Selective oxidation of methane to synthesis gas using transition metal catalysts

Atomically dispersed MoNi alloy catalyst for partial oxidation of methane

The catalytic partial oxidation of methane (POM) presents a promising technology for synthesizing syngas. However, it faces severe over-oxidation over catalyst surface. Attempts to modify metal surfaces by incorporating a secondary metal towards C-H bond activation of CH4 with moderate O* adsorption have remained the subject of intense research yet challenging. Herein, we report that high catalytic performance for POM can be achieved by the regulation of O* occupation in the atomically dispersed (AD) MoNi alloy, with over 95% CH4 conversion and 97% syngas selectivity at 800 °C. The combination of ex-situ/in-situ characterizations, kinetic analysis and DFT (density functional theory) calculations reveal that Mo-Ni dual sites in AD MoNi alloy afford the declined O2 poisoning on Ni sites with rarely weaken CH4 activation for partial oxidation pathway following the combustion reforming reaction (CRR) mechanism. These results underscore the effectiveness of CH4 turnovers by the design of atomically dispersed alloys with tunable O* adsorption.

Observation of induction period and oxygenated intermediates in methane oxidation over Pt catalyst

Selective oxidation of methane is one of the most attractive routes for methane to chemicals. However, mechanistic understanding and avoiding over-oxidation have great challenges because of its very rapid reaction rate. Herein, a capillary micro-reaction system was introduced to monitor the initial stage of methane oxidation over platinum. For the first time, an induction period is observed, during which oxygenated intermediates, such as methanol, acetone, methyl methoxy acetate, etc., are detected. Induction period can be shortened by methane pretreatment at 600°C, which generates highly active species containing unsaturated bonds. Combined these findings and observations of in situ characterizations, the evolution route of methane oxidation over Pt is prosed, i.e., the reaction starts from the formation of initial species containing Pt-C bond, followed by the generation of oxygenated intermediates, and ended with the over-oxidation of the intermediates to CO/CO2.

Mechanistic Understanding of the Use of Single-Atom and Nanocluster Catalysts for Syngas Production via Partial Oxidation of Methane

Single-atom and nanocluster catalysts presenting potent catalytic activity and excellent stability are used in high-temperature applications such as in structural composites, electrical devices, and catalytic chemical reactions. Recently, more attention has been drawn to application of these materials in clean fuel processing based on oxidation in terms of recovery and purification. The most popular media for catalytic oxidation reactions include gas phases, pure organic liquid phases, and aqueous solutions. It has been proven from the literature that catalysts are frequently selected as the finest in regulating organic wastewater, solar energy utilization, and environmental treatment applications in most catalytic oxidation of methane vis-à-vis photons and in environmental treatment applications. Single-atom and nanocluster catalysts have been engineered and applied in catalytic oxidations considering metal-support interactions and mechanisms facilitating catalytic deactivation. In this review, the present improvements on engineering single-atom and nano-catalysts are discussed. In detail, we summarize structure modification strategies, catalytic mechanisms, methods of synthesis, and application of single-atom and nano-catalysts for partial oxidation of methane (POM). We also present the catalytic performance of various atoms in the POM reaction. Full knowledge of the use of remarkable POM vis-à-vis the excellent structure is revealed. Based on the review conducted on single-atom and nanoclustered catalysts, we conclude their viability for POM reactions; however, the catalyst design must be carefully considered not only for isolating the individual influences from the active metal and support but also for incorporating the interactions of these components.

