Catalyst Mass Research Articles

Interfacial microenvironment to construct a three-dimensional fluoride-modified cobalt oxyhydroxide/polyvinylidene fluoride for the PMS activation to remove antibiotics

The monolithic membrane reactor for purification of antibiotics-contained wastewater offers a bright means to vanquish technological challenges associated with catalyst recovery, reaction efficiency, and mass transfer typically encountered in powdered heterogeneous catalysts. Herein, a fluoride-modified cobalt oxyhydrooxide (FCO) is planted on polyvinylidene fluoride (PVDF) film via constructing a microenvironment of Co2+-F- interaction. This optimized monolithic PVDF-supported FCO (FCO-PVDF) can completely remove tetracycline, ciprofloxacin and sulfadiazine via the peroxy-monosulfate (PMS) activation within 6 min. Additionally, the FCO-PVDF maintains outstanding resistance to environmental interference and high activity stability without decay after 8 consecutive cycles. Our investigations reveal that such exceptional performance stems from the exposure of cobalt-contained active sites for PMS activation and enhanced mass transfer in 3-D structure, leading to efficient generation of active species. Experiment and characterization demonstrate 1O2 active species play the most crucial role in eliminating antibiotics, in which perform PMS decomposition at a cobalt-exposed interface of FCO-PVDF. This work underscores the significance of designing PVDF membrane integrated fluoride-modified cobalt oxyhydroxide by constructing a unique interface microenvironment for PMS activation towards antibiotics removal.

Efficient Catalytic Reduction of Organic Pollutants Using Nanostructured CuO/TiO2 Catalysts: Synthesis, Characterization, and Reusability

The catalytic reduction of organic pollutants in water is a critical environmental challenge due to the persistent and hazardous nature of compounds like azo dyes and nitrophenols. In this study, we synthesized nanostructured CuO/TiO2 catalysts via a combustion technique, followed by calcination at 700 °C to achieve a rutile-phase TiO2 structure with varying copper loadings (5–40 wt.%). The catalysts were characterized using X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR–FTIR) spectroscopy, thermogravimetric analysis-differential thermal analysis (TGA–DTA), UV-visible diffuse reflectance spectroscopy (DRS), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDS). The XRD results confirmed the presence of the crystalline rutile phase in the CuO/TiO2 catalysts, with additional peaks indicating successful copper oxide loading onto TiO2. The FTIR spectra confirmed the presence of all the functional groups in the prepared samples. SEM images revealed irregularly shaped copper oxide and agglomerated TiO2 particles. The DRS results revealed improved optical properties and a decreased bandgap with increased Cu content, and 4-Nitrophenol (4-NP) and methyl orange (MO), which were chosen for their carcinogenic, mutagenic, and nonbiodegradable properties, were used as model organic pollutants. Catalytic activities were tested by reducing 4-NP and MO with sodium borohydride (NaBH4) in the presence of a CuO/TiO2 catalyst. Following the in situ reduction of CuO/TiO2, Cu (NPs)/TiO2 was formed, achieving 98% reduction of 4-NP in 480 s and 98% reduction of MO in 420 s. The effects of the NaBH4 concentration and catalyst mass were investigated. The catalysts exhibited high stability over 10 reuse cycles, maintaining over 96% efficiency for MO and 94% efficiency for 4-NP. These findings demonstrate the potential of nanostructured CuO/TiO2 catalysts for environmental remediation through efficient catalytic reduction of organic pollutants.

Free-Standing Carbon Nanofiber Films with Supported Cobalt Phosphide Nanoparticles as Cathodes for Hydrogen Evolution Reaction in a Microbial Electrolysis Cell.

