High-strength activated carbon produced by pyrolysis of a furfural copolymer was used as a support in a palladium catalyst for hydrodechlorination (HDC) of diclofenac in water in the presence of hydrogen. Diclofenac was removed from water by HDC and adsorption, the contribution of which was dominant due to a high specific surface area of the microporous support, whereas HDC played a role to convert residual amounts of chlorinated organics into safer products. The prereduction conditions strongly affected the catalyst performance: reduction in aqueous solutions at 30 degrees C produced more efficient catalysts than those obtained by dry reduction at 30 and 300 degrees C.

The performance of Pd catalysts supported on ordered (ZrSBA) or disordered (ZS) ZrO2-modified SiO2 was evaluated in the hydrodechlorination of ecotoxic diclofenac with H2 in an aqueous medium at 30 degrees C, after pre-reduction of the catalysts with H2 at 320 degrees C or in water at 30 degrees C. The ordered 0.1 wt% Pd/ZrSBA catalysts with lower Pd content, reduced at both temperatures, showed similar diclofenac conversion rates that were comparable to or much higher than those of the 0.86 wt% Pd/ZS catalysts reduced at 320 or 30 degrees C, respectively. A comprehensive analysis using XRD, N2 adsorption, TEM-EDA, TPR and XPS techniques revealed the presence of larger Pd nanoparticles, a reduced degree of Pd decoration with silica and slightly improved reducibility of Pd/ZrSBA at 30 degrees C compared to Pd/ZS, which resulted in a superior efficiency of the former catalyst. Pd Pd Pd/ZrSBA Ordered pores Diclofenac hydrodechlorination TOF/h-1 200 100 0 30 320 T of catalyst reduction with H2/degrees C ZS = ZrO2-SiO2 Pd/ZS Disordered pores

Iron oxide-modified 1Pd0.5Fe and 1Pd10Fe catalysts with a target content of 1 wt

Pd/ZrO2 and Pd/ZrO2SiO2 catalysts prepared by wet impregnation and reduced with H2 under mild (30 °C, aqueous suspension) or harsh (320 °C) conditions were compared in the hydrodechlorination of the microecotoxicant diclofenac in aqueous solution at 30 оС. According to TPR and XPS data, the addition of SiO2 to the support reduces the degree of metal-support interaction and facilitates the reduction of palladium. Despite the lower Pd0 fraction, the Pd/ZrO2 catalyst was more active in the batch reactor: after reduction at 320 °С, it slightly, and after mild reduction, signi cantly (7 times) exceeded Pd/ZrO2SiO2 in catalytic activity. XRD and TEM showed a wider size distribution of palladium nanoparticles in the Pd/ZrO2 sample, while low-temperature N2 adsorption, XPS, and TPR demonstrated better accessi-bility of palladium on the Pd/ZrO2 surface due to reduced decoration with support components and increased pore size. These features explain the increased activity of Pd/ZrO2. Testing in the ow system demonstrated higher DCF conversion in the presence of catalysts reduced at 320°C and higher stability of Pd/ZrO2SiO2 compared to Pd/ZrO2. The stability is ensured by the increased reducibility of Pd2+ with H2 and by the developed surface of Pd/ZrO2SiO2, which prevents deactivation under the action of HCl released in hydrodechlorination.

The effect that introduction of cerium oxide into oxide systems based on chromium and silicon exerts on the catalytic properties of these systems in nonoxidative propane dehydrogenation in a flow-through system with a fixed catalyst bed was studied. The characteristics of the catalysts CrOx–SiO2 and CrOx–CeO2–SiO2, both containing 9 wt

Biohybrid devices based on natural pigment-protein com-plexes are of great interest. Many new reports appear in print each year with new insights into the interactions between proteins and electrodes. In this review, we consider the latest results in the field of designing electrodes based on photo -system I. This review highlights the benefits of nanostructured electrodes, recombinant photosystems, and electrophoretic deposition techniques for uniform photosystem I orientation on an electrode. The focus is on 3D architecturally designed carbon and indium tin oxide electrodes, genetically engineered PSI in biohybrid electrodes, and participation of the reaction center of photosystem I in photocurrent generation.