Nitric Oxide Decomposition via Selective Catalytic Reduction by Ammonia on a Transition-Metal Cluster of W2TcO6

Decomposition of nitric oxide (NO) gas on a reactive transition-metal cluster of W₂TcO₆ has been examined and investigated via selective catalytic reduction by ammonia (NH₃-SCR) using the M06-L density functional method. The transition-metal cluster of W₂TcO₆ can be employed to transform NO to N₂ gas efficiently over an active site of tungsten (W). A reaction mechanism of NO conversion based on the NH₃-SCR process has been elucidated by a potential energy surface along the reaction pathways. The reaction pathways of this NH₃-SCR process begin with adsorption of NH₃, adsorption of NO to the cluster, formation of nitrosamine (NH₂NO) and NHNO/NHNOH intermediates, and rearrangement of NHNO/NHNOH to obtain N₂ and H₂O, respectively. Notably, a significant NH₂NO as a key intermediate, namely, "nitrosamine", must be formed before further steps can take place in the generation of N₂ from NO, followed by the involvement of the NHNO or NHNOH intermediate. From our calculated results, the NHNO intermediate via TS3a is found in pathway a, while NHNOH is found in pathway b via TS3b. Pathway b has a lower energy barrier of 35.1 kcal/mol than pathway a with an energy barrier of 41.8 kcal/mol, indicating that pathway b should be more energetically favorable. The step for NHNO intermediate rearrangement is a rate-determining step for the reaction occurring through pathway a, which is found to be more difficult in accordance with a difficult N-H bond cleavage to form the NNOH intermediate before N₂ formation. The overall reaction is an exothermic process with thermodynamic and kinetic favors. Thus, this bimetallic W₂TcO₆ cluster could be used as a promising and active catalyst for NO decomposition via the NH₃-SCR process to an eco-friendly gas, that is, N₂.

Recovery and utilization of crude glycerol, a biodiesel byproduct

Biodiesel production has increased significantly in the past decade because it has been demonstrated to be a viable alternative and renewable fuel. Consequently, the production of crude glycerol, the main byproduct of the transesterification of lipids to biodiesel, has risen as well. Therefore, the effective recovery and utilization of crude glycerol can provide biodiesel with additional value. In this review, we first summarized the state-of-the-art progress on crude glycerol recovery and purification. Subsequently, numerous approaches have been reviewed for the utilization of crude glycerol, including use as animal feeds, for combustion, anaerobic fermentation, and chemical conversion. Finally, an extensive discussion and outlook is presented in relation to the techniques and processes in the chemical conversion of crude glycerol.

In this review, we summarize the latest technologies for the recovery and purification of crude glycerol and applications of crude glycerol, with focus on its chemical conversion.

Single-Atom High-Temperature Catalysis on a Rh1O5 Cluster for Production of Syngas from Methane

Single-atom catalysts are a relatively new type of catalyst active for numerous reactions but mainly for chemical transformations performed at low or intermediate temperatures. Here we report that singly dispersed Rh₁O₅ clusters on TiO₂ can catalyze the partial oxidation of methane (POM) at high temperatures with a selectivity of 97% for producing syngas (CO + H₂) and high activity with a long catalytic durability at 650 °C. The long durability results from the substitution of a Ti atom of the TiO₂ surface lattice by Rh₁, which forms a singly dispersed Rh₁ atom coordinating with five oxygen atoms (Rh₁O₅) and an undercoordinated environment but with nearly saturated bonding with oxygen atoms. Computational studies show the back-donation of electrons from the d_z² orbital of the singly dispersed Rh₁ atom to the unoccupied orbital of adsorbed CH_n (n > 1) results in the charge depletion of the Rh₁ atom and a strong binding of CH_n to Rh₁. This strong binding decreases the barrier for activating C-H, thus leading to high activity of Rh₁/TiO₂. A cationic Rh₁ single atom anchored on TiO₂ exhibits a weak binding to atomic carbon, in contrast to the strong binding of the metallic Rh surface to atomic carbon. The weak binding of atomic carbon to Rh₁ atoms and the spatial isolation of Rh₁ on TiO₂ prevent atomic carbon from coupling on Rh₁/TiO₂ to form carbon layers, making Rh₁/TiO₂ resistant to carbon deposition than supported metal catalysts for POM. The highly active, selective, and durable high-temperature single-atom catalysis performed at 650 °C demonstrates an avenue of application of single-atom catalysis to chemical transformations at high temperatures.

