Study of the structure of semi-coke using EPR and NMR spectroscopy methods

The work carried out comprehensive studies of a number of industrial semi-cokes using EPR and NMR methods. Apply of EPR spectroscopy, it was shown that in all the studied semi-cokes there are two types of radical structures, the first of which are low-molecular aromatic radicals.The second type is conjugated polyaromatic structures, in which the unpaired electron is delocalized. Line shape analyzing in EPR spectra, it was found that there are differences in the presented line of isotropic cokes. In this work was shown that EPR is a highly sensitive method that makes it possible to monitor changes in the molecular structure during the production of semi-cokes. The results of the EPR studies obtained in this work are in good agreement with the results of NMR spectroscopy. The results obtained show that changing the composition of the feedstock and technological operations to obtain high-quality anisotropic cokes is impossible without assessing the molecular structure of the intermediate coking products

Selective Hydrogenation of 2-Methyl-3-butyn-2-ol in Microcapillary Reactor on Supported Intermetallic PdZn Catalyst, Effect of Support Doping on Stability and Kinetic Parameters

The development of active, selective, and stable multicrystalline catalytic coatings on the inner surface of microcapillary reactors addresses environmental problems of fine organic synthesis, in particular by reducing the large quantities of reagents and byproducts. Thin-film nanosized bimetallic catalysts based on mesoporous pure titania and doped with zirconia, ceria, and zinc oxide, for use in microreactors, were developed, and the regularities of their formation were studied. The efficiency of PdZn/TixM1−xO2±y (M = Ce, Zr, Zn) in the hydrogenation of 2-methyl-3-butyn 2-ol was studied with an emphasis on the stability of the catalyst during the reaction. The catalytic parameters depend on the adsorption properties and activity of PdZn and Pd(0) active centers. Under reaction conditions, resistance to the decomposition of PdZn is a factor that affects the stability of the catalyst. The zinc-doped coating proved to be the most selective and stable in the reaction of selective hydrogenation of acetylenic alcohols in a microcapillary reactor. This coating retained a high selectivity of 98.2% during long-term testing up to 168 h. Modification of the morphology and electronic structure of the active component, by doping titania with Ce and Zr, is accompanied by a decrease in stability

Hydrogen Production through Autothermal Reforming of Ethanol: Enhancement of Ni Catalyst Performance via Promotion

Autothermal reforming of bioethanol (ATR of C2H5OH) over promoted Ni/Ce0.8La0.2O1.9 catalysts was studied to develop carbon-neutral technologies for hydrogen production. The regulation of the functional properties of the catalysts was attained by adjusting their nanostructure and reducibility by introducing various types and content of M promoters (M = Pt, Pd, Rh, Re; molar ratio M/Ni = 0.003–0.012). The composition–characteristics–activity correlation was determined using catalyst testing in ATR of C2H5OH, thermal analysis, N2 adsorption, X-ray diffraction, transmission electron microscopy, and EDX analysis. It was shown that the type and content of the promoter, as well as the preparation mode (combined or sequential impregnation methods), determine the redox properties of catalysts and influence the textural and structural characteristics of the samples. The reducibility of catalysts improves in the following sequence of promoters: Re < Rh < Pd < Pt, with an increase in their content, and when using the co-impregnation method. It was found that in ATR of C2H5OH over bimetallic Ni-M/Ce0.8La0.2O1.9 catalysts at 600 °C, the hydrogen yield increased in the following row of promoters: Pt < Rh < Pd < Re at 100% conversion of ethanol. The introduction of M leads to the formation of a NiM alloy under reaction conditions and affects the resistance of the catalyst to oxidation, sintering, and coking. It was found that for enhancing Ni catalyst performance in H2 production through ATR of C2H5OH, the most effective promotion is with Re: at 600 °C over the optimum 10Ni-0.4Re/Ce0.8La0.2O1.9 catalyst the highest hydrogen yield 65% was observed