Monometallic palladium and bimetallic palladium-iron catalysts (1 wt% Pd, 10 wt% Fe) were prepared by sequential (denoted as "-s") and co-(denoted as "-c") impregnation of alumina and silica - zirconia (ZS) supports with metal nitrates. After reduction with H2 at 320 and 30 & DEG;C the catalysts were tested in hydrodechlorination of diclofenac in water at 30 & DEG;C in batch and flow-type reactors. The alumina-supported catalysts were more active than the ZS-supported ones, while the bimetallic catalysts were more efficient than the monometallic Pd ones. The co-impregnated bimetallic catalysts showed higher efficiencies than the catalysts prepared by the sequential deposition of metals. Pd/Al2O3 and PdFe/Al2O3-c provided the same rate of DCF conversion in the batch reactor after both types of preliminary reduction, opening the way for energy saving. The catalysts were studied by XRD, TEM, SEM-EDX, low-temperature N2 physisorption, Mo & BULL;ssbauer spectroscopy, DRIFT-CO and by XPS after in situ reduction at 320 & DEG;C and ex-situ reduction at 30 & DEG;C. The improvements in catalyst efficiency resulted from wider pores, formation of PdFe alloys or Pd-Fe-Ox species on the surface, high Pd0/Pd2} ratio, low extent of Pd encapsulation with the support and especially its coordinately unsaturated sites. The encapsulation degree was the lowest in the co-impregnated catalysts.

Catalysts of the general composition CrOx–ZrO2–SiO2 were prepared by two procedures: (1) one-step precipitation of all the components and (2) introduction of CrOx by impregnation of the ZrO2–SiO2 support. The CrOx content was varied from 4 to 9 wt

A comparison is made of CrO x –ZrO 2 –SiO 2 catalysts (9 wt % chromium oxide based on Cr 2 O 3 ); (Cr + Zr)/Si molar ratio of 0.8) synthesized using different orders of introducing components: (i) the simultaneous precipitation of all components, (ii) the deposition of CrO x on ZrO 2 –SiO 2 via impregnation, and (iii) the co-precipitation of CrO x and ZrO 2 on SiO 2 . The SiO 2 precursors are TEOS in methods (i) and (ii), and SiO 2 produced by calcination of rice husk in (iii). The catalysts are tested in the nonoxidative dehydrogenation of propane in a flow system with a fixed catalyst bed at 500–600°С. The co-precipitation of CrO x and ZrO 2 ensures high efficiency of the catalysts. At 500 and 550°C, the most efficient catalyst is CrZr/SiO 2 synthesized by depositing CrO x and ZrO 2 on SiO 2 ; at 600°C, the best on-stream behavior is exhibited by CrZrSi catalyst synthesized via the simultaneous precipitation of all components. SEM/EDX, XRD, H 2 -TPR, and Raman spectroscopy are used to show that in the catalysts synthesized via the co-precipitation of CrO x and ZrO 2 , these components (which form active sites) are uniformly distributed, have close contact, and are adequately dispersed, while Cr 6+ is readily reduced to Cr 3+ by the hydrogen contained in the reaction medium.

Biohybrid devices based on natural pigment–protein complexes are of great interest. Many new reports appear in print each year with new insights into the interactions between proteins and electrodes. In this review, we consider the latest results in the field of designing electrodes based on photosystem I. This review highlights the benefits of nanostructured electrodes, recombinant photosystems, and electrophoretic deposition techniques for uniform photosystem I orientation on an electrode. The focus is on 3D architecturally designed carbon and indium tin oxide electrodes, genetically engineered PSI in biohybrid electrodes, and participation of the reaction center of photosystem I in photocurrent generation.