Propane Steam Reforming over Catalysts Derived from Noble Metal (Ru, Rh)-Substituted LaNiO3 and La0.8Sr0.2NiO3 Perovskite Precursors

The propane steam reforming (PSR) reaction was investigated over catalysts derived from LaNiO₃ (LN), La_0.8Sr_0.2NiO₃ (LSN), and noble metal-substituted LNM_x and LSNM_x (M = Ru, Rh; x = 0.01, 0.1) perovskites. The incorporation of foreign cations in the A and/or B sites of the perovskite structure resulted in an increase in the specific surface area, a shift of XRD lines toward lower diffraction angles, and a decrease of the mean primary crystallite size of the parent material. Exposure of the as-prepared samples to reaction conditions resulted in the in situ development of new phases including metallic Ni and La₂O₂CO₃, which participate actively in the PSR reaction. The LN-derived catalyst exhibited higher activity compared to LSN, and its performance for the title reaction did not change appreciably following partial substitution of Ru for Ni. In contrast, incorporation of Ru and, especially, Rh in the LSN perovskite matrix resulted in the development of catalysts with significantly enhanced catalytic performance, which improved by increasing the noble metal content. The best results were obtained for the LSNRh_0.1-derived sample, which exhibited excellent long-term stability for 40 hours on stream as well as high propane conversion (X_C3H8 = 92%) and H₂ selectivity (S_H2 = 97%) at 600 °C.

Low-Temperature Methane Partial Oxidation over Pd Supported on CeO2: Effect of the Preparation Method and Precursors

The catalytic production of syngas by the partial oxidation of methane (POM) was investigated over Pd supported on ceria (0.5–2 Pd wt.%) prepared by incipient wetness impregnation and by mechanochemical methods. The performance of the Pd/CeO2 catalyst prepared by milling CeO2 and Pd acetate was superior to that prepared by milling CeO2 and Pd nitrate and to Pd/CeO2 prepared by impregnation from Pd acetate. The best catalytic activity of the Pd/CeO2 catalyst prepared from CeO2 and Pd acetate was obtained by milling at 50 Hz for 5 min. Two-step combustion and reforming reaction mechanism were identified. Remarkably, methane conversion increased progressively with Pd loading for the catalysts prepared by incipient wetness impregnation, whereas low metal loading showed better conversion of methane for the catalysts prepared by ball milling using Pd acetate. This was explained in terms of an impressive dispersion of Pd species with a strong interaction with the surface of ceria, as deduced from transmission electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy characterization, which revealed a large quantity of highly oxidized species at the surface.

Theoretical insights into C-H bond activation of methane by transition metal clusters: the role of anharmonic effects

In heterogeneous catalysis, the determination of active phases has been a long-standing challenge, as materials' properties change under operational conditions (i.e. temperature (T) and pressure (p) in an atmosphere of reactive molecules). As a first step towards materials design for methane activation, we study the T and p dependence of the composition, structure, and stability of metal oxide clusters in a reactive atmosphere at thermodynamic equilibrium using a prototypical model catalyst having wide practical applications: free transition metal (Ni) clusters in a combined oxygen and methane atmosphere. A robust methodological approach is employed, where the starting point is systematic scanning of the potential energy surface (PES) to obtain the global minimum structures using a massively parallel cascade genetic algorithm (cGA) at the hybrid density functional level. The low energy clusters are further analyzed to estimate their thermodynamic stability at realistic T, p _O2 and p _CH4 using ab initio atomistic thermodynamics (aiAT). To incorporate the anharmonicity in the vibrational free energy contribution to the configurational entropy, we evaluate the excess free energy of the clusters numerically by a thermodynamic integration method with ab initio molecular dynamics (aiMD) simulation inputs. By analyzing a large dataset, we show that the conventional harmonic approximation miserably fails for this class of materials, and capturing the anharmonic effects on the vibration free energy contribution is indispensable. The latter has a significant impact on detecting the activation of the C-H bond, while the harmonic infrared spectrum fails to capture this, due to the wrong prediction of the vibrational modes.

