Decomposition Of Metal Complexes Research Articles

Design, Synthesis, Structural Investigation and Photo Induced Biological Investigations of Co(II), Ni(II) and Cu(II) Complexes Derived from N,O Donor Schiff Bases.

A series of chelated metal complexes, [Co(LI)2] (1), [Ni(LI)2] (2), [Cu(LI)2] (3) [Co(LII)2] (4), [Ni(LII)2] (5) and [Cu(LII)2] (6) were designed and synthesized from newly synthesized Schiff bases, LI = 2-((E)-(5-(4-fluorophenyl)isoxazol-3-ylimino)methyl)-5-methylphenol and LII = 2-((E)-(5-(4-fluorophenyl)isoxazol-3-ylimino)methyl)-4-chlorophenol. The synthesized compounds were characterized by elemental analysis, nuclear magnetic resonance spectroscopy (NMR), electronic spectroscopy (UV-Vis), infrared spectroscopy (FT-IR), magnetic susceptibility (µeff), electron spin resonance spectroscopy (ESR), Thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and powder X-ray diffraction analysis (P-XRD). The spectral investigations have been clearly suggested 1:2 (metal: ligand) stoichiometric complexes with square planar geometrical arrangement around the metal ion. The thermal gravimmetric analysis (TGA) of these complexes indicates greater thermal stability and various steps involved in thermal decomposition of metal complexes. The binding ability between these metal complexes and calf thymus DNA (CT-DNA) was investigated by UV-Vis, fluorescence spectroscopy and viscometric experiments, which disclosed that, the complexes interacted to CT-DNA via an intercalation binding mode. The cleavage property of metal complexes against pBR322 DNA has been explored by gel electrophoresis technique mediated by UV-illumination and H2O2, showed momentous cleavage activity. Antioxidant activity of all complexes was determined by DPPH free radical scavenging experiment and showed prominent antioxidant activity. Further, the antibacterial and antifungal activities of all compounds were screened against bacterial and fungal strains via in-vitro disc diffusion method. These studies revealed that the complexes showed comparatively more antimicrobial activity than free ligands against tested microbial strains.

Enhanced pyrite passivation by carrier-microencapsulation using Fe-catechol and Ti-catechol complexes

Acid mine drainage (AMD) formation is mainly caused by the oxidation of pyrite. Carrier-microencapsulation (CME) using metal-catecholate complexes has been proposed to passivate sulfide minerals by forming surface-protective coatings on their surfaces. Among the various metal-catecholate complexes, Ti-catecholate formed stable coatings having superior acid-resistance, but a thick enough passivating film required considerable time (ca. 14 days) to grow. Meanwhile, Fe-catecholates can form Fe-oxyhydroxide coatings within 2 days, however, they are less stable than Ti-based coating. To address these drawbacks of using a single metal-complex, this study investigated the concurrent use of Fe-catechol and Ti-catechol complexes for accelerating the formation of stable passivating coating on pyrite.Compared with a single metal-complex system, the coating formation was significantly accelerated in mixed system. Linear sweep voltammetry showed the simultaneous decomposition of [Fe(cat)]+ and [Ti(cat)3]2– as the main reason for improved coating formation. Electrochemical properties of coatings formed by single and mixed complex systems, confirmed by electrochemical impedance spectroscopy and cyclic voltammetry, indicated the coating formed in the mixed system had higher resistance and more electrochemically inert than the other cases. The simultaneous use of Fe-catechol and Ti-catechol complexes enhanced pyrite passivation by accelerating metal-complex decomposition and forming more stable coating composed of Fe2TiO5.

Transformations of Ionic Nanocrystals via Full and Partial Ion Exchange Reactions.