High-performance and cost-efficient electrocatalysts and electrodes are needed to improve the hydrogen evolution reaction (HER) for the hydrogen (H2) generation in electrolysers, including microbial electrolysis cells (MECs). In this study, free-standing carbon nanofiber (CNF) films with supported cobalt phosphide nanoparticles have been prepared by means of an up-scalable electrospinning process followed by a thermal treatment under controlled conditions. The produced cobalt phosphide-supported CNF films show to be nanoporous (pore volume up to 0.33 cm3 g-1) with a high surface area (up to 502 m2 g-1) and with a suitable catalyst mass loading (up to 0.49 mg cm-2). Values of overpotential less than 140 mV at 10 mA cm-2 have been reached for the HER in alkaline media (1 M KOH), which demonstrates a high activity. The high electrical conductivity together with the mechanical stability of the free-standing CNF films allowed their direct use as cathodes in a MEC reactor, resulting in an exceptionally low voltage operation (0.75 V) with a current density demand of 5.4 A m-2. This enabled the production of H2 with an energy consumption below 30 kWh kg-1 H2, which is highly efficient.

Hydrodynamic and temperature profile analysis in a gas-solid fluidized bed with liquid atomization to convert fructose to value-added chemicals

Carbohydrates specified C6 sugars dehydrate to produce platform chemicals like 5-hydroxymethyl furfural and furfural that further oxidize to chemicals 2,5-diformyl furan and 2,5-furan dicarboxylic acid. Here we propose a gas-phase in which a two-fluid nozzle atomizes a 0:1 ▪ fructose in water solution into a fluidized bed of Mo–V–▪/▪. However, the imperfect interaction between droplet and catalyst increases the agglomeration, which destroys the heat transfer efficiency and hydrodynamic stability. We evaluated the temperature and gas residence time distribution in catalytic bed to improve reaction and process performance by modifying the bed temperature, bed height, and gas velocity. A high mass of catalyst (>▪) degrades fructose and reduces the selectivity. At ▪ temperature distributes homogeneously within bed and with time on process it shifts toward higher values. Velocity in the range of ▪ to ▪ yields product with the highest selectivity (16%). These results demonstrate the potential of optimizing gas-phase catalytic processes to improve the selective production of platform chemicals from carbohydrates, supporting more sustainable chemical manufacturing.

IL/MIL-101-NH2 heterogeneous catalyst prepared by acid-base self-assembly for hydrodeoxygenation of 2,5-tetrahydrofurandicarboxylic acid to adipic acid

Bio-based route for preparing adipic acid (AA) from 5-hydroxymethylfurfural is the direction for achieving green and sustainable AA production. In light of the challenges, such as corrosion and difficulties in recycling of I- containing homogeneous catalyst, large amount, high cost, and significant mass transfer resistance of ionic liquid (IL) catalyst, encountered in the current hydrodeoxygenation of 2,5-tetrahydrofurandicarboxylic acid (THFDCA) to AA process. Herein, 1-sulfobutyl-3-methylimidazolium iodide IL ([HSO3-b-mim]·I) was used to functionalize MIL-101-NH2 through acid-base self-assembly approach, hence, a heterogeneous catalyst, IL/MIL-101-NH2 was designed and applied in the hydrodeoxygenation of THFDCA to bio-based AA for the first time. When reacted at 180 °C for 2 h, the THFDCA conversion and AA yield were 100 % and 99.9 %, respectively. Moreover, IL/MIL-101-NH2 exhibited remarkable stability and could be reused multiple times with minimal loss in activity. XRD, SEM, FT-IR, BET, XPS, and TG results revealed that the functionalization process involved the reaction between HSO3 in the IL and NH2 in MIL-101-NH2, forming a salt that chemically bonded the IL to MIL-101-NH2, thereby enhancing stability. The excellent hydrodeoxygenation activity was attributed to the synergistic effect of the Lewis acid site (Cr3+) and the Lewis base nucleophilic site (I-) within IL/MIL-101-NH2.

