The catalytic properties of samples containing Pd and Co metals on carbon supports (IR-pyrolyzed chitosan (CT) with an activated surface and detonation nanodiamonds (DNDs) have been studied in the ethanol steam reforming process. CT is a promising catalyst support due to its developed surface and the presence of nitrogen-containing groups capable of sorbing water molecules. The use of a membrane reactor with a Pd–Ru–In membrane has significantly increased the efficiency of the ethanol steam reforming process due to removing hydrogen from the reaction zone. The hydrogen yield in the membrane reactor increases twofold or more compared to a conventional reactor, while the proportion of reaction byproducts (CO and acetaldehyde) decreases. The highest hydrogen yield (15.8 mol/h per gram of catalyst) in the membrane reactor is achieved using a Pd–Co/CTKOH catalyst.

We have studied Cu–Zn and Cu–Ni containing catalysts on carbon supports based on IR-pyrolyzed chitosan and detonation nanodiamond (DND) and assessed their activity for the methanol steam reforming process. All of the catalysts have demonstrated rather high activity for this process and good stability over 30 h of continuous operation. The DND-based catalysts have been shown to have better performance, which seems to be due to their larger surface area and the nature of the functional groups on their surface. The activity of the bimetallic catalysts and the nature of the supports have been shown to be interrelated.

Изучены катализаторы на углеродных носителях на основе ИК-пиролизованного хитозана и детонационных наноалмазов (ДНА), содержащие Cu и Zn или Ni, в процессе паровой конверсии метанола. Все исследованные образцы показали достаточно высокую активность в данном процессе и стабильность в течение 30 ч непрерывной работы. Показано преимущество катализаторов на основе ДНА, причиной чего, видимо, является их более развитая поверхность и природа присутствующих на ней функциональных групп. Показана взаимосвязь между активностью биметаллических катализаторов и природой носителя.

We have studied the catalytic activity of LiZr2(PO4)3-based NASICON-type phosphates for conversion of C2 and C3 aliphatic alcohols with the aim of selectively preparing C2–C4 olefins. Selectivity has been controlled via partial heterovalent substitutions of In3+ or Nb5+ for Zr4+ or Mo for phosphorus. We have investigated the structure and morphology of the synthesized catalysts. The nature of the dopants has been shown to play a key role in determining the selectivity of the catalysts studied. Partial In3+ substitution for Zr4+ improves the dehydrogenating properties of the materials, whereas partial substitutions of Nb5+ for Zr4+ and Mo6+ for P5+ improve their dehydrating properties. We have demonstrated the possibility of highly selective preparation of ethylene and butylenes from ethanol and of propylene from propanol-1 and propanol-2.

A study of methanol steam reforming (MSR) in the presence of a Ni0.2–Cu0.8/Ce0.3Zr0.7O2-δ catalyst in conventional and membrane reactors has revealed that the hydrogen yield in a reactor with a Pd–Cu membrane is higher than that in a conventional flow reactor. It has been shown that the Pd–Cu alloy membrane exhibits high hydrogen permeability. Methanol steam reforming in the membrane reactor provides the production of high-purity hydrogen, because a stream of pure hydrogen free from any impurities is effluent from the permeate zone. Measurements of the hydrogen permeability of the Pd–Cu alloy foil membrane in the membrane reactor before and after catalysis have been conducted.

The possibility of paraffins and C4 olefins mixture separation on membranes made of polyethylene with radiation-grafted sulfonated polystyrene is shown. The selective separation is achieved due to the butenes and isobutene facilitated transfer in the form of a π-complex with a proton. Moreover, despite the significantly larger cross-sectional size, obstructing the transfer, isobutene molecules are also transferred much faster than butane, and the separation coefficient reaches 3.8. An unusual fact was discovered of separation selectivity and permeability increase with the separated gases flow humidity rise.

Ethanol steam reforming (ESR) in the presence of bimetallic nanocatalysts containing Pd–Ru, Pd–Ni, Pt–Ru, and Pt–Ni alloys deposited on detonation nanodiamonds (DNDs) in conventional and membrane reactors has been studied. The effect of some ESR parameters, such as catalyst composition, water/ethanol molar ratio, and temperature, on the hydrogen yield has been studied. The highest hydrogen yield is achieved in a conventional reactor using a Pt–Ru/DND catalyst. In the case of the ESR process running in a membrane reactor and simultaneous removal of hydrogen through membranes made of Pd–Ru or Pd–Ru–In alloys, the hydrogen yield is higher than that obtained in ESR in a conventional reactor. The hydrogen recovery rate from the retentate zone is up to 46%, whereas a high-purity hydrogen stream is withdrawn from the permeate zone.

We have studied the catalytic activity of Cu–Ni bimetallic catalysts on yttrium-, tin-, zinc-, and niobium-doped zirconia and ceria supports for methanol steam reforming (MSR), a process for hydrogen production, and examined the effect of the nature of the dopants and annealing temperature on the structure and particle size of the oxide supports and the catalytic activity of the metal oxide composites. In all cases, the addition of heterovalent ions improved the catalytic activity of the materials for the MSR process in comparison with undoped zirconia. The highest hydrogen yield was reached in the case of catalysts doped with niobium and yttrium oxides.