ConspectusElaborate chemical synthesis methods allow the production of various types of inorganic nanocrystals (NCs) with uniform shape and size distributions. Many single-step synthesis approaches, such as the reduction of metal ions, the decomposition of metal complexes, double replacement reactions, and hydrolysis, have been adapted to promote the generation of monodisperse metal and ionic NCs. However, the question has become, how can we synthesize NCs with thermodynamically metastable phases or very complex structures? The transformation of already-synthesized NCs via elemental substitutions, such as ion exchange reactions for ionic NCs and galvanic replacement reactions for metal NCs, can overcome the difficulties facing conventional one-step syntheses. In particular, NC ion exchange reactions have been studied with numerous combinations of foreign ions and ionic NCs with various shapes. They have been investigated extensively because the reactions proceed under relatively mild conditions thanks to the large surface-to-volume ratio of the NCs relative to their bulk form. The functionality of the resulting ionic NCs, including semiconducting and plasmonic properties, can be easily tuned in a wide range, from the visible to near-infrared. Because anions generally have much larger ionic radii than cations within the frameworks of NCs, the cation exchange reactions proceed much faster than the anion exchange reactions. For ionic NCs above a critical size, the anion framework remains intact, and the original shape of the parent NCs is retained throughout the cation exchange reaction. In contrast, the anion exchange reaction often provides the new NCs with unique structures, such as hollow or anisotropically phase-segregated assemblies.This Account focuses on the full and partial ion exchange reactions involving ionic NCs, which have been thoroughly investigated by our group and others while highlighting important aspects such as the preservation of appearance and dimensions. First, we discuss how each type of ion exchange reaction progresses to understand the morphologies and crystal structures of their final products. This discussion is supported by emphasizing important examples, which help to explore the formation of NCs with thermodynamically metastable phases and complex structures, and other significant features of the ion exchange reactions leading to structure-specific functions. As a special case, we examine how the shape-dependent anionic framework (surface anion sublattice and stacking pattern) of polyhedral Cu2O NCs determines the crystalline structure of the anion-exchanged products of hollow CuxS NCs. In addition, we review the characteristic anion exchange behavior of metal halide perovskite NCs observed in our laboratory and other laboratories. Finally, a general outline of the transformation of NCs via ion exchange reactions and future prospects in this field are provided.

Investigation on Co(II), Ni(II), Cu(II) and Zn(II) complexes derived from quadridentate salen-type Schiff base: Structural characterization, DNA interactions, antioxidant proficiency and biological evaluation

Abstract Four mononuclear metal chelated complexes, [Co(L)] (1), [Ni(L)] (2), [Cu(L)] (3) and [Zn(L)] (4), were designed and synthesized from a novel quadridentate salen-type Schiff base ligand (H2L) derived from 2-hydroxy napthaldehyde and 4-fluoro-1,2-phenylenediamine. The chemical structures of synthesized compounds were fully characterized by various techniques. Spectral and analytical investigations clearly suggested that a square planar geometry around metal centre. The thermal analysis (TGA) of these complexes indicated greater thermal stability and various steps involved in thermal decomposition of metal complexes. The binding ability between the metal complexes and CT-DNA was investigated by UV-Vis, fluorescence spectroscopy and viscometric experiments which revealed an intercalation binding mode of binding. The cleavage property of metal complexes against pBR322 DNA has been explored. The antioxidant activity of M(II) complexes against active free radicals was determined by DPPH free radical scavenging experiment. Furthermore all compounds were screened against antimicrobial activity.

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Metal oxides are promising compounds for water-splitting systems toward hydrogen production. One of the most important methods to prepare nanosized metal oxides is the decomposition of metal complexes. Herein, different Mn oxides from the decomposition of β-cyclodextrin-Mn complex in different calcined temperatures were studied by scanning electron microscopy, thermal gravimetric analysis, X-ray diffraction and a few electrochemical methods. Using scanning electron microscopy, we propose a mechanism to answer to the question that how is Mn oxide formed by the decomposition of β-cyclodextrin-Mn complex.In the next step, usual chemometric methods, principal component analysis (PCA) and multivariate curve resolution-alternating least squares (MCR-ALS), were used to not only determine the number of components and data visualization, but also examine the square wave voltammograms of obtained Mn oxides from the decomposition of β-cyclodextrin-Mn complex. Water-oxidizing activities of the compounds under the presence of photo-produced Ru(bpy)33+ were also considered.

