Partial Oxidation Reactions Research Articles

One‐Step Synthesis of Melem‐Based Supramolecular Assemblies and Their Photocatalytic Properties

In this work, melem‐based supramolecular assemblies were obtained in one step by thermal treatment of melamine in an autoclave in the presence of sodium chloride. The detailed analysis showed that the obtained powder consists of two phases: poorly crystalline Na‐PHI flakes and rod‐shaped melem hydrate single crystals (several micrometers long and ~300‐500 nm wide). Melem hydrate crystals absorb light in the visible range (Eg = 2.7 eV) and demonstrate photocatalytic activity in the reaction of partial oxidation of benzyl alcohol to benzaldehyde by air under visible light with high selectivity for the target product. At 60% conversion of benzyl alcohol, the selectivity of benzaldehyde formation is above 95%.

Enhancing selectivity through forced dynamic operation with intraparticle diffusion limitations: Ethane oxidative dehydrogenation

During steady state operation (SSO) of industrial fixed-bed reactors diffusion limitations are often present. Well-known impacts include the reduced rate of a positive order reaction and reduced selectivity of the desired intermediate product in a sequential reaction system. This work presents an approach for circumventing diffusion limitations through forced dynamic operation (FDO) of metal oxide catalyzed partial oxidation reactions. Through coupled experiments and modeling, we examine the use of FDO to mitigate selectivity losses of the intermediate product in a parallel-consecutive reaction. With the oxidative dehydrogenation (ODH) of ethane (C2H6) to ethylene (C2H4) over an Al2O3 supported VOx catalyst as the model reaction system, FDO is shown to mitigate undesired C2H4 overoxidation to COx that predominates in steady state diffusion-limited pellets, resulting in C2H4 selectivities that are 15 % (absolute) higher compared to SSO in 2.6 mm catalyst pellets. A kinetic model reveals that FDO beneficially alters the distribution of chemisorbed (O*) and lattice (OL) oxygen, which respectively primarily participate in reactions consuming C2H4 and C2H6. FDO is shown to lead to less detrimental impact of diffusion on the ethylene selectivity and yield compared to SSO. During FDO, generated C2H4 reacts with unselective O*, leaving behind selective OL. The reduced bulk phase O2 in the reductive half cycle leads to accumulation of OL, suppressing C2H4 overoxidation. This effect is amplified via C2H4 trapping in the catalyst pellet. Thus, larger catalyst pellets exhibit selectivities that more rapidly increase with reduction time, inducing higher FDO cycle averages compared to SSO. The findings raise the prospect of applying FDO through feed switching or chemical looping as a way to increase intermediate yield in the class of partial oxidation reactions.

Inhibiting the Formation of Toxic HCN Induced by C3H6 Coexistence and Enhancing C3H6 Resistance of Cu-Zeolite in the NH3-SCR Reaction.

The presence of light hydrocarbons (HCs) in diesel exhaust, specifically C3H6, significantly affects the performance of the state-of-the-art Cu-SSZ-13 zeolite NH3-SCR catalysts. It also leads to the formation of highly toxic HCN, posing risks to the environment and human health. In this work, the highly toxic HCN formation is inhibited, and the C3H6 resistance of Cu-SSZ-13 is improved by secondary metal modification via doping with rare earth/transition metal elements. Upon introduction of C3H6, the activity of Cu-SSZ-13 significantly decreases at medium-high temperatures. This is primarily due to the competitive reaction between C3H6 and NH3, which compete for the NH3 reductant required in the NH3-SCR reaction, resulting in the production of HCN. The unfavorable effect is alleviated on the modified catalysts due to their enhanced oxidation capabilities toward C3H6 and the HCHO intermediate, facilitating the complete oxidation of C3H6 to COx. This inhibits the undesirable partial oxidation reaction between C3H6 and NH3, thereby improving the activity of Cu-SSZ-13 at medium to high temperatures and significantly reducing the formation of highly toxic HCN.