We have carried out a comparative study of the catalytic activity of nanostructured M–Ru (M = Pt, Pd, Rh) bimetallic catalysts supported on detonation nanodiamond (DND) for methanol steam reforming (MSR) and ethanol steam reforming (ESR) processes in a conventional and a membrane reactor. The catalysts have been characterized by X-ray diffraction, transmission electron microscopy, and BET measurements. In the ESR process, the highest hydrogen yield is ensured by the Pt–Ru/DND catalyst, whereas the Ru–Rh/DND catalyst exhibits the highest activity for the MSR reaction. Our results demonstrate that, if the processes in question are run in a membrane reactor with a Pd–Ru membrane, there is a stable hydrogen flow, free of CO and other impurities, in the permeate zone even at temperatures on the order of 400°C.

Results of hydrogen production study in methanol steam reforming (MSR) process with the use of Ru0.5–Rh0.5 catalysts supported on different carbon materials: synthetic graphite-like material Sibunit, carbon black Ketjenblack EC600DJ, detonation nanodiamonds (DND) and ZrO2-based material with fluorite structure, doped with ceria, have been described. The samples have been tested in conventional flow reactor and membrane (MR) reactor, containing Pd-based membranes with different composition, thickness and surface architecture. It has been shown that the catalytic activity of the composites depends on the support nature. The RuRh/DND catalyst exhibits the highest activity, whereas RuRh/Ce0.1Zr0.9O2–δ is the most selective. The use of PdAg (23%) foil with the surface modified by palladium black showed great advantages comparing to the smooth dense membrane. The use of the MR with the PdAg membrane improves the MSR reaction and provides almost 50% increase in the hydrogen yield. The hydrogen produced with the use of the MR is ultra pure.

The possibility of ethane/ethylene mixture separation at the passing these gases through polyethylene-graft-sulfonated polystyrene membranes in silver and hydrogen forms has been shown. The results showed that the permeability of ethylene and the value of the separation coefficient increased significantly with increasing relative humidity of the separated gases. It was concluded that in both cases the transfer of ethylene occured in the form of a positively charged complex. The patterns of change in the permeability and separation factor were explained on the basis of the structure of the initial membranes and the solubility of the separated gases in the "phases" forming the membrane.

The process of oxidative dehydrogenation of ethane (ODE) was carried out in a catalytic membrane reactor-distributor on a Mo-V-Te-Ox catalyst supported on asymmetric ceramic membranes. The obtained results show the obvious advantages of ODE with the use of a membrane system. Application of the membrane approach allows us to use initial gas mixtures with the O2:C2H6 ratios that are unacceptable for safety reasons in conventional reactors. Under optimal process conditions, the conversion of ethane of 70% can be achieved in a membrane reactor while maintaining the ethylene selectivity in the range of 95–98%.

— This paper presents a study of oxidative dehydrogenation of ethane (ODHE) on nanostructured single-component and multicomponent catalysts based on V 5+ , Mo 5+ , and Nb 5+ oxides and produced on alumina by molecular layering. It has been shown that the molybdenum-containing catalysts exhibit higher activity for ODHE in both single-component and binary samples and ensure higher ethylene selectivity. We have demonstrated advantages of ODHE on membrane–catalyst systems in the form of asymmetric ceramic tubes, with catalysts placed inside of them. The membrane–catalyst systems produced by molecular layering offer considerably higher activity and selectivity in ODHE.

Metal oxide-stabilized zirconia supports (MxZr1-xO2-delta) with different dopants (M = Y, La, Ce) were prepared by coprecipitation method. Bimetallic Cu Ni and Ru Rh catalysts supported on MxZr1-xO2-delta were prepared by the sequential wetness impregnation method, for use in hydrogen production by methanol steam reforming. The effect of the nature and quantity of the dopant cation (M = Y, Ce) on the catalytic performance of zirconia supported metal catalysts was investigated. The activity of Ni-Cu/YxZr1-xO2-(x/2) (x = 0.1-0.3) samples increases with an increase in yttrium concentration due to the formation of oxygen vacancies. The dependence of the catalytic activity on the ceria concentration was not monotonous. The sample containing 10% of cerium oxide showed the highest activity. The performance of a Ni-Cu/La0.1Zr0,9O1.95 sample was compared with the performance of a Y and Ce containing samples with the same quantity of dopant cation (10%). The La doped catalyst was more active than the yttria-containing composites, but its selectivity was lower. The catalyst based on Ru-Rh alloy differed with significantly higher activity and lower selectivity compared with Ni-Cu samples. The selectivity of the process was not less than 99.5% for all catalysts even at the high temperatures. At the same time, the improved activity of the catalyst also results in an increase in carbon monoxide formation while the hydrogen selectivity decreases. The optimal characteristics, such as rather high hydrogen yield, good selectivity and stability were shown by the catalyst with Ce0.1Zr0.9O2-delta support. (C) 2017 Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.

In-, Nb-, Mo-doped lithium complex phosphates and HZr2(PO4)(3) with NASICON-type structure were synthesized in this paper. Particle size distribution lies between 50 and 300 nm. The obtained samples were characterized by X-ray diffraction analysis, scanning electron microscopy and X-ray microanalysis. Investigation of the catalytic properties of synthesized compounds in the C1-C2 alcohols conversions showed that heterovalent doping has a determining effect on the obtained catalysts' activity and selectivity. It is shown that the thermodynamic factors and the dopant ability to change the degree of oxidation and acid function of the catalysts play a key role in methanol and ethanol conversion. A number of catalysts show the high activity and selectivity of the formation of dimethyl and diethyl ethers and ethylene. High selectivity for C4 hydrocarbons is achieved by LiZr2(PO4)(3) and Li0.5Zr2P2.5Mo0.5O12 catalysts (64 and 49%, respectively) in the case of ethanol conversion. (C) 2018 Elsevier B.V. All rights reserved.