A new decomposition mechanism for metal complexes under water-oxidation conditions

Herein, water-oxidation reaction by cobalt(II) phthalocyanine, N,N′-bis (salicylidene) ethylenediamino cobalt(II), nickel(II) Schiff base (N,N′-bis (salicylidene)ethylenediamino nickel(II), nickel(II)) phthalocyanine-tetrasulfonate tetrasodium, manganese(II) phthalocyanine, 5,10,15,20-Tetraphenyl-21H,23H-porphine manganese(III) chloride, manganese(III) 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine chloride tetrakis(methochloride) was investigated using electrochemistry, UV-vis spectroscopy and spectroelectrochemistry. According to our results, a new decomposition pathway for these metal complexes under water-oxidation conditions was proposed. The produced metal oxide obtained by decomposition of metal complex under water -oxidation conditions not only catalyzes water-oxidation reaction but this metal oxide also accelerates decomposition of the corresponding complex to form higher amounts of the metal oxide. We hypothesize that such a mechanism could be investigated for many metal complexes under different oxidation or reduction reactions.

Recent Advances in the Chemistry of N‐Heterocyclic‐Carbene‐Functionalized Metal‐Nanoparticles and Their Applications

Metal‐nanoparticles (M‐NPs) have been widely applied in catalysis, imaging, sensing and medicine. One particularly active area of this research is the modification of the surface of the nanoparticles to prevent aggregation through the coordination of ligands. N‐Heterocyclic carbenes (NHCs) have emerged as suitable ligands for this purpose due to their affinity to the metals and their strongly electron donating nature. A number of rationally designed NHC‐modified M‐NPs have been developed using strategies based on metal complex decomposition and ligand exchange. Herein, NHC‐stabilized M‐NPs based on a range of transition metals, especially the recent advances, were summarized.

Novel luminescent PLA/MgAl2O4:Sm3+ composite filaments for 3D printing application

In this work, luminescent bioplastic composite filaments for 3D printing were fabricated from polylactic acid (PLA) and samarium doped magnesium aluminate phosphor (MgAl2O4:Sm3+). The phosphor was prepared by a metal-complex decomposition method. The obtained powder was then modified by 3-aminopropyl triethoxysilane to improve compatibility with PLA matrix. Untreated and treated phosphors exhibited characteristic photoluminescent (PL) peaks of Sm3+ ion. Composite filaments of PLA with different amounts of phosphors (0, 1, 2, 3 and 4 phr) were produced by an extrusion process. Differential scanning calorimetry (DSC) scans have revealed that the phosphor fillers lowered glass-transition (Tg), crystallization (Tc), and melting (Tm) temperatures of the PLA. PL measurements have shown luminescent properties of 3D printed samples resembling those of phosphor powders. Luminescent intensity was increased with the increasing ratio of phosphors. The phosphors not only developed luminescence but also strengthened mechanical properties of the composites. Furthermore, surface modification was able to improve the mechanical properties of the composite filaments as evident in a series of mechanical tests.

Physiochemical properties of greatly enhanced photoluminescence of aqueous dispersible upconversion CaF2:Yb/Er nanoparticles.