Quantitative localisation of titanium in the framework of titanium silicalite-1 using anomalous X-ray powder diffraction

One of the biggest obstacles to developing better zeolite-based catalysts is the lack of methods for quantitatively locating light heteroatoms on the T-sites in zeolites. Titanium silicalite-1 (TS-1) is a Ti-bearing zeolite-type catalyst commonly used in partial oxidation reactions with H2O2, such as aromatic hydroxylation and olefin epoxidation. The reaction mechanism is controlled by the configuration of titanium sites replacing silicon in the zeolite framework, but these sites remain unknown, hindering a fundamental understanding of the reaction. This study quantitatively determines heteroatoms within the zeolite-type framework using anomalous X-ray powder diffraction (AXRD) and the changes in the titanium X-ray scattering factor near the Ti K-edge (4.96 keV). Two TS-1 samples, each with approximately 2 Ti atoms per unit cell, were examined. Half of the titanium atoms are primarily split between sites T3 and T9, with the remainder dispersed among various T-sites within both MFI-type frameworks. One structure showed significant non-framework titanium in the micropores of a more distorted lattice. In both samples, isolated titanium atoms were more prevalent than dinuclear species, which could only potentially arise at site T9, but with a significant energy penalty and were not detected.

Spectroscopic Characterization of Ti Sites in MWW Zeolite in Presence of Hydrogen Peroxide

AbstractTi‐MWW zeolite is a promising catalyst for partial oxidation reactions. In the present work, a Ti‐MWW sample with high TiO2 loading was synthesized. It was revealed that the Ti insertion in the purely siliceous MWW framework mainly occurs during the post treatment washing with HNO3, when the double structure directing agent synthetic method is used. By exploiting carbon monoxide, acetonitrile, pyridine and ammonia as probe molecules in infrared spectroscopy and diffuse reflectance ultraviolet spectroscopy, the acidic behavior of the Ti sites and the interaction of the Ti sites with hydrogen peroxide (H2O2) were revealed. The Ti Lewis acid sites showed stronger acidity than the one observed in Titanium Silicalite‐1 (TS‐1), with MFI framework. This is coherent with previously reported results, suggesting that a significative fraction of the Ti sites in Ti‐MWW are TiOH(SiO)3 instead of Ti(OSi)4. The Ti‐peroxo and ‐hydroperoxo complexes formed upon H2O2 were shown to be more labile than in TS‐1 and they were shown to be completely reversible upon calcination.

Tuning Ce-doping La0.7Sr0.3Fe0.9Ni0.1O3-δ internal reforming catalyst to enhanced conversion efficiency and coking tolerance of solid oxide fuel cells fueled by oxygen-bearing low concentration coal mine methane

Solid oxide fuel cells (SOFCs) possess the potential to directly utilize abundant low concentration coal mine methane for power generation, which is crucial for energy conservation and reducing greenhouse gas emissions. Herein, Ce-doped La0.55Ce0.15Sr0.3Fe0.9Ni0.1O3-δ (LCSFN) perovskite is firstly employed as an anode internal reforming catalyst to enhance the electrochemical performance, stability, and resistance against carbon deposition in SOFCs. The results demonstrate that Ni-Fe alloy nanoparticles can be effectively precipitated from LCSFN under reducing atmosphere, thereby significantly promoting the partial oxidation reaction of methane while preventing direct contact between methane and Ni particles for the anode. The anode-supported single cells demonstrated exceptional electrochemical performance using a composite catalytic layer consisting of LCSFN-Ce0.9Gd0.1O2-δ (LCSFN-GDC). At 800℃, the utilization of both H2 and 16 %CH4-1 %O2-N2 resulted in the attainment of maximum power densities (MPD) measuring 881.66 mW·cm−2 and 824.69 mW·cm−2, respectively, with the recorded values for polarization resistance were 0.32 and 1.16 Ω·cm2. Additionally, the single cells equipped with LCSFN-GDC internal reforming catalytic exhibit remarkable resistance to carbon deposition, maintaining stable performance for a duration of 100 h using 16 %CH4-1 %O2-N2. These findings underscore the efficacy of methane catalysts in SOFCs, as it not only enhances power generation efficiency through using internal reforming catalyst but also ensures long-term stability by mitigating carbon-related issues.