Synthesis of graphitic carbon from empty palm oil fruit bunches through single-step graphitization process using K2FeO4-KOH catalyst as lithium ion battery anode

This research aims to optimize the graphitization process of carbon derived from Empty Palm Oil Fruit Bunches (EPOFB), a renewable biomass source, using a single-step K₂FeO₄-KOH impregnation-activation method. The results demonstrate that increasing the mass of K₂FeO₄, up to the optimal level, enhances the degree of graphitization, as confirmed by XRD and Raman spectroscopy. Optimal performance is observed with a catalyst mass of 0.11 g K₂FeO₄ in the C_ K₂FeO₄(0.11)KOH_800 sample, which exhibits a d002 spacing of 0.3356 nm, an IG/ID ratio of 2.42, a high surface area of 787.767 m²/g, and clearly defined graphitic layers in TEM images. Electrochemical testing of C_ K₂FeO₄(0.11)_KOH_800 reveals promising results, including the lowest charge transfer resistance (Rct) of 87.18 Ω, a significant area under the curve in cyclic voltammetry, a charging capacity of 330.3 mAh g⁻¹ at 0.1 C, with an excellent rate capability of 183 mAh g⁻¹ at 1 C after 100 cycles, maintaining a retention rate of 68.2 %. The single-step K₂FeO₄-KOH impregnation-activation method effectively enhances the graphitization of EPOFB-derived carbon, offering potential applications in high-performance lithium battery anodes.

Diameter controlled fabrication of ultralong silicon wires through regulating metal mass in massive metal-assisted chemical vapor deposition

Abstract The successful fabrication of ultra-long silicon wires has facilitated the study and application of silicon wires. However, research on the controlled fabrication of ultralong silicon wires, such as diameter modulation, is still insufficient. Herein, tapering ultralong silicon wires are synthesized by using a massive metal-assisted chemical vapor deposition method. By altering the mass of the tin catalyst in the growth zone, the length and changing rate of the diameter can be modulated. When a 40 g catalyst is placed in the growth region, the length of obtained silicon wires is 6.6 mm, and the changing rate of diameter with length is 541 nm/mm. When the catalyst mass in the growth region is reduced to 20 g, the length of the products decreases to 4.0 mm, and the changing rate of diameter with length increases to 964 nm/mm. This work proposes a new route for the diameter-modulated fabrication of ultralong silicon wires and will promote their application across various fields.

Modeling catalyst effectiveness factor with space-fractional derivative using Haar wavelet collocation method

Abstract Mass transfer limitations may considerably affect the rate of a heterogeneous catalytic process. The catalyst effectiveness factor is a quantitative measure of the impact of the diffusion process inside a catalyst particle. The effectiveness factor is derived from the solution of the steady-state reaction-diffusion problem. Herein, we simulate the steady-state reaction-diffusion equation with space-fractional derivative and linear reaction kinetics. The solution to the problem is obtained numerically using the Haar wavelet collocation method. The effect of the anomalous diffusion exponent on the catalyst effectiveness factor and process parameters, e.g. reactor volume and catalyst mass, is demonstrated. We anticipate that the process efficiency will be notably improved by changing the diffusion regime from standard to superdiffusive.

Understanding oxidation potential and degradation mechanism of acid-treated TiO2 coupled g-C3N4 S-scheme heterojunction photocatalyst for the removal of gaseous formaldehyde

In this work, a step (S)-scheme heterojunction catalyst is synthesized by coupling acid-treated TiO2 (ATT) with graphitic carbon nitride nanosheet (g-C3N4: GCN) and used for adsorption-photocatalytic removal of gaseous formaldehyde (FA: 100 - 500 ppm). The acid treatment of TiO2 proves to be an effective approach for improving the surface porosity of ATT with more abundant active sites for efficient catalytic reactions. Similarly, the S-scheme heterojunction displays superior redox potential (i.e., availability of free e- at conduction band of GCN (reduction potential of −0.485 eV/NHE) and free h+ at valance band of ATT (oxidation potential 2.79 eV/NHE)). As such, in a dynamic packed-bed flow reactor, the improved textural and optical properties of ATT-GCN (bed mass = 10 mg) offer outstanding adsorption and photocatalytic oxidation potential, effectively removing 86% of 200 ppm FA vapor at a reaction rate of 70.2 nmole mg−1 min−1 under slightly humidified conditions (e.g., 20% relative humidity (RH) and 21% O2) when exposed to 32-W UV-A light source. Under these operational conditions, the ATT-GCN achieves the superior performance metrics (e.g., quantum yield of 5.1E-02 molec. photon-1, space–time yield of 5.1E-03 molec. photon-1 mg−1, and specific clean air delivery rate of 515.4 L g-1 h−1). In-situ Kelvin probe microscope analysis of ATT-GCN postulates the formation of a strong built-in electric field to improve the separation of charge carriers. Considerations on the degradation pathway and intermediate dynamics with the aid of in-situ DRIFTS analysis suggest that the presence of water molecules (e.g., 20% RH) is beneficial for accelerating the oxidation and mineralization of FA molecules relative to a dry gas stream. The overall outcomes of this work are expected to help deliver new paths for the construction of advanced photocatalytic systems for upscaled applications toward air quality management.

