Ceria Promoted Cu-Ni/SiO2 Catalyst for Selective Hydrodeoxygenation of Vanillin

A ceria (CeO2) promoted Cu-Ni bimetallic catalyst supported on SiO2 (Cu-Ni/CeO2-SiO2) was prepared and evaluated for catalytic hydrodeoxygenation (HDO) of vanillin. Silica supported monometallic Cu and Ni catalysts and bimetallic Cu-Ni catalyst (Cu/SiO2, Ni/SiO2, and Cu-Ni/SiO2), without a ceria promoter, were also synthesized and tested for the same application. The highest conversion of vanillin was achieved with the Cu-Ni/CeO2-SiO2 catalyst. Vanillyl alcohol was the sole product in the initial 2 h, followed by the formation of 2-methoxy-4-methylphenol, which was observed. Characterization of the synthesized catalysts revealed the presence of overlapping crystalline phases of CuO, NiO, and CeO2 on the Cu-Ni/CeO2-SiO2 surface. We extended our study to find out the results of using CeO2 as the support of the Cu-Ni bimetallic catalyst (Cu-Ni/CeO2). Partial incorporation of Cu and Ni cations into the ceria lattice took place, leading to the decrease of specific surface area and a concomitant compromise in the conversion. In the case of the Cu-Ni/CeO2-SiO2 catalyst, the higher conversion was accredited to the facile formation of Cu+ active centers by the synergistic interaction between Ce+4/Ce+3 and Cu+2/Cu+ redox couples and the incorporation of oxygen vacancies on the catalyst surface.

Developmental trends in CO2 methanation using various catalysts

Co₂ methanation-two edged sword to counter global warming and energy crisis.

Nanostructured Nickel/Silica Catalysts for Continuous Flow Conversion of Levulinic Acid to γ-Valerolactone

Selective transformation of levulinic acid (LA) to γ-valerolactone (GVL) using novel heterogeneous catalysts is one of the promising strategies for viable biomass processing. In this framework, we developed a continuous flow process for the selective hydrogenation of LA to GVL using several nanostructured Ni/SiO₂ catalysts. The structural, textural, acidic, and redox properties of Ni/SiO₂ catalysts, tuned by selectively varying the Ni amount from 5 to 40 wt %, were critically investigated using numerous materials characterization techniques. Electron microscopy images showed the formation of uniformly dispersed Ni nanoparticles on the SiO₂ support, up to 30% Ni loading (average particle size is 9.2 nm), followed by a drastic increase in the particles size (21.3 nm) for 40% Ni-loaded catalyst. The fine dispersion of Ni particles has elicited a synergistic metal-support interaction, especially in 30% Ni/SiO₂ catalyst, resulting in enhanced acidic and redox properties. Among the various catalysts tested, the 30% Ni/SiO₂ catalyst showed the best performance with a remarkable 98% selectivity of GVL at complete conversion of LA for 2 h reaction time. Interestingly, this catalyst showed a steady selectivity to GVL (>97%), with a 54.5% conversion of LA during 20 h time-on-stream. The best performance of 30% Ni/SiO₂ catalyst was attributed to well-balanced catalytic properties, such as ample amounts of strong acidic sites and abundant active metal sites. The obtained results show a great potential of applying earth-abundant nickel/silica catalysts for upgrading biomass platform molecules into value-added chemicals and high-energy-density fuels.

Superior catalytic performance of a CoOx/Sn–CeO2 hybrid material for catalytic diesel soot oxidation

A Co₃O₄/Sn–CeO₂ hybrid catalyst exhibited superior soot oxidation activity due to the existence of synergism among the multivalent cations and the stepped surface of the hybrid catalyst.

Investigation on the physicochemical properties of Ce0.8Eu0.1M0.1O2−δ (M = Zr, Hf, La, and Sm) solid solutions towards soot combustion

The physicochemical properties of Ce–Eu-oxides were greatly improved by the introduction of trivalent or tetravalent metal cations into their lattice.