Manganese-rhodium nanoparticles: Adsorption on titanium oxide surfaces and catalyst for syngas reactions.

Manganese-rhodium (Mn-Rh) nanoparticles have emerged as a promising candidate for catalytic applications in the production of syngas, a critical precursor for a wide range of industrial processes. This study employs a comprehensive, theoretical, and computational approach to investigate the structural and electronic properties of Mn-Rh nanoparticles, with a specific focus on their interaction with titanium oxide (TiO2) surfaces and their potential as catalysts for syngas reactions. The density functional theory calculations are employed to explore the adsorption behavior of Mn-Rh nanoparticles on TiO2 surfaces. By analyzing the adsorption energies, geometries, and electronic structure at the nanoscale interface, we provide valuable insights into the stability and reactivity of Mn-Rh nanoparticles when immobilized on TiO2 supports. Furthermore, the catalytic performance of Mn-Rh nanoparticles in syngas production is thoroughly examined. Through detailed reaction mechanism studies and kinetic analysis, we elucidate the role of Mn and Rh in promoting syngas generation via carbon dioxide reforming and partial oxidation reactions. The findings demonstrate the potential of Mn-Rh nanoparticles as efficient catalysts for these crucial syngas reactions. This research work not only enhances our understanding of the fundamental properties of Mn-Rh nanoparticles but also highlights their application as catalysts for sustainable and industrially significant syngas production.

Effect of O2/n-C5H12 Ratio on Oxygenates Production from Plasma N-pentane Partial Oxidation

Objective: Non-thermal plasma is a promising method for producing clean fuels. This work provides a deeper understanding of the impact of O2/n-C5H12 ratio on the partial oxidation of n-pentane from both physical and chemical perspectives. Moreover, this work offers insight into improving fuel combustion efficiency and technical support for the preparation of clean fuels. Methods: An experimental system based on dielectric barrier discharge plasma was established. The discharge characteristics and product generation status of n-pentane partial oxidation were measured by changing the concentration of oxygen and n-pentane to evaluate different O2/n-C5H12 ratios. Results: Research on discharge characteristics showed that the O2/n-C5H12 ratio did not affect the discharge mode, and typical Lissajous shapes were present at different ratios. Changing the O2/n-C5H12 ratio affected the oxygen concentration, average electron energy or electron density, and background temperature. As the O2/n-C5H12 ratio increased, the conversion of the n-pentane partial oxidation reaction increased. However, changing the O2/n-C5H12 ratio did not affect the type of generated products. The oxygenates exhibited a volcano curve, and an O2/n-C5H12 ratio of 1.00 achieved the highest selectivity of 35.1%. As the O2/n-C5H12 ratio continued to increase, the selectivity of oxygenates decreased and the selectivity of CO2 increased. This was potentially due to a shift from partial oxidation toward complete oxidation, which led to the generation of secondary pollutants. Thus, higher O2/n-C5H12 ratios were not conducive to clean fuel production and environmental friendliness. Conclusion: In the partial oxidation of n-pentane, the highest clean fuel production rate was achieved when the O2/n-C5H12 ratio was 1.00. When this ratio exceeded 1.00, the reaction shifted toward complete oxidation, producing secondary pollutants. This study provides ideas for improving fuel combustion efficiency and technical support for the preparation of clean fuels.

