NiO/Mn3O4整体式催化剂催化分解臭氧的性能

将原料Ni(NO₃)₂·6H₂O、Mn₃O₄粉末和拟薄水铝石用球磨机球磨,以所得的浆料浸渍堇青石,经过焙烧,得到不同比例的NiO/Mn₃O₄催化剂。 通过催化分解臭氧活性测试发现,在空速为20000 h^-1时, 30NiO/Mn₃O₄(NiO占总质量的30%)催化剂的活性最高,臭氧分解率达到98%,催化剂活性稳定。 当提高空速为40000 h^-1,50NiO/Mn₃O₄(NiO占总质量的50%)催化剂的活性最高,臭氧分解率在90%左右,并且出现失活现象。 通过X射线衍射(XRD)、程序升温(TPR)、X射线光电子能谱分析(XPS)、BET比表面积法等表征,发现Mn₃O₄和NiO复合催化剂的比表面积大于单一金属氧化物催化剂的比表面积并且在Mn₃O₄和NiO复合催化剂中Mn₃O₄与NiO发生电子相互作用。 催化剂中的Mn₃O₄与NiO的协同催化作用。 使得Mn₃O₄与NiO混合物催化剂的还原温度降低,分解臭氧(O₃)活性提高。     

Surface Modification of (001) Facets Dominated TiO2 with Ozone for Adsorption and Photocatalytic Degradation of Gaseous Toluene

This study investigated the positive effect of surface modification with ozone on the photocatalytic performance of anatase TiO₂ with dominated (001) facets for toluene degradation. The performance of photocatalyst was tested on a home-made volatile organic compounds degradation system. The ozone modi cation, toluene adsorption and degradation mechanism were established by a combination of various characterization methods, in situ diffuse reflectance infrared fourier transform spectroscopy, and density functional theory calculation. The surface modi cation with ozone can significantly enhance the photocatalytic degradation performance for toluene. The abundant unsaturated coordinated 5c-Ti sites on (001) facets act as the adsorption sites for ozone. The formed Ti-O bonds reacted with H₂O to generate a large amount of isolated Ti_5c-OH which act as the adsorption sites for toluene, and thus significantly increase the adsorption capacity for toluene. The outstanding photocatalytic performance of ozone-modified TiO₂ is due to its high adsorption ability for toluene and the abundant surface hydroxyl groups, which produce very reactive OH radicals under irradiation. Furthermore, the O₂ generated via ozone dissociation could combine with the photogenerated electrons to form superoxide radicals which are also conductive to the toluene degradation.     

Development of spin-coated Si/TiOx/Pt/TiOx electrodes for the electrochemical ozone production

A novel electrode having the compositional sequence Si/TiOx/Pt/TiOx was developed for ozone electrogeneration. The spin-coating method, the sputtering deposition technique, and a post-annealing procedure were all combined to assemble the electrode composition. A two-compartment electrolytic cell separated by a Nafion membrane was used to generate ozone galvanostatically. The X-ray photon electron spectroscopy (XPS) and atomic force microscopy (AFM) were used to reveal the electrode composition and morphology. The influence of several factors including the electrode's annealing temperature, the electrolyte composition, and the electrolysis’ current density on the efficiency of ozone production was investigated. A maximum ozone generation efficiency of 2.5% was obtained at 74 mA cm⁻² at room temperature. Interestingly, the electrode preserved (ca. 80%) of its original activity to produce ozone after 50 h of continues electrolysis at 74 mA cm⁻² at room temperature.     

Efficient and facile one pot carboxylation of multiwalled carbon nanotubes by using oxidation with ozone under mild conditions

In this study, oxidation of carbon nanotubes with ozone in the presence of hydrogen peroxide was investigated. The reaction was performed under clean and mild conditions and oxidized products with high concentration of oxygenated groups were yielded. The reaction products were characterized with attenuated total reflectance (ATR), Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffractometry (XRD), back titration, X-ray photoelectron spectroscopy (XPS) and the dispersion behavior of the oxidized multiwalled carbon nanotubes (MWCNTs) was also studied. The results confirmed the presence of high concentrations of oxidative groups on the carbon nanotubes (CNTs) treated by the method of the present work.     

CW-Cavity Ring Down spectroscopy of O3. Part 1: Experiment and analysis of the 6200-6400 cm spectral region

The absorption spectrum of the ¹⁸O₃ isotopologue of ozone has been recorded in the 6200-6400 cm⁻¹ region by high sensitivity CW-Cavity Ring Down Spectroscopy. The spectrum is dominated by the 2ν₁ + 5ν₃ and 2ν₁ + 3ν₂ + 3ν₃ bands at 6270.6 and 6392.2 cm⁻¹, respectively which were treated independently. The rovibrational analysis of the 2ν₁ + 5ν₃ band has evidenced that the (2 0 5) upper state is perturbed by Coriolis resonance interactions with the (0 1 6), (3 0 4) and (3 5 0) states. A total of 659, 89, 131 and 5 transitions were assigned to the 2ν₁ + 5ν₃, ν₂ + 6ν₃, 3ν₁ + 4ν₃ and 3ν₁ + 5ν₂ bands, respectively. In the case of the 2ν₁ + 3ν₂ + 3ν₃ band, 344 transitions were assigned. Some of them were found perturbed by a Coriolis interaction of the (2 3 3) state with the (5 2 0) state.Overall, 681 energy levels were derived from the analysis of the 2ν₁ + 5ν₃ and 2ν₁ + 3ν₂ + 3ν₃ band systems. In both cases, a suitable effective Hamiltonian was elaborated, allowing accounting satisfactorily for the retrieved rovibrational energy levels. In addition, dipole transition moment parameters were determined by a least-squares fit to the measured line intensities. The effective Hamiltonian and transition moment operator parameters were used to generate a list of 1619 transitions given as Supplementary material.     