Crystal phase morphological structure and optical properties of the as-prepared upconversion CaF2:Yb/Er(core) and sequential coating of an inert crystalline material and silica layers surrounding the seed core-nanoparticles (NPs) were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), optical absorption, FTIR spectroscopy and upconversion photoluminescence spectroscopy. Owing to the unique properties of CaF2 host matrix, we realized their practical applications in biomedical science to improve the upconversion luminescence property and aqueous dispersibility. The surface coating on the seed core particles will significantly influence the structural, optical band gap energy and upconversion luminescence properties. These NPs were well-dispersed in aqueous and non-aqueous solvents to form clear colloidal solutions. The colloidal solutions of three samples show a characteristic optical absorption band in UV/Visible region. As a result, optical band gap gradually decreases after sequential growth of the inert shell and amorphous silica due to an increase in the crystalline size. Comparative upconversion luminescence analysis showed that after inert shell growth, the upconversion intensity was greatly improved, and such an improvement was found to arise from efficient suppression of surface-related deactivation from the core nanocrystals. Interestingly, growth of an inert (CaF2) shell over the seed core NPs shows intense upconversion emission lines under 980 nm NIR laser excitation, highlighting their promising applications, such as multi-analyte biolabels, staining, displays and other photonic based technological applications.

A proposed mechanism to form nanosized Mn oxides from the decomposition of β-cyclodextrin-Mn complex: Toward nanosized water-splitting catalysts with special morphology

Metal oxides are promising compounds for water-splitting systems toward hydrogen production. One of the most important methods to prepare nanosized metal oxides is the decomposition of metal complexes. Herein, different Mn oxides from the decomposition of β-cyclodextrin-Mn complex in different calcined temperatures were studied by scanning electron microscopy, thermal gravimetric analysis, X-ray diffraction and a few electrochemical methods. Using scanning electron microscopy, we propose a mechanism to answer to the question that how is Mn oxide formed by the decomposition of β-cyclodextrin-Mn complex.In the next step, usual chemometric methods, principal component analysis (PCA) and multivariate curve resolution-alternating least squares (MCR-ALS), were used to not only determine the number of components and data visualization, but also examine the square wave voltammograms of obtained Mn oxides from the decomposition of β-cyclodextrin-Mn complex. Water-oxidizing activities of the compounds under the presence of photo-produced Ru(bpy)33+ were also considered.

Preparation of Palladium-Impregnated Ceria by Metal Complex Decomposition for Methane Steam Reforming Catalysis

Palladium-impregnated ceria materials were successfully prepared via an integrated procedure between a metal complex decomposition method and a microwave-assisted wetness impregnation. Firstly, ceria (CeO2) powders were synthesized by thermal decomposition of cerium(III) complexes prepared by using cerium(III) nitrate or cerium(III) chloride as a metal source to form a metal complex precursor with triethanolamine or benzoxazine dimer as an organic ligand. Palladium(II) nitrate was consequently introduced to the preformed ceria materials using wetness impregnation while applying microwave irradiation to assist dispersion of the dopant. The palladium-impregnated ceria materials were obtained by calcination under reduced atmosphere of 10% H2 in He stream at 700°C for 2 h. Characterization of the palladium-impregnated ceria materials reveals the influences of the metal complex precursors on the properties of the obtained materials. Interestingly, the palladium-impregnated ceria prepared from the cerium(III)-benzoxazine dimer complex revealed significantly higher BET specific surface area and higher content of the more active Pdδ+ (δ > 2) species than the materials prepared from cerium(III)-triethanolamine complexes. Consequently, it exhibited the most efficient catalytic activity in the methane steam reforming reaction. By optimization of the metal complex precursors, characteristics of the obtained palladium-impregnated ceria catalysts can be modified and hence influence the catalytic activity.

A facile synthesis approach and impact of shell formation on morphological structure and luminescent properties of aqueous dispersible NaGdF4:Yb/Er upconversion nanorods