Construction of Ag/AgCl@MIL-53(Fe): Achieving Efficient Photocatalytic Water Oxidation via the Plasma-Phase Silver and Heterojunction Synergistic Effect

The development of highly efficient water oxidation catalysts is a bottleneck in achieving artificial photosynthesis, as water oxidation is a complex process involving multiple electron and proton transfers. To further improve the photocatalytic water oxidation performance of MIL-53(Fe), a series of Ag/AgCl@MIL-53(Fe) samples with different Fe:Ag ratios were synthesized by hydrothermal methods and used in the photocatalytic water oxidation reactions. XRD characterization showed the successful preparation of Ag/AgCl@MIL-53(Fe) heterostructure catalysts. The reaction results showed that sample AAM-2 (Fe:Ag=5:1) had the best photocatalytic water oxidation performance, with the highest TOF value of 0.14 mmol/(g·s) and quantum efficiency of 39.0 % under the conditions of catalyst mass of 1 mg and pH=9.0 for boric acid-borax buffer solution. Measurements of photocurrent indicated that the AAM-2 samples doped with Ag/AgCl had higher photocurrent densities, thus improving the photocatalytic performance. This provides new insights for constructing highly efficient porous MOFs catalysts.

Effect of regenerated standpipe flow pattern on catalyst transport in fluid catalytic cracking unit

Standpipe is a pipeline that constitutes one of the components in the downstream portion of the catalyst circulation loop in a fluid catalytic cracking (FCC) unit, facilitates catalyst transportation between reactor and regenerator. This study measured pressures of the regenerated standpipe on a 1.0 Mt/a FCC unit to elucidate the underlying cause of the observed catalyst transportation. The results indicated that multiple flow patterns coexist within the standpipe, rather than a single dense-phase flow. The characteristic parameters of the static and dynamic pressure were intimately connected to the aforementioned flow patterns. The dynamic pressure data indicated that pressure dominant frequency and amplitude could employed in the identification of flow patterns. The packed bed flow had a pressure frequency ranging from 0 to 3.3 Hz, and a dominant frequency amplitude of 0.8, 1.8 and 2.2 Hz, allowed diagnosis of poor catalyst transport. The study demonstrated that the standpipe structure and catalyst mass flow rate were the key factors affecting gas-solid flow degassing by allowing for multiple flow patterns in the standpipe. The influence of aeration on the flow patterns was also discussed here, with an improper aeration rate resulting in reaction temperature fluctuations ranging from 0.5 to 23 °C.

Co3O4 coated carbon fiber activates PMS to degrade phenolic pollutants via 1O2 dominated non-radical pathway: Role of dual reaction center