Tailored SrFeO3-δ for chemical looping dry reforming of methane

Chemical looping dry reforming of methane (CL-DRM) is a highly efficient process that converts two major greenhouse gases (CH4 and CO2) into syngas ready for the feedstock of liquid fuel production. One of the major obstacles facing this technology now is creating oxygen carriers that are stable and reactive. We fabricated high-performance Sr0.98Fe0.7Co0.3O3-δ perovskite-structured oxygen carrier by combining A-site defects and B-site doping of SrFeO3-δ. During isothermal CL-DRM tests at 850 °C, Sr0.98Fe0.7Co0.3O3-δ achieved 87% CH4 conversion and 94% CO selectivity in the CH4 partial oxidation reaction, followed by a syngas yield of 8.5 mmol/g, and CO yield of 4.2 mmol/g in CO2 decomposition. A-site defect engineering of the perovskite creates abundant oxygen vacancies and enhances oxygen storage capacity (OSC). Co-doping of the B-site of Sr0.98FeO3-δ increases oxygen mobility and CH4/CO2 activation, resulting in high activity in the CL-DRM process. This methodology resulted in high ionic mobility and facilitated the rapid diffusion of oxygen in the bulk phase, thereby increasing the redox properties of SrFeO3-δ. The oxygen carrier exhibits excellent structural stability and regeneration ability in successive redox cycles. This strategy offers a simple but very effective pathway to tailor OSC, oxygen mobility, and oxygen vacancies of perovskite-structured materials for chemical looping or redox-involved processes.

Upscaling Thermoelectrics: Micron-Thick, Half-a-Meter-Long Carbon Nanotube Films with Monolithic Integration of p- and n-Legs.

In order for organic thermoelectrics to successfully establish their own niche as energy-harvesting materials, they must reach several crucial milestones, including high performance, long-term stability, and scalability. Performance and stability are currently being actively studied, whereas demonstrations of large-scale compatibility are far more limited and for carbon nanotubes (CNTs) are still missing. The scalability challenge includes material-related economic considerations as well as the availability of fast deposition methods that produce large-scale films that simultaneously satisfy the thickness constraints required for thermoelectric modules. Here we report on true solutions of CNTs that form gels upon air exposure, which can then be dried into micron-thick films. The CNT ink can be extruded using a slot-shaped nozzle into a continuous film (more than half a meter in the present paper) and patterned into alternating n- and p-type components, which are then folded to obtain the finished thermoelectric module. Starting from a given n-type film, differentiation between the n and p components is achieved by a simple postprocessing step that involves a partial oxidation reaction and neutralization of the dopant. The presented method allows the thermoelectric legs to seamlessly interconnect along the continuous film, thus avoiding the need for metal electrodes, and, most importantly, it is compatible with large-scale printing processes. The resulting thermoelectric legs retain 80% of their power factor after 100 days in air and about 30% after 300 days. Using the proposed methodology, we fabricate two thermoelectric modules of 4 and 10 legs that can produce maximum power outputs of 1 and 2.4 μW, respectively, at a temperature difference ΔT of 46 K.

Experimental investigation of integrated CO2 capture and conversion to syngas via calcium looping coupled with dry reforming of CH4

Calcium looping integrated with dry reforming of CH4 is a promising strategy for CO2 capture and in situ conversion to syngas. This intensified process is usually conducted with bifunctional materials that combine CO2 capture (CaO) and catalytic (Ni) active sites. Herein, the integrated calcium looping/dry reforming process was examined by investigating various bifunctional materials and operating conditions. The Ni loading of materials affected the interaction between active and inert phases, while adding a CaZrO3 promoter enhanced the CO2 capture and catalytic activities and the resistance toward sintering. Conducting experiments with a fluidized bed reactor (700 °C, 3% CH4 in feed) led to nearly complete CH4 conversion and ∼52% utilization of captured CO2 toward syngas production with steady H2/CO ratio close to unity. Temperature comprised a decisive parameter, with low values enabling high degrees of CO2 conversion up to ∼80%. The increase of CH4 concentration in the gas feedstock enhanced the rate of calcination and the conversion of CO2 over its desorption in the gas phase. Co-feeding O2 with CH4 was proposed to mitigate the energy demand, which reduced the reforming selectivity for the partial oxidation reaction and increased the H2/CO ratio of syngas.