A general facile synthesis approach was used for fabrication of highly emissive aqueous dispersible hexagonal phase upconversion luminescent NaGdF4:Yb/Er nanorods (core NRs) through metal complex decomposition process. An inert NaGdF4 and porous silica layers were grafted surrounding the surface of each and every NRs to enhance their luminescence efficiency and colloidal dispersibility in aqueous environment. Optical properties in terms of band gap energy of core, core/shell, and silica-coated core/shell/SiO2 nanorods were observed to investigate the influence of surface coating, which was gradually decreased after surface coating because of increase crystalline size after growth of inert and silica shells. The inert shell formation before silica surface grafting, upconversion luminescence intensity was greatly improved by about 20 times, owing to the effective surface passivation of the seed core and, therefore, protection of Er3+ ion in the core from the nonradiative decay caused by surface defects. Moreover, after silica coating, core/shell nanorods shows strong upconversion luminescence property similar to the hexagonal upconversion core NRs. It is expected that these NaGdF4:Yb/Er@NaGdF4@SiO2 (core/shell/SiO2) NRs including highly upconversion emissive and aqueous dispersible properties make them an ideal materials for various photonic-based potential applications such as in upconversion luminescent bioimaging, magnetic resonance imaging, and photodynamic therapy.

Highly aqueous soluble CaF2:Ce/Tb nanocrystals: effect of surface functionalization on structural, optical band gap, and photoluminescence properties.

The design of nanostructured materials with highly stable water-dispersion and luminescence efficiency is an important concern in nanotechnology and nanomedicine. In this paper, we described the synthesis and distinct surface modification on the morphological structure and optical (optical absorption, band gap energy, excitation, emission, decay time, etc.) properties of highly crystalline water-dispersible CaF2:Ce/Tb nanocrystals (core-nanocrystals). The epitaxial growth of inert CaF2 and silica shell, respectively, on their surface forming as CaF2:Ce/Tb@CaF2 (core/shell) and CaF2:Ce/Tb@CaF2@SiO2 (core/shell/SiO2) nanoarchitecture. X-ray diffraction and transmission electron microscope image shows that the nanocrystals were in irregular spherical phase, highly crystalline (~20 nm) with narrow size distribution. The core/shell nanocrystals confirm that the surface coating is responsible in the change of symmetrical nanostructure, which was determined from the band gap energy and luminescent properties. It was found that an inert inorganic shell formation effectively enhances the luminescence efficiency and silica shell makes the nanocrystals highly water-dispersible. In addition, Ce3+/Tb3+-co-doped CaF2 nanocrystals show efficient energy transfer from Ce3+ to Tb3+ ion and strong green luminescence of Tb3+ ion at 541 nm(5D4→7F5). Luminescence decay curves of core and core/shell nanocrystals were fitted using mono and biexponential equations, and R 2 regression coefficient criteria were used to discriminate the goodness of the fitted model. The lifetime values for the core/shell nanocrystals are higher than core-nanocrystals. Considering the high stable water-dispersion and intensive luminescence emission in the visible region, these luminescent core/shell nanocrystals could be potential candidates for luminescent bio-imaging, optical bio-probe, displays, staining, and multianalyte optical sensing. A newly designed CaF2:Ce/Tb nanoparticles via metal complex decomposition rout shows high dispersibility in aqueous solvents with enhanced photoluminescence. The epitaxial growth of inert CaF2 shell and further amorphous silica, respectively, enhanced their optical and luminescence properties, which is highly usable for luminescent biolabeling, and optical bioprobe etc.

An investigation into the formation and conversion of metal complexes to metal oxide nanoparticles in supercritical water

Due to unavoidable formation of metal complexes derived from nitrate solutions in high temperature water, the current research aimed at study on such intermediates in order to find the best condition for the complex-free synthesis of metal oxides in supercritical water (SCW). Here, aqueous solutions of several metal nitrate salts including zinc(II), copper(II), manganese(II), cerium(III), magnesium(II), nickel(II), silver(I), and zirconium(IV) have been treated as the precursors for the metal oxide nanoparticle synthesis in a batchwise SCW reactor. The experiments were conducted at two temperatures with different reaction properties, near-critical condition (400°C) in which water preserves its ionic properties relative to the second point with higher temperature (500°C) that the mechanism of reaction inclines to the free radical mechanism due to the falling of dielectric constant (ɛ). Based on the results of X-ray diffractometry (XRD), Fourier-transform infrared (FTIR) spectra, and thermogravimetric analysis (TGA), it was revealed that some nitrate, hydroxide, and especially hydoxynitrates complexes with ionic origins through their synthesis path, as the byproducts of metal oxide formation reaction, were formed at low temperatures. However, these complexes decomposed into the metal oxide nanoparticles at higher temperature. Complementary experiments on copper nitrate solution showed that temperature is a key parameter in the formation and decomposition of metal complexes in the SCW treatment of metal nitrate solutions used in this research work. Finally, a general mechanism describing the formation and conversion of metal complexes during the treatment of aforementioned metal nitrate solutions and, consequently, synthesis of metal oxide nanoparticles was suggested.