Non-Thermal Plasma for Process and Energy Intensification in Dry Reforming of Methane

Plasma-assisted dry reforming of methane (DRM) is considered as a potential way to convert natural gas into fuels and chemicals under near ambient temperature and pressure; particularly for distributed processes based on renewable energy. Both catalytic and photocatalytic technologies have been applied for DRM to investigate the CH4 conversion and the energy efficiency of the process. For conventional catalysis; metaldoped Ni-based catalysts are proposed as a leading vector for further development. However; coke deposition leads to fast deactivation of catalysts which limits the catalyst lifetime. Photocatalysis in combination with non-thermal plasma (NTP), on the other hand; is an enabling technology to convert CH4 to more reactive intermediates. Placing the catalyst directly in the plasma zone or using post-plasma photocatalysis could generate a synergistic effect to increase the formation of the desired products. In this review; the recent progress in the area of NTP-(photo)catalysis applications for DRM has been described; with an in-depth discussion of novel plasma reactor types and operational conditions including employment of ferroelectric materials and nanosecond-pulse discharges. Finally, recent developments in the area of optical diagnostic tools for NTP, such as optical emission spectroscopy (OES), in-situ FTIR, and tunable diode laser absorption spectroscopy (TDLAS), are reviewed.

Zeolite-supported ultra-small nickel as catalyst for selective oxidation of methane to syngas

The development of simple catalysts with high performance in the selective oxidation of methane to syngas at low temperature has attracted much attention. Here we report a nickel-based solid catalyst for the oxidation of methane, synthesised by a facile impregnation method. Highly dispersed ultra-small NiO particles of 1.6 nm in size are successfully formed on the MOR-type zeolite. The zeolite-supported nickel catalyst gives continuously 97-98% methane conversion, 91-92% of CO yield with a H₂/CO ratio of 2.0, and high durability without serious carbon deposition onto the catalyst at 973 K. DFT calculations demonstrate the effect of NiO particle size on the C-H dissociation process of CH₄. A decrease in the NiO particle size enhances the production of oxygen originating from the NiO nanoparticles, which contributes to the oxidation of methane under a reductive environment, effectively producing syngas.

Ceria-Based Catalysts Studied by Near Ambient Pressure X-ray Photoelectron Spectroscopy: A Review

The development of better catalysts is a passionate topic at the forefront of modern science, where operando techniques are necessary to identify the nature of the active sites. The surface of a solid catalyst is dynamic and dependent on the reaction environment and, therefore, the catalytic active sites may only be formed under specific reaction conditions and may not be stable either in air or under high vacuum conditions. The identification of the active sites and the understanding of their behaviour are essential information towards a rational catalyst design. One of the most powerful operando techniques for the study of active sites is near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS), which is particularly sensitive to the surface and sub-surface of solids. Here we review the use of NAP-XPS for the study of ceria-based catalysts, widely used in a large number of industrial processes due to their excellent oxygen storage capacity and well-established redox properties.

Partial Oxidation of Methane to Syngas Over Nickel-Based Catalysts: Influence of Support Type, Addition of Rhodium, and Preparation Method

There is great economic incentive in developing efficient catalysts to produce hydrogen or syngas by catalytic partial oxidation of methane (CPOM) since this is a much less energy-intensive reaction than the highly endothermic methane steam reforming reaction, which is the prominent reaction in industry. Herein, we report the catalytic behavior of nickel-based catalysts supported on different oxide substrates (Al₂O₃, CeO₂, La₂O₃, MgO, and ZrO₂) synthesized via wet impregnation and solid-state reaction. Furthermore, the impact of Rh doping was investigated. The catalysts have been characterized by X-ray diffraction, N₂ adsorptiondesorption at −196°C, temperature-programmed reduction, X-ray photoelectron spectroscopy, O₂-pulse chemisorption, transmission electron microscopy, and Raman spectroscopy. Supported Ni catalysts were found to be active for CPOM but can suffer from fast deactivation caused by the formation of carbon deposits as well as via the sintering of Ni nanoparticles (NPs). It has been found that the presence of Rh favors nickel reduction, which leads to an increase in the methane conversion and yield. For both synthesis methods, the catalysts supported on alumina and ceria show the best performance. This could be explained by the higher surface area of the Ni NPs on the alumina surface and presence of oxygen vacancies in the CeO₂ lattice, which favor the proportion of oxygen adsorbed on defect sites. The catalysts supported on MgO suffer quick deactivation due to formation of a NiO/MgO solid solution, which is not reducible under the reaction conditions. The low level of carbon formation over the catalysts supported on La₂O₃ is ascribed to the very high dispersion of the nickel NPs and to the formation of lanthanum oxycarbonate, through which carbon deposits are gasified. The catalytic behavior for catalysts with ZrO₂ as support depends on the synthesis method; however, in both cases, the catalysts undergo deactivation by carbon deposits.

