTIR spectra of the gas-phase over the PW12-support composites, where 2-propanol had been previously adsorbed, were recorded. Propene and diisopropyl ether were the main reaction products. For the continuous photo-assisted runs the reactor was also illuminated with UV light. The apparent activation energy of 2-propanol catalytic and photocatalytic dehydration was determined in the range 60–120°C.The irradiance increased significantly the dehydration reaction rate. Important differences were observed between the different supported materials. The Keggin heteropolyacid species played a key role both for the catalytic and the photo-assisted catalytic reactions; in fact, the acidity of the cluster accounts for the catalytic role, whereas both the acidity of the cluster and the oxidant ability of PW12 were responsible for the increase of the reaction rate of the photo-assisted catalytic reaction. Moreover, the photo-generated electrons on the solid semiconductor conduction band can account for a further increase of the reaction rate, when the heteropolyacid was supported on TiO2. Formation of a pseudo-liquid phase played an important role to determine the (photo)activity.

High photocatalytic activity of mixed anatase-rutile phases on commercial TiO2 nanoparticles

Titanium dioxide (TiO2) is well-known as an active photocatalyst for degradation of various organic pollutants. Over the years, a wide range of TiO2 nanoparticles with different phase compositions, crystallinities, and surface areas have been developed. Due to the different methods and conditions used to synthesize these commercial TiO2 nanoparticles, the properties and photocatalytic performance would also be different from each other. In this study, the photocatalytic removal of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5- trichlorophenoxyacetic acid (2,4,5-T) was investigated on commercial Evonik P25, Evonik P90, Hombikat UV100 and Hombikat N100 TiO2 nanoparticles. Upon photocatalytic tests, it was found that overall, the photocatalytic activities of the P25 and the P90 were higher than the N100 and the UV100 for the removal of both 2,4-D and 2,4,5-T. The high activities of the P25 and the P90 could be attributed to their phase compositions, which are made up of a mixture of anatase and rutile phases of TiO2. Whereas, the UV100 and the N100 are made up of 100% anatase phase of TiO2. The synergistic effect of the anatase/rutile mixture was reported to slow down the recombination rate of photogenerated electron-hole pairs. Consequently, the photocatalytic activity was increased on these TiO2 nanoparticles.

Effect of calcination temperatures on the photocatalytic activities of commercial titania nanoparticles under solar simulator irradiation

In this study, the effect of calcination temperatures on the photocatalytic activity of commercial TiO2 photocatalysts (Evonik P25, Evonik P90, Hombikat UV100, Hombikat N100) was evaluated for degradation and removal of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide under solar simulator irradiation. The calcined samples were prepared by heating commercial TiO2 photocatalysts at 573 or 773 K for 4 hours. It was confirmed that before calcination treatment, the P25 TiO2 showed similar activity to the P90 TiO2, which activity was higher than those of Hombikat UV100 and N100 TiO2. The activity of P25 and P90 was reduced when the photocatalysts were calcined at 573 K and 773 K. On the other hand, the Hombikat catalysts showed an improved activity with the increase of calcination temperatures.

Three-dimensional sea urchin-like TiO2 synthesized via facile hydrothermal method: Its properties and solar photocatalytic activity

Three-dimensional (3D) sea urchin-like TiO2 (SUT) superstructures were fabricated via one-pot ethylene glycol (EG)-assisted hydrothermal treatment at 180°C for 12h. As revealed by the scanning electron microscopic images at various hydrothermal reaction time, EG served as a template in the formation of SUT under hydrothermal conditions. EG is a relatively green solvent, has high boiling point, high water solubility, low toxicity, and low cost. At 350°C calcination in air, SUT with high specific surface area (∼197m2/g), pure anatase TiO2 crystallite phase, and high photocatalytic efficiency under natural sunlight was obtained. The solar photocatalytic degradation of 20mgL−1 methylene blue (MB) aqueous solution showed that the performance of as-synthesized SUT-350 was comparable with the commercially available Degussa (Evonik) P25 and Wako anatase TiO2. Mineralization of MB after the treatment was confirmed by the reduction in chemical oxygen demand (COD). Moreover, it was found that micro-sized SUT settled faster than the nano-sized powders of Degussa (Evonik) P25 and Wako anatase TiO2, which means that the as-synthesized SUT is easier to be separated from the liquid phase after the treatment. With these results, SUT synthesized via EG-assisted hydrothermal method, exhibited great potential for eco-friendly and energy-efficient photocatalytic water treatment.

Differences in the vapour phase photocatalytic degradation of ammonia and ethanol in the presence of water as a function of TiO2 characteristics and the presence of O2

Differences in the gas-phase photocatalytic degradation of NH3 and ethanol in the presence of water over two commercial TiO2 materials with different structural characteristics (Evonik's P25 (P25) and Sigma Aldrich's anatase (SA)) were established here using FTIR. The materials were characterized using different techniques including BET, XRD, UV–vis DRS and XPS. The interaction of CO probe molecule with the oxides was evaluated via calorimetry and by in-situ DRIFTS coupled to on-line mass spectrometry. This allowed us to determine differences in the surface properties of the two TiO2 materials. NOx− surface species became evident during the photodegradation of adsorbed NH3 over both SA and P25. However, while surface bidentate nitrate species remained strongly bound to P25, the surface species were fully eliminated from SA. Differences in the photocatalytic degradation of ethanol over P25 and SA were also determined. Ethanol adsorption and its evolution were largely independent of the presence of oxygen for SA, but oxygen affected these processes for P25.

Photocatalytic Hydrogen Formation from Ammonia in an Aqueous Solution Over Pt-Enriched TiO2-ZrO2 Photocatalyst.

The aim of this study was to remove ammonia from an aqueous solution by its decomposition to valuable products such as H2 and harmless N2 under UV light. The decomposition of ammonia by photocatalytic process represents an emerging and interesting way of its removal since beside the need of its reduction from the drinking and wastewaters with the respect to its negative impact on human and mammals health, it can lead to generation of hydrogen as an alternative fuel. A laboratory-synthesized Pt/TiO2-ZrO2 photocatalyst was studied and its photocatalytic activity was compared with the activity of commercial TiO2 Evonik P25. The Pt/TiO2-ZrO2 photocatalyst was prepared by combining a sol-gel process controlled within reverse micelles of nonionic surfactant Triton X-114 in cyclohexane, impregnation under vacuum and calcination. Explored photocatalysts were characterized by organic elementary analysis, nitrogen physisorption, XRD, FESEM and UV-Vis spectroscopy. The real platinum content in the Pt/TiO2-ZrO2 photocatalyst was determined by ICP-MS. The photocatalytic decomposition of ammonia was investigated in the time range of 0-12 h. During the first two hours the generation of hydrogen was almost negligible. The generation of hydrogen increased after 4 h of irradiation. Based on time dependences of ammonia decomposition the kinetic rate constants for Pt/TiO2-ZrO2 and TiO2 Evonik P25 photocatalysts were calculated. The ammonia photocatalytic decomposition was described well by the first order kinetic equation. The photocatalytic ammonia decomposition over the platinized TiO2-ZrO2 photocatalyst was proving 2 times higher photocatalytic performance than Evonik P25 (1241 μmol/g(cat) and 665 μmol/g(cat), respectively).