Synthesis, Characterization, and Nanocatalysis Application of Core–Shell Superparamagnetic Nanoparticles of Fe3O4@Pd

There is a wide number of different synthetic methods to obtain magnetite (Fe3O4) superparamagnetic nanoparticles (SPNPs). However, only a few are able to produce very small and well defined SPNPs with narrow size distribution. We report a modification of the metal-complex decomposition in organic media method in which we replace iron(iii) acetylacetonate (Fe(Acac)3) with an iron–urea complex (Fe-Urea) as metal source for the synthesis. With this modification we were able to obtain small particle sizes with a good control in size distribution. The Fe-Urea complex is easy to prepare with excellent yields. Core–shell nanoparticles are then prepared using palladium(ii) acetylacetonate as a Pd source, to obtain a Pd0 shell stabilised by oleylamine. The core–shell superparamagnetic nanoparticles of Fe3O4@Pd-OA are extensively characterized by FT-IR, powder X-ray diffraction, transmission electron microscopy, UV-vis, thermogravimetric analysis/differential scanning calorimetry, and magnetic susceptibility measurements, and tested in a palladium-catalyzed cross-coupling Suzuki–Miyaura reaction with promising results.

Activity of Fe supported by Ce1−xSmxO2−δ derived from metal complex decomposition toward the steam reforming of toluene as biomass tar model compound

Ceria (CeO2) and samaria doped ceria (Ce1−xSmxO2−δ) powders with various Ce/Sm ratios have been successfully prepared via metal complex decomposition. The catalytic activities of these synthesized materials toward the steam reforming of toluene as model compound of biomass tar were studied with an aim to determine the suitable catalyst for biomass tar decomposition in biomass gasification system. From the study, H2, CO, CO2, CH4, C2H4 and C2H6 were the main products from the reaction with low carbon deposition observed on the catalyst surface after 18 h operation. Among all catalysts, relatively higher toluene conversion and H2 yield (32.8%) with greater resistance toward carbon deposition was achieved from Ce0.85Sm0.15O2−δ. To enhance better toluene conversion and H2 yield, Ce0.85Sm0.15O2−δ was further applied as the catalyst support by impregnating low-cost Fe on its surface; and its reforming activity was compared to Ni and Fe supported over conventional γ-Al2O3. It was found that, Fe/Ce0.85Sm0.15O2−δ offered significantly higher toluene conversion and H2 yield than Fe/Al2O3 (55.2% H2 yield compared to 16.5%). Its reforming activity was also comparable to Ni/Al2O3 with better H2 yield stability after 72 h operation (16% deactivation for Fe/Ce0.85Sm0.15O2−δ compared to 35% deactivation for Ni/Al2O3). Therefore, Fe/Ce0.85Sm0.15O2−δ has good potential to replace Ni-based catalyst in biomass gasification system.

Formation of small volatile complexes during copper film growth by the combined synthesis-transport method

Stable heterogeneous synthesis products in combined synthesis-transport processes for the growth of thin copper films have been studied by ESR, X-ray photoelectron, and IR spectroscopies. The results demonstrate that the synthesized volatile compounds condensed on solid surfaces have the form of formate-like metal complexes of copper(I). We have identified the mechanisms underlying the formation of volatile monomeric metal complexes on the surface of copper-containing precursor particles and the mechanism of the thermal decomposition of metal complexes on a heated substrate.