Carbon fiber (CF) with a regular fiber skeleton structure was used to prepare the Co3O4@CF catalyst. The as-prepared catalyst was then applied to activate peroxymonosulfate (PMS) for the degradation of phenolic pollutants. Furthermore, the catalytic performance and degradation mechanisms are investigated in this study. The uniform dispersion of Co3O4 on the surface of the CF, as well as the presence of Co–O–R in the Co3O4@CF structure, was confirmed. Notably, 50 mg L−1 of bisphenol A (BPA) was completely degraded in the Co3O4@CF/PMS system within 20 min, under initial conditions of catalyst mass concentration at 0.2 g L−1, the PMS concentration at 10 mmol L−1, and a pH of 6.6. The total organic carbon removal rate reached 72.33 % over 90 min, indicating that the Co3O4@CF/PMS system exhibited strong mineralization capability for BPA. Furthermore, the catalyst demonstrated high efficiency in treating various types of refractory organic pollutants, showing promise for purifying coking wastewater from 3D-EEM. X-ray photoelectron spectroscopy and solid-state electron paramagnetic resonance revealed the formation of electron-poor and electron-rich centers in the Co3O4@CF structure. Density functional theory calculations further indicated that the charge density around the CF decreased, while the charge density around Co3O4 increased, resulting in the formation of these electron-poor and electron-rich centers. Electrochemical characterization using cyclic voltammetry and electrochemical impedance spectroscopy confirmed the excellent electron transfer rate of Co3O4@CF. Additionally, the reactive oxygen species dominated in the Co3O4@CF/PMS system were 1O2 and •O2−, with possible mechanisms for the 1O2 and •O2− generation during BPA degradation elucidated. Moreover, liquid chromatography-mass spectrometry results identified degradation intermediates of BPA, proposing three possible degradation pathways.

Cyclohexane dehydrogenation: Critical evaluation of parameter estimation procedures for kinetic modeling

In the present paper a comparison between different parameter estimation procedures commonly used for the kinetic modeling of chemical reaction is performed, based on experimental measurements of the cyclohexane dehydrogenation to benzene. The obtained results show that, when the Arrhenius equation parameters are estimated from estimates of the rate constant taken at different temperatures, larger parameter uncertainties and correlations are obtained, particularly when the variances of the experimental measurements are not considered during the estimation process. It is also observed that an apparent kinetic compensation effect occurs when the experimental data are separated according to the inlet partial pressure and catalyst mass in the reactor, mainly due to the existing and unavoidable experimental uncertainties and parameter correlations. Additionally, it is shown that larger uncertainties and correlations are obtained when the parameter estimates are computed through the differential method, which can also lead to poorer model predictions of the experimental data. Finally, it is shown that the simultaneous one-step estimation of all model parameters through the integral method and considering the available experimental uncertainties can provide the most accurate parameter estimates, making use of mathematical expressions that describe how variances of the experimental measurements depend on the experimental conditions.

Advancements in covalent organic framework‐based nanocomposites: Pioneering materials for CO2 reduction and storage

AbstractThe persistent increase in atmospheric carbon dioxide (CO2) concentration poses a significant contemporary challenge. Contemporary chemistry is heavily focused on sustainable solutions, particularly the photo‐/electrocatalytic reduction of CO2 and its utilization for energy storage. Despite promising prospects, efficient chemical CO2 conversion faces obstacles such as ineffective CO2 uptake/activation and catalyst mass transport. Covalent organic frameworks (COFs) have emerged as potential catalysts due to their precise structural design, functionalizable chemical environments, and robust architectures. COF‐based materials, especially those incorporating diverse active sites like single metal sites, metal nanoparticles, and metal oxides, hold promise for CO2 conversion and energy storage. This review sheds light on CO2 photoreduction/electroreduction and storage in Li‐CO2 batteries catalyzed by COF‐based composites, focusing on recent advancements in integrating COFs with nanoparticles for CO2 reduction. It discusses design principles, synthesis methods, and catalytic mechanisms driving the enhanced performance of COF‐based nanocomposites across various applications, including electrochemical reduction, photocatalysis, and lithium CO2 batteries. The review also addresses challenges and prospects of COF‐based catalysts for efficient CO2 utilization, aiming to steer the development of innovative COF‐based nanocomposites, thus advancing sustainable energy technologies and environmental stewardship. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

A novel redox synergistic mechanism of peroxymonosulfate activation using Pd-Fe3O4 for ultra-fast chlorinated hydrocarbon degradation