Lomonosov Moscow State University and Mendeleev University of Chemical Technology of Russia are the leading high education and research centres in the field of chemistry. Research in computational green chemistry is highly active in both institutions. The ongoing research in the Chemistry Department of Lomonosov Moscow State University covers various topics that involve combined experimental and computational studies related to green chemistry. The theoretical studies focus mainly on chemical reactions using various types of catalysts (including heterogeneous ones, nanoparticles and clusters, and industrial enzymes), photochemical processes related to the conversion of the sun energy using solar cells, and the design of novel organic compounds aiming at extracting radioactive isotopes from liquid wastes. All these studies are supported and complemented by experimental work. Mendeleev University is searching for multi-scale green-chemistry oriented bonding descriptors and applies them to the control of chemical reactions through variation of the properties of the reaction medium—an important line of development of technologies of green organic synthesis. This chapter offers an overview of the interrelated computational and green chemistry studies, highlighting their interactions and mutual benefits.

In this work mesoporous CeO2-SiO2 catalysts with the Ce:Si molar ratios of 1:1 and 4:1 were synthesized by template method and modified with copper to elucidate the role of copper-ceria and ceria-silica interactions in the catalyst efficiency in CO-PROX. The catalysts were characterized by SEM-EDS, AAS, XRD, TPR-H2, TEM, and spectroscopic methods (Raman, EPR and in situ DRIFT of adsorbed CO). The binary catalyst with the equimolar Ce:Si ratio demonstrated better catalytic performance in CO-PROX due to its favorable textural properties and strong ability to anion vacancy formation as confirmed by N2 physisorption and Raman spectroscopy. CuOx/ CeSiOy (Ce:Si = 4:1) demonstrated better low-temperature activity, CO2 selectivity and stability than CuOx/ CeSiOy (Ce:Si = 1:1) and both binary systems because of its unique structure, comprising fine CeO2 particles with a narrow size distribution of 2-3 nm well dispersed on a large surface area, high concentration of the most active in CO oxidation Cu+ sites, formed on CuOx-CeO2 interfaces, and improved ability to surface reoxidation after reduction with the reagents resulted in the decreased Ce3+ concentration. It was also stable in the presence of CO2 and H2O in the reaction mixture. These properties would be difficult to achieve via template preparation methods without SiO2 addition.

Copper was incorporated into the Ce-Sn and comparative Ce-Zr oxide supports by one-pot precipitation in the presence of CTAB template and by the impregnation of templated Ce-Sn and Ce-Zr oxides. The synthesized Cu-Ce-Sn and Cu-Ce-Zr catalysts were tested in the continuous-flow preferential oxidation of CO in hydrogen excess. The one-pot synthesized tin- and zirconium-doped catalysts demonstrated better CO conversion and CO2 selectivity than their impregnated counterparts. For the tin-modified ternary system that showed the best catalytic performance, the copper content was further optimized. The structure, reducibility, surface chemical state and textural properties of the catalysts were analyzed by SEM-EDX, XRD, H2-TPR, Raman spectroscopy, XPS and TEM. The nonmonotonic changes in the specific surface area, Cu+/Cu2+ ratio and ratio of lattice and non-lattice oxygen with increasing the Cu content are discussed in terms of copper distribution in the catalysts. The influence of the interaction between copper oxide species and the cerium–tin/cerium–zirconium oxide support on the performance of the ternary catalysts was thoroughly analyzed and discussed.

The reduction of monometallic Pd/Al2O3 and bimetallic PdFe/Al2O3 catalysts produced by co-impregnation or sequential impregnation of the support with metal salts was possible not only under high temperature hydrogen treatment but also at 30 & DEG;C under the action of aqueous phenol solution and hydrogen. According to the XPS data, both reduction routes provided sufficient degrees of Pd reduction required for fast hydrodehalogenation of 4-chlorophenol and 4-bromophenol to phenol in aqueous solutions. The degree of Pd reduction was higher in the co-impregnated bimetallic PdFe catalyst, which was more efficient in transformation of 4-bromophenol; the bimetallic catalysts were more stable than the monometallic Pd one in the conversion of 4-chlorophenol.