High Exchange Bias in Fe3−δO4@CoO Core Shell Nanoparticles Synthesized by a One-Pot Seed-Mediated Growth Method

Core–shell nanoparticles (NPs), which consist in a ferrimagnetic (FIM)/antiferromagnetic (AFM) interface and result in exchange bias coupling, became recently of primary importance in the field of magnetic nanoparticles. The enhancement of some applications such as hyperthermia or magnetic storage media based on the miniaturization of devices is correlated to the size reduction of NPs, which results in the decrease of the magnetocrystalline anisotropy and of the blocking temperature. We present here the synthesis of Fe3−δO4@CoO core–shell NPs by a one-pot seed-mediated growth process based on the thermal decomposition of metal complexes at high temperature. A 2 nm thick CoO shell was grown homogeneously from the starting Fe3−δO4 core surface. The Fe3−δO4@CoO core–shell NP structure has been deeply investigated by performing XRD and advanced techniques based on TEM such as EELS and EFTEM. The high quality of the core–shell interface resulted in the large exchange bias coupling at 5 K (HE ≈ 4.1 kOe) between the FIM and the AFM components. In comparison to starting Fe3−δO4 NPs, the dramatic enhancement of the magnetic properties such as a high coercive field (at 5 K, HC ≈ 15 kOe) were measured. Furthermore, the core–shell structure resulted in the enhancement of the magnetocrystalline anisotropy and the increase of the blocking temperature to 293 K.

The Mechanism of Alkene Addition to a Nickel Bis(dithiolene) Complex: The Role of the Reduced Metal Complex

The binding of an alkene by Ni(tfd)(2) [tfd = S(2)C(2)(CF(3))(2)] is one of the most intriguing ligand-based reactions. In the presence of the anionic, reduced metal complex, the primary product is an interligand adduct, while in the absence of the anion, dihydrodithiins and metal complex decomposition products are preferred. New kinetic (global analysis) and computational (DFT) data explain the crucial role of the anion in suppressing decomposition and catalyzing the formation of the interligand product through a dimetallic complex that appears to catalyze alkene addition across the Ni-S bond, leading to a lower barrier for the interligand adduct.

Preparation of gadolinia doped ceria via metal complex decomposition method: Its application as catalyst for the steam reforming of ethane

The ceria (CeO2) and gadolinia doped ceria (GDC; Ce1−xGdxO2−δ with x=0.10, 0.15, and 0.20) catalysts were successfully prepared via metal complex decomposition method at 900°C for 2h. The synthesized CeO2 and GDC were found to have useful activity to convert ethane to syngas via the steam reforming reaction at the temperature range of 800–900°C. The catalytic activity was improved with increasing Gd doping amount from 0 to 0.1 and 0.15; nevertheless, at higher Gd doping content (0.2), the improvement becomes less pronounced. Among all catalysts, Ce0.85Gd0.15O2−δ showed the best steam reforming activity; furthermore, the amount of carbon formation over this catalyst was relatively low. These enhancements are mainly due to the high specific surface area and the good oxygen storage capacity (OSC) of the material. During the steam reforming process, the gas–solid reactions between the gaseous components presented in the system (C2H6, C2H4, and CH4) and the lattice oxygen (Ox) on the surface CeO2 or GDC occurs. The reactions of hydrocarbons adsorbed on the surface with Ox (CnHm+Ox→nCO+m/2(H2)+Ox−n) can prevent the formation of carbon species from hydrocarbons decomposition reaction (CnHm⇔nC+m/2H2). Moreover, the formation of carbon via Boudouard reaction (2CO⇔CO2+C) is also reduced by the gas–solid reaction of CO with the lattice oxygen (CO+Ox⇔CO2+Ox−1).