Peroxymonosulfate (PMS)-based heterogeneous advanced oxidation processes for chlorinated hydrocarbons (CHCs) removal in groundwater face the challenge of limited degradation ability. In this work, recyclable catalysts composed of Pd and Fe3O4 nanoparticles were synthesized to activate PMS and generate oxidative HO• and SO4•− and reductive H•, simultaneously. The synergistic attack of different active species led to the ultra-fast degradation and mineralization of multiple CHCs. For trichloroethylene (TCE) degradation, the catalysts mass normalized reaction rate constant of Pd-Fe3O4/PMS system (30.85 L g−1 min−1) was one order of magnitude higher than reported PMS activation systems. The d-band center of Pd in Pd-Fe3O4 was close to the Fermi level, indicating that Pd(0) sites of Pd-Fe3O4 was more conducive to the activation of PMS. In addition, PMS attached Fe3O4 sites caused internal electron transfer to Pd(0) for H• generation. Higher than 97 % of CHCs removal efficiency in continuous flow experiment demonstrated the application potential of Pd-Fe3O4/PMS system.

Controlled Catalyst Layer Architectures for Fuel Cell Applications

The catalyst layer composition and architecture play a pivotal role in bridging the gaps between ex situ and in situ catalyst activities in fuel cells.1 The catalyst-support architecture strongly influences the catalyst distribution, ionomer distribution and mass transport losses, occurring at high current density.2 Herein, a novel architecture based on self-standing fiber-network has been fabricated and characterized.3 The resulting porous structure of such catalyst layer is expected to control mass transport limitation across both the interface of catalyst layer by increasing the number of Triple Phase Boundaries. Further platinum catalyst is deposited onto this fibrous support as well as the ionomer. The full electrode is characterized for its morphology and electrochemically verified in both ex situ as well as in situ configurations. References (1) Jiantao Fan, Ming Chen, Zhiliang Zhao, Zhen Zhang, Siyu Ye, Shaoyi Xu, Haijiang Wang & Hui Li, “Bridging the Gap between Highly Active Oxygen Reduction Reaction Catalysts and Effective Catalyst Layers for Proton Exchange Membrane Fuel Cells”, Nature Energy, 6, 475–486, (2021).(2) Nagappan Ramaswamy, Wenbin Gu, Joseph M. Ziegelbauer and Swami Kumaraguru, “Carbon Support Microstructure Impact on High Current Density Transport Resistances in PEMFC Cathode”, Journal of The Electrochemical Society ,167, 064515, 2020.(3) Giorgio Ercolano, Filippo Farina, Sara Cavaliere, Deborah J. Jones and Jacques Rozière, “Towards Ultrathin Pt Films on Nanofibers by Surface-Limited Electrodeposition for Electrocatalytic Applications”, Journal of Materials Chemistry A , 5, 3974–3980, 2017.

Integrating Experimental and Numerical Data for Improved Steam Reforming Simulation with Deep Learning

Abstract In this paper, a data-driven methane steam reforming simulation is developed and used to predict the post-reaction mixture composition. Until today, methane steam reforming remains a predominant hydrogen production method, yet modeling its complex reactions remains a significant challenge due to the intricate interplay of process variables. Here, we show an artificial neural network simulator that can effectively model these reactions, offering precise predictions based on parameters like temperature, inlet gas composition, methane flow, and nickel catalyst mass. Our approach to data curation integrates experimental, interpolated, and theoretically calculated values and refining the model by assessing the relative importance of each data category. Various neural network structures were tested before ultimately identifying an optimal architecture with a 5-6-8-6-4 network structure. The network underwent 6000 epochs of training, leading to a model that demonstrates excellent agreement with experimental observations, as evidenced by the mean squared error of 0.000217 and the Pearson correlation coefficient of 0.965. Moreover, all process trajectories predicted by the network are characterized by a smooth course and are within a physical range of values. Therefore, this work overcomes a common challenge in chemical process simulation using neural networks and also sets a possible direction for future research in this field.