A Cu-Doped ZIF-8 metal organic framework as a heterogeneous solid catalyst for aerobic oxidation of benzylic hydrocarbons

Cu(ii) ions doped into ZIF-8 MOFs are shown to activate C–H bonds in benzylic hydrocarbons to their corresponding alcohol/ketone products.

Combined Steam Reforming of Methane and Formic Acid To Produce Syngas with an Adjustable H2:CO Ratio

Syngas is an important intermediate in the chemical process industry. It is used for the production of hydrocarbons, acetic acid, oxo-alcohols, and other chemicals. Depending on the target product and stoichiometry of the reaction, an optimum (molar) ratio between hydrogen and carbon monoxide (H₂:CO) in the syngas is required. Different technologies are available to control the H₂:CO molar ratio in the syngas. The combination of steam reforming of methane (SRM) and the water-gas shift (WGS) reaction is the most established approach for syngas production. In this work, to adjust the H₂:CO ratio, we have considered formic acid (FA) as a source for both hydrogen and carbon monoxide. Using thermochemical equilibrium calculations, we show that the syngas composition can be controlled by cofeeding formic acid into the SRM process. The H₂:CO molar ratio can be adjusted to a value between one and three by adjusting the concentration of FA in the reaction feed. At steam reforming conditions, typically above 900 K, FA can decompose to water and carbon monoxide and/or to hydrogen and carbon dioxide. Our results show that cofeeding FA into the SRM process can adjust the H₂:CO molar ratio in a single step. This can potentially be an alternative to the WGS process.

Ruthenium oxide modified nickel electrode for ascorbic acid detection

Electrodes of ruthenium oxide modified nickel were prepared by a thermal decomposition method. The stoichiometry of the modifier, RuO_x, was quantitatively determined to be a meta-stable phase, RuO₅. The electrodes were employed to sense ascorbic acid in alkaline solution with a high sensitivity, 296 μAcm^-2 mM^-1, and good selectivity for eight kinds of disturbing reagents. We found that the ascorbic acid was oxidized irreversibly in solution. To match with the variation of the morphology, the sensitivity reached a maximum when the RuO_x segregated with a nano-crystalline feature. We find that the substrate oxidized as the deposited RuO_x grew thicker. The feature of the deposited RuO_x changed from nano-particles to small islands resulting from the wetting effect of the substrate oxide, NiO; meanwhile the sensitivity decreased dramatically. The endurance of the RuO_x/Ni electrode also showed a good performance after 38 days of successive test.

Investigation of Methane Oxidation Reactions Over a Dual-Bed Catalyst System using 18 O Labelled DRIFTS coupling

Low loading Pd-supported (0.2 wt % Pd) Y-stabilized zirconia (YSZ) and LaMnO₃ (LM) perovskite were associated to study the partial oxidation of methane using labelled ¹⁸ O₂ in the gas phase. Synthesis gas production was demonstrated to occur through an indirect reaction in which oxygen is first consumed in the total methane combustion. A Mars-van Krevelen mechanism was observed over Pd/YSZ at 425 °C to yield C¹⁶ O₂ and C¹⁶ O. A significant enhancement of the Pd/YSZ catalyst activity was achieved by the association of LM-Pd/YSZ in a dual catalyst bed, resulting in a significant increase of the oxidation rate. Vibration bands of adsorbed formate species, assumed to be intermediates to the gas production, were observed by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) coupling experiments. It was proposed that LM enables the generation of highly active singlet O₂ , which is activated on the YSZ oxygen vacancies to assist a rapid recovery of surface PdO and increase formate decomposition into CO and H₂ in Pd-supported catalyst.