Combined Steam and CO₂ Reforming of Methane over Ni-Based CeO₂-MgO Catalysts: Impacts of Preparation Mode and Pd Addition

The sol–gel template technique makes it possible to synthesize a stable and efficient nickel catalyst based on magnesium-modified cerium oxide Ce0.5Mg0.5O1.5 for the combined steam and CO2 reforming of methane. To stabilize dispersed forms of the active component in the matrix of the support, the catalysts were synthesized by changing the support precursor (cerium acetate and chloride), the active component composition (Ni, NiPd) and the method of introducing nanoparticles. The relationship was established between the physicochemical and catalytic characteristics of the samples. The use of cerium acetate as a support precursor provided smaller pore and crystallite sizes of the support, a stabilization of the dispersed forms of the active component, and excellent catalytic characteristics. The introduction of Pd into the Ni nanoparticles (Pd/Ni = 0.03) increased the resistance of the active component to sintering during the reaction, ensuring stable operation for 25 h of operation. The increased stability was due to a higher concentration of defective oxygen, a higher dispersion of bimetallic NiPd nanoparticles, and the Ni clusters strongly interacting with the NiO-MgO solid solution. An efficient and stable Ni0.194Pd0.006Ce0.4Mg0.4O1.4 catalyst for the conversion of CO2 into important chemicals was developed. With the optimal composition and synthesis conditions of the catalyst, the yield of the target products was more than 75%

Spectral Study of Modified Humic Acids from Lignite

The IR-Fourier, ESR and solid-state 13C NMR analysis are used for investigation of unmodified and modified humic acids obtained from Tisul lignite (the Kansko-Achinsk Basin). Treatment with Hydrogen peroxide used for modification of humic acids and it changes the functionalgroup composition of the humic acids and increases the sorptional capacit

Hydrogen Production through Bi-Reforming of Methane: Improving Ni Catalyst Performance via an Exsolution Approach

Hydrogen production through the bi-reforming of methane over exsolution-derived Ni catalysts has been studied. Nickel-based catalysts were prepared through the activation of (CeM)1−xNixOy (M = Al, La, Mg) solid solutions in a reducing gaseous medium. Their performance and resistance to coking under the reaction conditions were controlled by regulating their textural, structural, morphological, and redox properties through adjustments to the composition of the oxide matrix (M/Ce = 0–4; x = 0.2–0.8; y = 1.0–2.0). The role of the M-dopant type in the genesis and properties of the catalysts was established. The efficiency of the catalysts in the bi-reforming of methane increased in the following series of M: M-free 1−xNixOy catalysts. At 800 °C the optimum Ce0.6Mg0.2Ni0.2O1.6 catalyst provided a stable H2 yield of 90% at a high level of CO2 and CH4 conversions (>85%)

Ventilation-Associated Particulate Matter Is a Potential Reservoir of Multidrug-Resistant Organisms in Health Facilities

Most healthcare-associated infections (HCAIs) develop due to the colonisation of patients and healthcare workers by multidrug-resistant organisms (MDRO). Here, we investigated whether the particulate matter from the ventilation systems (Vent-PM) of health facilities can harbour MDRO and other microbes, thereby acting as a potential reservoir of HCAIs. Dust samples collected in the ventilation grilles and adjacent air ducts underwent a detailed analysis of physicochemical properties and biodiversity. All Vent-PM samples included ultrafine PM capable of reaching the alveoli. Strikingly, >70% of Vent-PM samples were contaminated, mostly by viruses (>15%) or multidrug-resistant and biofilm-producing bacterial strains (60% and 48% of all bacteria-contaminated specimens, respectively). Total viable count at 1 m from the ventilation grilles was significantly increased after opening doors and windows, indicating an association between air flow and bacterial contamination. Both chemical and microbial compositions of Vent-PM considerably differed across surgical vs. non-surgical and intensive vs. elective care units and between health facilities located in coal and chemical districts. Reduced diversity among MDRO and increased prevalence ratio in multidrug-resistant to the total Enterococcus spp. in Vent-PM testified to the evolving antibiotic resistance. In conclusion, we suggest Vent-PM as a previously underestimated reservoir of HCAI-causing pathogens in the hospital environment