Novelty of Dynamic Process in the Synthesis of Biocompatible Silica Nanotubes by Biomimetic Glycyldodecylamide as a Soft Template

A dynamic process in the synthesis of silica nanotubes (SNTs) by utilizing glycyldodecylamide (GDA) as a soft template was thoroughly investigated. The morphological evolution from GDA to SNTs was deeply explored to elucidate the formation mechanism for optimizing the synthesis procedure. Various analytical tools, namely, XRD, FTIR, SEM, TEM, Z-potential, and N₂ adsorption/desorption isotherms, were employed during the synthesis procedure. The interactive structure of GDA was also investigated using TEM-EDX as a function of aging time. These studies revealed the stepwise morphology of nanograin, nanofiber, curved plate, and nanotube in the ethanol/water solution when aged at room temperature. The supramolecular GDA molded the vesicle type nanostructure which was surrounded by silica and facilitated the formation of uniform SNTs. The stimulus for GDA to be curved into a vesicle was the intermolecular hydrogen bonding between adjacent amide groups of the template molecules. This was illustrated by FTIR spectra of GDA-silica intermediate by detecting the transition of amide I peak from 1678 to 1635 cm^-1. The effect of hydrogen bonding became stronger when the sample was aged.

Nanowire Morphology of Mono- and Bidoped α-MnO2 Catalysts for Remarkable Enhancement in Soot Oxidation

In the present work, nanowire morphologies of α-MnO₂, cobalt monodoped α-MnO₂, Cu and Co bidoped α-MnO₂, and Ni and Co bidoped α-MnO₂ samples were prepared by a facile hydrothermal synthesis. The structural, morphological, surface, and redox properties of all the as-prepared samples were investigated by various characterization techniques, namely, scanning electron microscopy (SEM), transmission and high resolution electron microscopy (TEM and HR-TEM), powder X-ray diffraction (XRD), N₂ sorption surface area measurements, X-ray photoelectron spectroscopy (XPS), hydrogen-temperature-programmed reduction (H₂-TPR), and oxygen-temperature-programmed desorption (O₂-TPD). The soot oxidation performance was found to be significantly improved via metal mono- and bidoping. In particular, Cu and Co bidoped α-MnO₂ nanowires showed a remarkable improvement in soot oxidation performance, with its T₅₀ (50% soot conversion) values of 279 and 431 °C under tight and loose contact conditions, respectively. The soot combustion activation energy for the Cu and Co bidoped MnO₂ nanowires is 121 kJ/mol. The increased oxygen vacancies, greater number of active sites, facile redox behavior, and strong synergistic interaction were the key factors for the excellent catalytic activity. The longevity of Cu and Co bidoped α-MnO₂ nanowires was analyzed, and it was found that the Cu/Co bidoped α-MnO₂ nanowires were highly stable after five successive cycles and showed an insignificant decrease in soot oxidation activity. Furthermore, the HR-TEM analysis of a spent catalyst after five cycles indicated that the (310) crystal plane of α-MnO₂ interacts with the soot particles; therefore, we can assume that more-reactive exposed surfaces positively affect the reaction of soot oxidation. Thus, the Cu and Co bidoped α-MnO₂ nanowires provide promise as a highly effective alternative to precious metal based automotive catalysts.

Crucial role of titanium dioxide support in soot oxidation catalysis of manganese doped ceria

The influence of an anatase-TiO₂support on the diesel soot oxidation catalytic activity of manganese doped ceria is investigated.