CRDS spectroscopy of O3. Part 2: Analysis of six interacting bands between 5930 and 6080 cm

The absorption spectrum of ¹⁸O₃ has been recorded in the 5930-6080 cm⁻¹ region using CW-Cavity Ring Down Spectroscopy. 1888 transitions belonging to five bands have been assigned. Three of them are A-type bands: 2ν₂ + 5ν₃, ν₁ + ν₂ + 5ν₃ and 5ν₁ + ν₃, and two bands are of B-type: 2ν₁ + ν₂ + 4ν₃ and 4ν₁ + 3ν₂. Despite a complex spectral pattern perturbed by many rovibrational resonances, it has been possible to find a suitable effective Hamiltonian model reproducing all the transition wavenumbers (corresponding to 1016 energy levels) with an rms deviation of 9.5 × 10⁻³ cm⁻¹. A set of 721 line intensities was determined and fitted to derive the effective transition moment parameters. This set of parameters and the experimental energy levels were used to generate a complete line list of 2795 transitions allowing to generate synthetic spectrum in good agreement with the experimental spectrum.     

Effect of surface morphology of lead dioxide particles on their ozone generating performance

Lead dioxide is widely applied in anodic oxidation processes like the ozone generation and the degradation of various organic species in aqueous solution. In this paper, the correlation between the morphology of the lead dioxide particles and their ozone generating performance was investigated. The anode prepared by crude lead dioxide particles exhibited better performance in ozone generation than that prepared by milled lead dioxide particles. The reason lies in, probably, the higher stability of O on the surfaces of the crude lead dioxide particles. With 220-h running of the anode prepared with crude lead dioxide particles, the overall diameters of the lead dioxide particle decreased drastically, and many nano-scaled lead dioxide particles presented on the surfaces of the particles, which had resulted from recrystallization of the particles at high potentials. The two facts might be the main reason for the decline of the membrane electrode performance. Furthermore, a small percentage of α-lead dioxide detected in lead dioxide crystal may also decline the performance of the membrane electrode.     

Infrared laser heterodyne ozone spectrum

An infrared laser heterodyne spectrometer (IRLHS) has been developped for both laboratory and atmospheric studies. A long path and temperature adjustable cell has been designed for laboratory spectra. An ozone spectrum with 5MHz (0.00016 cm^–1) resolution is presented.     

CW-Cavity Ring Down Spectroscopy of the ozone molecule in the 5980-6220 cm region

The absorption spectrum of ozone, ¹⁶O₃, has been recorded in the 5980-6220 cm⁻¹ region by high sensitivity CW-Cavity Ring Down Spectroscopy (α_min ∼ 3 × 10⁻¹⁰ cm⁻¹). This study extends a first investigation with the same experimental set-up limited to the 6030-6090 cm⁻¹ spectral region [M.-R. De Backer-Barilly, A. Barbe, Vl.G. Tyuterev, D. Romanini, B. Moeskops, A. Campargue, J. Mol. Struct. 780-781 (2006) 225-233] where the analysis of two A-type bands was reported, using FTS spectra for complementary information. The spectral extension of the recordings allows not only to enlarge considerably the observed transitions of these two bands, but more importantly, to assign four new bands: the 3ν₂ + 4ν₃,5ν₁ + ν₂ and ν₁ + 2ν₂ + 4ν₃ B-type bands which were considered as dark in our previous report and the 3ν₁ + 3ν₂ + ν₃ A-type band. The high mixing of the observed states approaching the dissociation limit, leads to the breakdown of the polyad structure and ambiguities in the vibrational labelling which are discussed. Finally, 1789 transitions were assigned, and a suitable Hamiltonian model allows reproducing correctly the observations for five of the six observed bands. The list of 1004 experimentally determined energy levels is provided. The determined effective Hamiltonian and transition moment operators were used to generate a list of 5338 transitions given as Supplementary Material. It is interesting to note that the d₅ parameter of the effective transition moment is of great importance to account for the observed intensities of the B-type bands.     

CW-cavity ring down spectroscopy of the ozone molecule in the 6220-6400 cm region

The absorption spectrum of ozone,¹⁶O₃, has been recorded in the 6220-6400 cm⁻¹ region by high sensitivity CW-cavity ring down spectroscopy (α_min ∼ 3 × 10⁻¹⁰ cm⁻¹). 1836 rovibrational transitions have been assigned to the 2ν₂ + 5ν₃, 5ν₁ + ν₃ and 2ν₁ +  2ν₂ + 3ν₃ A-type bands centred at 6305, 6355 and 6387 cm⁻¹, respectively. In addition, 99 lines of the very weak ν₁ + 2ν₂ +  4ν₃ and 4ν₁ + 3ν₂ B-type bands are identified. The modeling of the observed spectrum in the effective Hamiltonian approach was particularly laborious and complex as several rovibrational interactions of both Coriolis and anaharmonic type were found to be of importance, in particular for the (124) vibrational state. Nevertheless, it has finally been possible to fit the 990 experimentally determined energy levels with an rms deviation of 8.29 × 10⁻³ cm⁻¹ and to derive the transition moment parameters allowing a satisfactory reproduction of the observed intensities. As the differences in positions between the final calculations and observations are still larger than the experimental accuracy, we provide the list of all energy levels derived from the observation, in addition to their differences with the calculated ones. These experimental energy levels, with the transition moment parameters were used to generate a line-list of 2451 transitions, reproducing the observed spectrum. This list is given as Supplementary Material.