Mesoporous configuration effects on the physicochemical features of hierarchical ZSM-5 supported cobalt oxide as catalysts in methane partial oxidation

Hierarchical porous system has become a prevalent method to overcome the diffusion limitation of conventional zeolites. Two types of mesopores characterized as intra-crystalline (mesopores in the zeolite pore wall) and inter-crystalline mesopores (meso-sized voids between nano-zeolite aggregates) could be formed in the synthesis of hierarchical zeolites. In an attempt to investigate the influence of mesopores structure on the physicochemical properties of hierarchical ZSM-5, specifically cobalt oxide impregnated ZSM-5 zeolite samples with intra- and inter-crystalline mesopores were synthesized through two different synthesis strategies. Analysis of the physicochemical properties of the as-modified hierarchical ZSM-5 catalysts were carried out using SEM, TEM, XPS, and H2-TPR which showed distinct features given by the two mesopores configurations. Co-oxide impregnated on ZSM-5 with inter-crystalline mesopores was dominated by Co(II) species, while Co-oxide/ZSM-5 showed a fair amount of Co(III) and Co(II). Furthermore, analysis of the catalytic activity was conducted using methane partial oxidation as a model reaction. With a variation in reaction time, various types of oxygenated products, i.e. methanol, formaldehyde, formic acid, and a small trace of carbon dioxide were observed. Catalytic results suggested that the Co-oxide/ZSM-5 material with inter-crystalline mesopores configuration is more active for the methane partial oxidation reaction compared to the Co-oxide/ZSM-5 with intracrystalline mesopores. This was confirmed by the formation of formaldehyde rather than methanol as the major product in the brief reaction time of 30 min.

Upcycling plastic waste into syngas by staged chemical looping gasification with modified Fe-based oxygen carriers

A novel staged approach, termed staged chemical looping gasification (SCLG) was proposed in this work, for the efficient upcycling of plastic waste into H2-rich syngas with exceptional carbon conversion reaching up to 99%. In such staged system, plastic was firstly pyrolyzed to generate hydrocarbon volatiles, followed by chemical looping reforming in the presence of oxygen carriers, and steam and air was also feed in sequence for carbon removal, syngas regulation and lattice oxygen recovery. A series of Fe-M-Al oxygen carriers (OCs, where M represents Mg, Ca, Mn, Mo, La, Ce) were synthesized and employed for SCLG of waste disposable masks. The performance and stability of these OCs were thoroughly investigated and compared in terms of H2 content and syngas production, while the physicochemical properties characterized by various techniques such as N2 isothermal adsorption-desorption, FESEM, XRD, TPO, and H2-TPR. Results showed that compared with the controlled FeAl sample, all the six modified OCs exhibited higher activity towards syngas production, due to the simultaneously enhanced both partial oxidation reactions and thermal decomposition reactions during the proposed SCLG process. However, the modifiers displayed different role for promoting gasification. Specifically, the addition of Ca significantly promoted the thermal cracking of plastic pyrolysis volatiles and lead to the deep extraction of carbon and H2, whereas the deposited carbon was further gasified into syngas in steam stage. As a result, Fe-Ca-Al showed the highest syngas yield and carbon conversion of 177.89 mmol/gOC and 99.03%, respectively. Fe-Mg-Al possessed relatively high CO selectivity, with the CO/(CO + CO2) ratio of 90.40%. The presence of MoO3 made the Fe-Mo-Al equipped with strong oxygen supply ability, leading to high content of oxygen-containing gases. Furthermore, the cycle stability of OCs was also conducted. The slight decrease in activity of Fe-Ca-Al was due to the metal sintering, whereas Fe-Mo-Al presented relatively stable syngas yield. The proposed staged chemical looping gasification with modified FeAl was demonstrated as a promising upcycling utilization of disposal plastic waste.

Partial Methane Oxidation to Methanol on Ru-Porphyrins - on the Role of Non-Innocent Ligands and Spin Crossover.