Hydrogen-Permeable Tubular Membrane Reactor: Promoting Conversion and Product Selectivity for Non-Oxidative Activation of Methane over an Fe©SiO2 Catalyst

Non-oxidative methane conversion over Fe©SiO₂ catalyst was studied for the first time in a hydrogen (H₂ ) permeable tubular membrane reactor. The membrane reactor is composed of a mixed ionic-electronic SrCe_0.7 Zr_0.2 Eu_0.1 O_3-δ thin film (≈20 μm) supported on the outer surface of a one-end capped porous SrCe_0.8 Zr_0.2 O_3-δ tube. Significant improvement in CH₄ conversion was achieved upon H₂ removal from the membrane reactor compared to that in a fixed-bed reactor. The Fe©SiO₂ catalyst in the H₂ permeable membrane reactor demonstrated a stable ≈30 % C₂₊ single-pass yield, with up to 30 % CH₄ conversion and 99 % selectivity to C₂ (ethylene and acetylene) and aromatic (benzene and naphthalene) products, at the tested conditions. The selectivity towards C₂ or aromatics was manipulated purposely by adding H₂ into or removing H₂ from the membrane reactor feed and permeate gas streams.

Strategies for Carbon and Sulfur Tolerant Solid Oxide Fuel Cell Materials, Incorporating Lessons from Heterogeneous Catalysis

Solid oxide fuel cells (SOFCs) are a rapidly emerging energy technology for a low carbon world, providing high efficiency, potential to use carbonaceous fuels, and compatibility with carbon capture and storage. However, current state-of-the-art materials have low tolerance to sulfur, a common contaminant of many fuels, and are vulnerable to deactivation due to carbon deposition when using carbon-containing compounds. In this review, we first study the theoretical basis behind carbon and sulfur poisoning, before examining the strategies toward carbon and sulfur tolerance used so far in the SOFC literature. We then study the more extensive relevant heterogeneous catalysis literature for strategies and materials which could be incorporated into carbon and sulfur tolerant fuel cells.

Computational, electrochemical, and spectroscopic studies of two mononuclear cobaloximes: the influence of an axial pyridine and solvent on the redox behaviour and evidence for pyridine coordination to cobalt(i) and cobalt(ii) metal centres

[Co(dmgBF2)2(H2O)2] (where dmgBF2 = difluoroboryldimethylglyoximato) was used to synthesize [Co(dmgBF2)2(H2O)(py)]·0.5(CH3)2CO (where py = pyridine) in acetone. The formulation of complex was confirmed by elemental analysis, high resolution MS, and various spectroscopic techniques. The complex [Co(dmgBF2)2(solv)(py)] (where solv = solvent) was readily formed in situ upon the addition of pyridine to complex . A spectrophotometric titration involving complex and pyridine proved the formation of such a species, with formation constants, log K = 5.5, 5.1, 5.0, 4.4, and 3.1 in 2-butanone, dichloromethane, acetone, 1,2-difluorobenzene/acetone (4 : 1, v/v), and acetonitrile, respectively, at 20 °C. In strongly coordinating solvents, such as acetonitrile, the lower magnitude of K along with cyclic voltammetry, NMR, and UV-visible spectroscopic measurements indicated extensive dissociation of the axial pyridine. In strongly coordinating solvents, [Co(dmgBF2)2(solv)(py)] can only be distinguished from [Co(dmgBF2)2(solv)2] upon addition of an excess of pyridine, however, in weakly coordinating solvents the distinctions were apparent without the need for excess pyridine. The coordination of pyridine to the cobalt(ii) centre diminished the peak current at the Epc value of the Co(I/0) redox couple, which was indicative of the relative position of the reaction equilibrium. Herein we report the first experimental and theoretical (59)Co NMR spectroscopic data for the formation of Co(i) species of reduced cobaloximes in the presence and absence of py (and its derivatives) in CD3CN. From spectroelectrochemical studies, it was found that pyridine coordination to a cobalt(i) metal centre is more favourable than coordination to a cobalt(ii) metal centre as evident by the larger formation constant, log K = 4.6 versus 3.1, respectively, in acetonitrile at 20 °C. The electrosynthesis of hydrogen by complexes and in various solvents demonstrated the dramatic effects of the axial ligand and the solvent on the turnover number of the respective catalyst.