Magnetic composite photocatalyst NiFe₂O₄/ZnIn₂S₄/biochar for efficient removal of antibiotics in water under visible light: Performance, mechanism and pathway

The widespread presence of antibiotics in aquatic environments, resulting from excessive use and accumulation, has raised significant concerns. A NiFe₂O₄/ZnIn₂S₄/Biochar (NFO/ZIS/BC) magnetic nanocomposite was successfully synthesized, demonstrating significantly enhanced electron-hole separation properties. Comprehensive investigations were conducted to evaluate the impact of various parameters, including catalyst mass, pH, and the presence of co-existing ions on the composite's performance. The nanoparticles of NiFe₂O₄ (NFO) and ZnIn₂S₄ (ZIS) were found to improve the surface stability and sulfamethoxazole removal capabilities of porous biochar, while also demonstrating high total organic carbon removal efficiencies. •O₂⁻ and h⁺ were identified as the predominant reactive oxygen species (ROS) in NFO/ZIS/BC-4 during the degradation process. The degradation outcomes of sulfamethoxazole under natural sunlight and water conditions were consistent with laboratory findings, affirming the robust applicative potential of NFO/ZIS/BC. Density functional theory (DFT) calculations were performed to elucidate the photocatalytic mechanism and identify potential intermediate products. Additionally, the types of heterojunctions present in the system were characterized and discussed. After multiple iterations, NFO/ZIS/BC-4 maintained effective photodegradation capabilities through five cycles. This study presents an effective method for the treatment of antibiotics in aquatic environments, offering significant potential for environmental applications.

Numerical investigation of methane steam reforming in the packed bed installed with the fin-metal foam

Methane steam reforming via packed bed reactors currently is the primary method for industrial hydrogen produce worldwide. Optimizing the structure of packed bed reactors is an effective approach to enhance the hydrogen yield. This study introduces an innovative structure, the fin-metal foam, combined into a packed bed reactor. A numerical investigation was conducted by the new coupling simulation way, which consists of the equivalent medium model, the Darcy extended Forchheimer flow model and the local thermal non-equilibrium model. A conventional reactor, a reactor installed with a metal foam and a reactor installed with the fin-metal foam were compared. It was found that the fin-metal foam structure improves the performance of flow, heat transfer and hydrogen production. By comparing with the conventional reactor, the fin-metal foam structure reduces the energy dissipation by 35.13 %, increases the fluid temperature by 23 K and improves the overall heat transfer coefficient by 28.59 %. The hydrogen mass flow per catalyst mass per energy dissipation was employed to evaluate the comprehensive hydrogen production performance. The fin-metal foam structure leads to a notable improvement of 113.36 %. These findings suggest a promising way for improving the industrial hydrogen produce, with benefits including reduced energy consumption and catalyst usage.

RGO-MoO3 Nanocomposite for superior methylene blue removal by adsorption and photocatalysis

Efficient MoO3 and rGO (0.5,1,2 wt.%)-MoO3 nanosorbent was prepared by facile hydrothermal method. X-ray diffraction (XRD) and Raman spectroscopy techniques confirms the orthorhombic phase. Remarkably in 10 ppm MB dye, complete removal was observed for 1:3, 1:5, 1:3.3, 1:3 (mass of catalyst: volume of dye solution) ratio for pure, 0.5 wt.%, 1 wt.%, 2 wt.% rGO-MoO3 nanocomposite, by merely stirring for one hour without any light exposure. The adsorption mechanism was examined in detail using different models including Langmuir isotherm and Pseudo second-order kinetic model. The composite sample, rGO (0.5 wt.%)-MoO3 is the most efficient nanosorbent whereas rGO (2 wt.%)-MoO3 showed the least adsorption. rGO (2 wt.%)-MoO3 was further used for time dependent study in the presence of UV and in the dark. The presence of UV enhances removal due to the combined effect of adsorption and photocatalysis. Scavenger studies were performed to analyze the mechanism of photocatalysis.