Genomics era and complex disorders: Implications of GWAS with special reference to coronary artery disease, type 2 diabetes mellitus, and cancers

The Human Genome Project (HGP) has identified millions of single nucleotide polymorphisms (SNPs) and their association with several diseases, apart from successfully characterizing the Mendelian/monogenic diseases. However, the dissection of precise etiology of complex genetic disorders still poses a challenge for human geneticists. This review outlines the landmark results of genome-wide association studies (GWAS) with respect to major complex diseases - Coronary artery disease (CAD), type 2 diabetes mellitus (T2DM), and predominant cancers. A brief account on the current Indian scenario is also given. All the relevant publications till mid-2015 were accessed through web databases such as PubMed and Google. Several databases providing genetic information related to these diseases were tabulated and in particular, the list of the most significant SNPs identified through GWAS was made, which may be useful for designing studies in functional validation. Post-GWAS implications and emerging concepts such as epigenomics and pharmacogenomics were also discussed.

Low-temperature CO oxidation over manganese, cobalt, and nickel doped CeO2 nanorods

Transition metal doped ceria nanorods exhibit a better CO oxidation activity at lower temperatures.

Highly efficient continuous-flow oxidative coupling of amines using promising nanoscale CeO2–M/SiO2 (M = MoO3 and WO3) solid acid catalysts

Nanoscale CeO₂–MoO₃/SiO₂ solid acid shows an outstanding catalytic performance in the oxidative coupling of amines under industrially-favourable conditions.

Nanocrystalline alumina-supported ceria–praseodymia solid solutions: structural characteristics and catalytic CO oxidation

The synergistic effect between ceria–praseodymia and alumina support is responsible for the efficient CO oxidation activity of the catalyst owing to the enhanced surface area, oxygen vacancy concentration, and active oxygen species formation.

β-Cyclodextrin supported MoO3–CeO2 nanocomposite material as an efficient heterogeneous catalyst for degradation of phenol

The β-cyclodextrin supported MoO₃–CeO₂ nanocomposite material is an efficient heterogeneous catalyst for the degradation of phenol to non-toxic pollutants at room temperature with continuous stirring and without light irradiation.

Ceria–zirconia modified MnOx catalysts for gaseous elemental mercury oxidation and adsorption

The developed ceria–zirconia modified MnO_x catalysts were found to exhibit enhanced Hg⁰ oxidation and removal performance.

Highly efficient cerium dioxide nanocube-based catalysts for low temperature diesel soot oxidation: the cooperative effect of cerium- and cobalt-oxides

Co₃O₄ promoted CeO₂ nanocubes exhibit a remarkable catalytic activity for soot oxidation, attributed to the superior reducible nature of CeO₂ and the preferential exposure of CeO₂ (100) and Co₃O₄ (110) facets.

Experimental observation and theoretical investigation of a novel Cd(ii) complex with π-hole interactions involving nitro groups

A cadmium(ii) complex, which represents a novel example of supramolecular system bearing a network of π-hole interactions, has been synthesized.

Correlation between the structural characteristics, oxygen storage capacities and catalytic activities of dual-phase Zn-modified ceria nanocrystals

An excellent correlation between the structural properties and OSCs of dual-phase Zn-modified ceria nanocrystals is established. The detrimental effect of the secondary X-ray amorphous ZnO phase on soot oxidation is elucidated.

Highly efficient nanosized Mn and Fe codoped ceria-based solid solutions for elemental mercury removal at low flue gas temperatures

Mn and Fe codoped ceria-based solid solutions are effective catalysts for Hg⁰ removal at low flue gas temperatures.

Catalytic oxidation and adsorption of elemental mercury over nanostructured CeO2–MnOx catalyst

The presence of oxygen vacancies and synergetic interaction between Ce and Mn were responsible for superior Hg⁰ oxidation performance of CeO₂–MnO_x compared to pure CeO₂ and MnO_x.

Ce0.80M0.12Sn0.08O2−δ (M = Hf, Zr, Pr, and La) ternary oxide solid solutions with superior properties for CO oxidation

Ce_0.80Pr_0.12Sn_0.08O_2−δ combination catalyst exhibited highest CO oxidation activity owing to its high specific surface area, better reducibility, superior surface active oxygen species, and oxygen vacancies among various samples investigated.