A series of CrOx-ZrO2-SiO2 (CrZrSi) catalysts was prepared by a “one-pot” template-assisted evaporation-induced self-assembly process. The chromium content varied from 4 to 9 wt.% assuming Cr2O3 stoichiometry. The catalysts were characterized by XRD, SEM-EDX, temperature-programmed reduction (TPR-H2), Raman spectroscopy, and X-ray photoelectron spectroscopy. The catalysts were tested in non-oxidative propane dehydrogenation at 500–600 °C. The evolution of active sites under the reaction conditions was investigated by reductive treatment of the catalysts with H2. The catalyst with the lowest Cr loading initially contained amorphous Cr3+ and dispersed Cr6+ species. The latter reduced under reaction conditions forming Cr3+ oxide species with low activity in propane dehydrogenation. The catalysts with higher Cr loadings initially contained highly dispersed Cr3+ species stable under the reaction conditions and responsible for high catalyst activity. Silica acted both as a textural promoter that increased the specific surface area of the catalysts and as a stabilizer that inhibited crystallization of Cr2O3 and ZrO2 and provided the formation of coordinatively unsaturated Zr4+ centers. The optimal combination of Cr3+ species and coordinatively unsaturated Zr4+ centers was achieved in the catalyst with the highest Cr loading. This catalyst showed the highest efficiency.

Abstract The effect of the template nature and modification with MnOx on the catalytic efficiency of Ce0.8Zr0.2O2 (CZ) in oxidation of CO (2 vol% CO and 1 vol% O2 in He, pulse feeding) and soot particles (tight contact between soot and catalyst, TGA/DSC) was analyzed. The CZ catalysts were prepared using the CTAB and sawdust (SD) templates and modified with Mn (8 wt%) by wet impregnation followed by calcination at 400 °С. SEM-EDS, XRD, Raman and photoelectron spectroscopy, N2 adsorption, EPR, TPR-H2 and catalytic tests results demonstrated better catalytic activity of CZ(SD) in CO oxidation than of CZ(CTAB) because of the biomorphic texture, higher structural defectiveness and improved oxygen mobility of the former catalyst. Low surface reducibility and low concentration of active oxygen species on the CZ(SD) surface deteriorated its catalytic efficiency in the topochemical reaction of soot oxidation. Despite the different structure and degree of interaction between MnOx and CZ, the Mn-modified catalysts showed the similar catalytic properties: much better than of both unmodified catalysts in CO oxidation and worse than of CZ(CTAB) in soot oxidation. Mn2+ ions incorporated better into the surface layer of CZ(SD) than of CZ(CTAB), for which the inhomogeneous distribution of MnOx and decreased specific surface area were observed.

A mesoporous support based on silica and zirconia (ZS) was used to prepare monometallic 1 wt% Pd/ZS, 10 wt% Fe/ZS, and bimetallic FePd/ZS catalysts. The catalysts were characterized by TPR-H2, XRD, SEM-EDS, TEM, AAS, and DRIFT spectroscopy of adsorbed CO after H2 reduction in situ and tested in hydrodechlorination of environmental pollutant 4-chlorophelol in aqueous solution at 30 °C. The bimetallic catalyst demonstrated an excellent activity, selectivity to phenol and stability in 10 consecutive runs. FePd/ZS has exceptional reducibility due to the high dispersion of palladium and strong interaction between FeOx and palladium, confirmed by TPR-H2, DRIFT spectroscopy, XRD, and TEM. Its reduction occurs during short-time treatment with hydrogen in an aqueous solution at RT. The Pd/ZS was more resistant to reduction but can be activated by aqueous phenol solution and H2. The study by DRIFT spectroscopy of CO adsorbed on Pd/ZS reduced in harsh (H2, 330 °C), medium (H2, 200 °C) and mild conditions (H2 + aqueous solution of phenol) helped to identify the reasons of the reducing action of phenol solution. It was found that phenol provided fast transformation of Pd+ to Pd0. Pd/ZS also can serve as an active and stable catalyst for 4-PhCl transformation to phenol after proper reduction.