The partial oxidation reaction of CH4 led to the formation of CH3 OH in the presence of Ru-porphyrin oxo complexes (denoted as POR, POR-O and POR-OH where in the case of the last two, oxygen atom and the OH group were attached to the active site, respectively), in which Ru was present on different oxidation states. The simulations were performed based on Density Functional Theory (DFT) with extended geometric and electronic structure analyses of each reaction step. Moreover, the reaction pathways were investigated in different spin states. The Spin Crossover (SCO) phenomenon was found to play an important role in the kinetics of the reaction in the presence of POR and POR-O. Harmonic Oscillator Model of Aromaticity (HOMA) index was applied for different spin states to estimate the aromaticity changes of the pyrrole rings in the Ru-porphyrin complexes. In order to characterize the nature of bonding, the Natural Bond Orbitals (NBO) analysis including the Wiberg Bond Index (WBI) and Natural Population Analysis (NPA) was carried out. Finally, the Non-Covalent Interactions (NCI) index was employed to gain insight into interactions between the components of the reaction. It was found that the non-covalent interactions cannot be neglected in the studied reaction paths.

Oxygen vacancies enriched Ni-Co/SiO2@CeO2 redox catalyst for cycling methane partial oxidation and CO2 splitting

Redox catalysts play a vital role in the interconversion of two significant greenhouse gases, CO2 and CH4, via chemical looping methane dry reforming technology. Herein, a series of transition metals-alloyed and core–shell structured Ni-M/SiO2@CeO2 (M = Fe, Co, Cu, Mn, Zr) redox catalyst were fabricated and evaluated in a gas–solid fixed-bed reactor for cycling CH4 partial oxidation (POx) and CO2 splitting. The catalysts are composed of spherical SiO2 core and CeO2 shell, and the highly dispersed Ni alloy nanoparticles are the interlayer between core and shell. The oxygen vacancy concentration of Ni-M/SiO2@CeO2 followed the order of Co > Cu > Fe > Mn > Zr, and Ni alloying with transition metals significantly enhanced oxygen storage capacity (OSC). Ni-Co/SiO2@CeO2 catalyst with abundant oxygen vacancies and a high OSC showed the lowest temperatures of CH4 activation (610 °C) and CO2 decomposition (590 °C), thus demonstrating excellent redox reactivity. The catalyst exhibited superior activity and structural stability in the continuous CH4/CO2 redox cycles at 615 °C, achieving 87% CH4 conversion and 83% CO selectivity. The proposed catalyst shows great potential for the utilization of CH4 and CO2 in a redox mode, providing a new sight for design redox catalyst in chemical looping or related fields.

Optimal integration modeling of Co – Electrolysis in a power-to-liquid industrial process

High temperature co-electrolysis using solid-oxide electrolysis cells is a highly efficient pathway for green syngas production owing to the possibility of heat integration with other processes. Therefore, this study described and evaluates a flexible and efficient configuration for producing sustainable synthetic fuels using electricity from renewables and captured CO2 by integrating co-electrolysis in a power-to-liquid industrial plant. Thereafter, novel and efficient technologies were implemented for green syngas production and its subsequent purification, increasing the overall process efficiency and achieving a significant reduction in the carbon footprint compared to mature synthetic crude production processes. Catalytic partial oxidation and dual pressure swing adsorption were integrated with co-electrolysis and Fischer–Tropsch synthesis in a scaled industrial plant, using residual streams from the complex or those of renewable origin as feed, which allowed the continuous operation of the process independent of renewable power generation. The mass and energy balance, performance, and efficiency estimations were also included in this study. A solid-oxide electrolytic cell (SOEC) plant using renewable electricity and heat input from thermal integration with the outlet syngas stream of the catalytic partial oxidation reactor was selected as a case study. Both the performance and efficiency analyses of the co-electrolysis unit demonstrated the benefits of such thermal integration in comparison with current solutions. In this study, both the thermal integration of the process streams, as well as the energy and heat consumed by the syngas purification process were considered.

Carbon-supported VPO catalysts with fibrous structure: A new family of catalysts for partial oxidation reactions

The present contribution describes the synthesis of a carbon supported VPO catalyst with a fibrous structure. The synthesis method is simple, low-cost, scalable and reproducible that allows the formation of the bulk mixed oxide (VO)2P2O7 (VPP) active phase on the carbon support material. The preparation does not require any special reducing thermal treatments due to the ability of the carbon support to stabilize the VPP active phase since this carbon-based support is stable under oxidizing conditions up to around 400ºC allowing it to be used as for catalytic oxidation reactions. The stability of the carbon-supported VPP catalyst under reaction conditions was examined with in situ Raman under oxidizing/ H2 reducing cycles and n-butane oxidation conditions under both wet and dry conditions. These studies confirm the dynamic character of VPO phases, which interconvert under different conditions, and the stability of carbon-supported VPP phase under different environments. The novel carbon-supported catalyst exhibits an activity behavior like that observed for commercial catalysts that suggests a very promising catalytic material.