Joint Analysis of Radiative and Non-Radiative Electronic Relaxation Upon X-ray Irradiation of Transition Metal Aqueous Solutions

L-edge soft X-ray spectroscopy has been proven to be a powerful tool to unravel the peculiarities of electronic structure of transition metal compounds in solution. However, the X-ray absorption spectrum is often probed in the total or partial fluorescence yield modes, what leads to inherent distortions with respect to the true transmission spectrum. In the present work, we combine photon- and electron-yield experimental techniques with multi-reference first principles calculations. Exemplified for the prototypical FeCl2 aqueous solution we demonstrate that the partial yield arising from the Fe3s → 2p relaxation is a more reliable probe of the absorption spectrum than the Fe3d → 2p one. For the bonding-relevant 3d → 2p channel we further provide the basis for the joint analysis of resonant photoelectron and inelastic X-ray scattering spectra. Establishing the common energy reference allows to assign both spectra using the complementary information provided through electron-out and photon-out events.

A bifunctional solid oxide electrolysis cell for simultaneous CO2 utilization and synthesis gas production

Herein, we report a pioneering solid oxide cell which consumes CO₂ to produce CO at the cathode side and simultaneously synthesizes valuable syngas at the anode side via a one-step green process.

Controlling the crystallisation of oxide materials by solvothermal chemistry: tuning composition, substitution and morphology of functional solids

Three aspects in the synthesis of oxides under solvothermal conditions are reviewed: materials discovery, substitutional chemistry and crystal habit control.

Ba4Ru3O10.2(OH)1.8: a new member of the layered hexagonal perovskite family crystallised from water

Two chemical reagents in water at 200 °C yield a complex barium ruthenate with a new 8H perovskite stacking sequence.

A review of dry (CO2) reforming of methane over noble metal catalysts

Dry (CO2) reforming of methane (DRM) is a well-studied reaction that is of both scientific and industrial importance. This reaction produces syngas that can be used to produce a wide range of products, such as higher alkanes and oxygenates by means of Fischer-Tropsch synthesis. DRM is inevitably accompanied by deactivation due to carbon deposition. DRM is also a highly endothermic reaction and requires operating temperatures of 800-1000 °C to attain high equilibrium conversion of CH4 and CO2 to H2 and CO and to minimize the thermodynamic driving force for carbon deposition. The most widely used catalysts for DRM are based on Ni. However, many of these catalysts undergo severe deactivation due to carbon deposition. Noble metals have also been studied and are typically found to be much more resistant to carbon deposition than Ni catalysts, but are generally uneconomical. Noble metals can also be used to promote the Ni catalysts in order to increase their resistance to deactivation. In order to design catalysts that minimize deactivation, it is necessary to understand the elementary steps involved in the activation and conversion of CH4 and CO2. This review will cover DRM literature for catalysts based on Rh, Ru, Pt, and Pd metals. This includes the effect of these noble metals on the kinetics, mechanism and deactivation of these catalysts.

Recent advances in the methanol synthesis via methane reforming processes

Depleting fossil fuel resources and continuously degrading environment due to greenhouse gases demands an immediate search for alternative clean energy resources to reduce the global warming associated problems.

Non-innocent adsorption of Co-pyrphyrin on rutile(110)

Co-pyrphyrin adsorbed on rutile(110) as a supported catalyst for water reduction.