A study is performed of bimetallic catalysts NiZn/ND with ratios Ni : Zn = 1 : 1 and 1 : 3 prepared by impregnation using detonation nanodiamond (ND) as a support. They were compared with monometallic Ni/ND and Zn/ND. It is shown by nitrogen adsorption/desorption, scanning and transmission electron microscopy that metal deposition does not affect the porous structure or morphology of a support. Coordination of metal precursors on a nanodiamond surface proceeds with the participation of functional groups, as is confirmed by a change in the electrokinetic charge of the surface. The reduction of metal precursors is studied by temperature-programmed reduction and in situ XAFS spectroscopy. In Ni-containing samples, two forms of Ni 2+ are found that are bonded differently with the support. ZnO is not reduced in the samples upon treatment with hydrogen at temperatures up to 400°C. The fraction of reduced nickel is determined by analyzing XANES spectra. Virtually full reduction of nickel is observed in a catalyst with a Ni : Zn ratio of 1 : 1 after 4 h of in situ treatment with hydrogen inside a spectrometer cell at 400°C, but not at a Ni : Zn ratio of 1 : 3 under the same conditions. The highest selectivity of styrene formation in the reaction of phenylacetylene hydrogenation throughout the investigated range of temperatures (100–350°С) is ensured by NiZn/ND; NiZn 3 /ND is less active and selective, since ZnO closes the active nickel centers and prevents the adsorption of phenylacetylene.

The physicochemical and catalytic properties of 6%Ni/Al2O3 catalysts in the gas-phase hydrodechlorination of chlorobenzene (CB) are studied. The catalysts are synthesized by supporting nickel nitrate on two types of alumina—A (synthesized by aluminum isopropoxide hydrolysis) and E (manufactured by Engelhard)—with different morphologies and textures; some of the samples are unmodified, and some are modified by depositing 20% heteropoly acid (HPA) H8Si(W2O7)6 ⋅ nH2O. To prevent the HPA from decomposition, the air calcining and reduction of the modified materials are conducted at relatively low temperatures (250 and 330°C, respectively). To provide an adequate comparison, the catalysts containing no HPA are subjected to a similar treatment. Temperature-programmed reduction (TPR) reveals that air calcining at 250°C does not provide the complete conversion of the original nickel nitrate to oxide; nickel nitrates and hydroxynitrates are present in the catalyst precursors; their content decreases upon modification with the HPA. Differences in the composition and strength of Lewis acid sites on the surface of two types of Al2O3 lead to dissimilar coordination of nitrate and differences in nickel reducibility, as revealed by TPR, diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy with CO adsorption, and in situ X-ray photoelectron spectroscopy (XPS). Nickel contained in Ni/Al2O3(E) undergoes reduction somewhat more readily than nickel in Ni/Al2O3(A) does; however, the conditions used in this study provide the reduction of only a small portion of nickel in the two catalysts. According to in situ XPS, TPR, and DRIFT spectroscopy with CO adsorption, the modification of Ni/Al2O3 with the HPA leads to a further change in the acidic properties and the coordination of nickel nitrate during impregnation and an increase in nickel reducibility; it prevents nickel from migration from the surface into the bulk of the sample and leads to the formation of new active sites owing to the strong nickel–tungsten interaction in the HPA. Depending on the nature of the support, modification with the HPA leads to an improvement (Ni/HPA/Al2O3(A)) or deterioration (Ni/HPA/Al2O3(E)) of the catalytic efficiency of the samples. At high temperatures, the benzene selectivity of the HPA-modified catalysts decreases owing to the formation of cyclohexane. The catalyst efficiency increases in the following order: Ni/HPA/Al2O3(E) < Ni/Al2O3(A) < Ni/Al2O3(E) < Ni/HPA/Al2O3(A). The most active catalyst—Ni/HPA/Al2O3(A)—exhibits the highest stability in long-term tests with an increase and subsequent decrease in temperature. The effect of nickel reducibility on the catalyst efficiency in CB hydrodechlorination is more significant than the effect of differences in texture and nickel content.