Mild Methane Electrochemical Oxidation Boosted via Plasma Pre-Activation.

Obtaining partial methane oxidation reaction (MOR) with various oxygenates via a mild electrochemical method is practically difficult because of activation of stable C─H bond and consequent reaction pathway regulation. Here, a real-time tandem MOR with cascaded plasma and electrocatalysis to activate and convert the methane (CH4 ) synergistically is reported for the first time. Boosted CH4 conversion is demonstrated toward value-added products including, alcohols, carboxylates, and ketone via use of commercial Pd-based electrocatalysts. Compared with hash industrial processes, a mild condition, that is, anode potential < 1.0V versus RHE (reversible hydrogen electrode) is used that mitigates overoxidation of oxygenates and obviates competing reaction(s). One evidence that Pd(II) sites and surface adsorbed hydroxyls are important in facilitating activated-CH4 species conversion, and establish a reaction mechanism for conversion(s) that involves coupling reactions between adsorbed hydroxyls, carbon monoxide and C1 /C2 alkyls. One conclude that pre-activation is important in boosting electrochemical partial MOR under mild conditions and will be of benefit in the development of sustainable CH4 conversion technology.

Oxidative pyrolysis of plywood waste: Effect of oxygen concentration and other parameters on product yield and composition

Introducing a small amount of oxygen into the inert carrier gas will not only cause partial oxidation reaction, but also significantly change the composition and distribution of biomass pyrolysis products. The oxygen concentration greatly affects the balance between oxidation reaction and pyrolysis reaction. Therefore, it is very important to clarify the influence of oxygen concentration and other reaction conditions on oxidative pyrolysis. The results showed that the pyrolysis products yields remain constant when the oxygen concentration in the carrier gas ranges from 0 to 3 vol%; however, between 3 to 10 vol%, oxygen reacts with biochar to generate non-condensable gas and release heat, and the mass yield of bio-oil slightly declines. Compared with N2 atmosphere, the temperature corresponding to the maximum weight loss peak of pyrolysis under 10 vol% oxygen concentration shifts from 352.5 °C to 292.1 °C. With 10 vol% oxygen in the carrier gas, most of the oxygen transfers to non-condensable gas (6.8 vol%) and water (3.2 vol%). The proportion of 0–140 Da (acids, ketones, furans, BTX) in bio-oil decreases significantly. The biochar more porous structure and oxygen-containing functional groups. The study revealed the complex interactions among various parameters in oxidative pyrolysis.

Development of Membrane Reactor Coupling Hydrogen and Syngas Production.

Simultaneous syngas and pure hydrogen production through partial oxidation of methane and water splitting, respectively, were demonstrated by using mixed ionic-electronic conductors. Tubular ceramic membranes prepared from La0.5Sr0.5FeO3 perovskite were successfully utilized in a 10 M lab scale reactor by applying a radial arrangement. The supply of methane to the middle area of the reaction zone was shown to provide a uniform distribution of the chemical load along the tubes' length. A steady flow of steam feeding the inner part of the membranes was used as oxidative media. A described configuration was found to be favorable to maintaining oxygen permeability values exceeding 1.1 mL∙cm-2∙min-1 and long-term stability of related functional characteristics. Methane's partial oxidation reaction assisted by 10%Ni@Al2O3 catalyst proceeded with selectivity values above 90% and conversion of almost 100%. The transition from a laboratory model of a reactor operating on one tubular membrane to a ten-tube one resulted in no losses in the specific performance. The optimized supply of gaseous fuel opens up the possibility of scaling up the reaction zone and creating a promising prototype of a multitubular reaction zone with a simplified sealing procedure.