Hydrogen Production through Bi-Reforming of Methane: Improving Ni Catalyst Performance via an Exsolution Approach

Hydrogen production through the bi-reforming of methane over exsolution-derived Ni catalysts has been studied. Nickel-based catalysts were prepared through the activation of (CeM)1−xNixOy (M = Al, La, Mg) solid solutions in a reducing gaseous medium. Their performance and resistance to coking under the reaction conditions were controlled by regulating their textural, structural, morphological, and redox properties through adjustments to the composition of the oxide matrix (M/Ce = 0–4; x = 0.2–0.8; y = 1.0–2.0). The role of the M-dopant type in the genesis and properties of the catalysts was established. The efficiency of the catalysts in the bi-reforming of methane increased in the following series of M: M-free < La < Al < Mg, correlating with the structural behavior of the nickel active component and the anti-coking properties of the support matrix. The preferred M-type and M/Ce ratio determined the best performance of (CeM)1−xNixOy catalysts. At 800 °C the optimum Ce0.6Mg0.2Ni0.2O1.6 catalyst provided a stable H2 yield of 90% at a high level of CO2 and CH4 conversions (>85%)

Nanoscale control during synthesis of Me/La2O3, Me/CexGd1-xOy and Me/CexZr 1-xOy (Me = Ni, Pt, Pd, Rh) catalysts for autothermal reforming of methane

Supported catalysts Me/La2O3, Me/CexGd1−xOy and Me/CexZr1−xOy (Me = Ni, Pt, Pd, Rh) were developed for the autothermal reforming of methane (ATR of CH4). The influence of support composition (La2O3, CexGd1−xOy, x = 0.50–0.90 and CexZr1−xOy, x = 0.33–0.67), type and content of the active component (5–30 wt% Ni; 0.5–1.5 wt% Pt, Pd or Rh) on the nanostructure of catalysts and their performance in the ATR of CH4 was investigated. The properties and structure of the catalysts in the course of their preparation and operation in the reaction were systematically characterized by means of X-ray diffraction, BET N2 adsorption/desorption, H2 temperature-programmed reduction, transmission electron microscopy and X-ray photoelectron spectroscopy techniques. The state and particle size of Ni-containing species were regulated by the support composition and Ni content. In case of the La2O3 support, the strong interaction between NiO and La2O3 led to the formation of two binary oxides LaNiO3 and La2NiO4 in the fresh samples, the composition of which was regulated by the Ni content. In case of the CexGd1−xOy and CexZr1−xOy supports, in contrast to the La2O3 support, nickel oxide and ceria-based solid solution were formed in the fresh samples. The catalyst evolution under reaction condition was studied. The conversion of methane and product (H2, CO) yields considerably increased when Ce0.8Gd0.2Oy or Ce0.5Zr0.5Oy instead of La2O3 were used as catalyst supports: at 850 °C the yields of ∼35% H2 and ∼41% CO at CH4 conversion ∼76% were observed for the 10 wt%Ni/La2O3, while the yields of ∼49% H2 and ∼66% CO at CH4 conversion ∼97% were observed for the 10 wt% Ni/Ce0.5Zr0.5O2, which correlates with the increase of reducibility of Ni species as a result of weakening of the Ni–support interaction. The optimal value of metal content for the catalyst performance also depends on the support composition. The best ATR of CH4 performance is provided by 10 wt% Ni/Ce0.5Zr0.5O2 and 1 wt% Rh/Ce0.8Gd0.2O2 catalysts.The presented research has received funding from the European Union 7th Framework Programme (FP7/2007–2013) under grant agreement No. 262840.Peer Reviewe