N2 Atmosphere Research Articles

Three-dimensional cage based on porous Ni–Co–Cu phosphide as efficient and stable bifunctional electrocatalysts for overall water splitting

The development of cheap and high-performance dual electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in an electrolyte is of great importance. Tuning the electronic structure through heteroatom doping and increasing the catalytic sites through designing the morphology of nanostructures are the most popular approaches to enhance electrocatalytic performance. In recent years, with the development of nanotechnology and interface engineering, significant progress has been made in this field, but it is still challenging. Here three-dimensional porous NiCoCu–P cage were synthesized using a quick and easy method with the help of 26-face Cu2O as a sacrificial template, then it was phosphidated by a facile phosphidation heat treatment in N2 atmosphere and then for the electrochemical evaluations, the glassy carbon electrode surface (GCE) surface was modified with it. Taking advantage of these strategies, NiCoCu–P cage offer large surface area, fast electron/mass transfer and open channels for efficient gas release, which show improved electrochemical performance in alkaline environment and achieved an overpotential of −210 mV at 10 mA cm−2 for HER and 240 mV at 50 mA cm−2 for OER. Also, an overall water splitting device is assembled by two symmetric NiCoCu–P cage/carbon cloth as cathode and anode, that can provide a current density of 100 mA cm−2 at a cell voltage of less than 1.6 V.

Polymer-derived Biosilicate-C composite foams: In-vitro bioactivity, biocompatibility and antibacterial activity

Biosilicate/carbon composites were fabricated in the form of highly porous foams by the polymer-derived ceramic route, and their biological response was analysed. Two different commercial silicone polymers (a poly-methyl-siloxane, MK, and a polymethyl-phenyl-silsesquioxane, H44) were considered as a silica source, mixed with active fillers yielding Na2O, CaO and P2O5. The samples were heat treated either in air or in N2 atmosphere to obtain products resembling the known Biosilicate® glass-ceramic, with or without free carbon. All fabricated samples exhibited acellular in-vitro bioactivity upon immersion in SBF as well as antibacterial activity against S. aureus and E. coli. Direct contact cell viability test, assessed by using a WST-8 assay, indicated that both carbon-containing and carbon-free samples were cytocompatible.

Synergistic Interaction between Metal Single-Atoms and Defective WO3- x Nanosheets for Enhanced Sonodynamic Cancer Therapy.

Although metal single-atom (SA)-based nanomaterials are explored as sonosensitizers for sonodynamic therapy (SDT), they normally exhibit poor activities and need to combine with other therapeutic strategies. Herein, the deposition of metal SAs on oxygen vacancy (OV)-rich WO3- x nanosheets to generate a synergistic effect for efficient SDT is reported. Crystalline WO3 and OV-rich WO3- x nanosheets are first prepared by simple calcination of the WO3 ·H2 O nanosheets under an air and N2 atmosphere, respectively. Pt, Cu, Fe, Co, and Ni metal SAs are then deposited on WO3- x nanosheets to obtain metal SA-decorated WO3- x nanocomposites (M-WO3- x ). Importantly, the Cu-WO3- x sonosensitizer exhibits a much higher activity for ultrasound (US)-induced production of reactive oxygen species than that of the WO3- x and Cu SA-decorated WO3 , which is also higher than other M-WO3- x nanosheets. Both the experimental and theoretical results suggest that the excellent SDT performance of the Cu-WO3- x nanosheets should be attributed to the synergistic effect between Cu SAs and WO3- x OVs. Therefore, after polyethylene glycol modification, the Cu-WO3- x can quickly kill cancer cells in vitro and effectively eradicate tumors in vivo under US irradiation. Transcriptome sequencing analysis and further molecular validation suggest that the Cu-WO3- x -mediated SDT-activated apoptosis and TNF signaling pathways are potential drivers of tumor apoptosis induction.

Study on the Migration and Release of Sulfur during the Oxidizing Roasting of High-Sulfur Iron Ore

In China, most of the high-sulfur iron ores have not been fully developed and utilized due to the lack of breakthrough progress in the research on the sulfur migration and the desulfurization mechanism during the roasting process. This study will focus on revealing the release and fixation mechanisms of sulfur during the roasting process to achieve the transformation of desulfurization from terminal treatment to process control. Experimental results show that as the roasting temperature increases, the release rate of SO2 also increases, reaching the maximum release rate at 900 °C. Simultaneously, it is found that at the same roasting temperature, the release rate and amount of SO2 under the O2/N2 atmosphere is significantly greater than that under the pure N2 and air atmospheres. Meanwhile, X-ray diffraction (XRD) is utilized to explore the phase composition of the roasted product and the sulfur release mechanism. In addition, the adsorption energy, stability and electron transfer of SO2 on the CaO surface are calculated through density functional theory (DFT), and the optimal adsorption active site perpendicular to the O atom (O-top) is also determined. Finally, the sulfur fixing agent CaO is used to study the SO2 fixation mechanism. When the concentration reaches 10%, the sulfur fixation efficiency reaches more than 80%. Therefore, this work will present basic knowledge and systematic guidance for the sulfur migration and release of high-sulfur iron ore under the oxidizing roasting process.

A Ferrocene Capping Layer Enabling Highly Efficient and Stable Sn–Pb Mixed Perovskite Solar Cells

The Sn–Pb mixed perovskite with a narrow bandgap is essential for the construction of all‐perovskite tandem solar cells. However, the oxidation of Sn2+ to Sn4+ makes the fabrication of Sn–Pb perovskite solar cells (PSCs) challenging. Herein, a ferrocene (Fc) capping layer is introduced on the surface of Sn–Pb mixed perovskite to maintain a reducing environment. This is due to a strong electron supply capacity from the π‐orbitals in cyclopentadiene in Fc, which effectively suppresses the oxidation of Sn2+, reduces the defect density, and leads to an improvement in carrier lifetime. Therefore, the Fc capping layer significantly improves the power conversion efficiency (PCE) of single‐junction Sn–Pb PSCs from 17.49% to 21.02%. It maintains 87% of its initial PCE after light exposure at 1 sun condition in N2 atmosphere for 288 h, demonstrating good long‐term stability. The strategy outlined herein offers a straightforward and efficient approach to enhance the stability and PCE of narrow‐bandgap Sn–Pb mixed PSCs.

Equilibrium, kinetic, and thermodynamic study of Direct Yellow 12 dye adsorption by biomass-derived porous graphitic activated carbon

AbstractCompetent treatment techniques were explored to curb the environmental pollution of dye-laden wastewater. In the current study, eucalyptus biomass contemplated as agricultural waste is translated into eucalyptus graphitic activated carbon (EPGAC) using ZnCl2 at 600 °C in the N2 atmosphere. The present investigation illustrated awareness about the nature of EPGAC’s dye elimination by employing Direct Yellow 12 dye (DY12) as a model dye. EPGAC was characterized using multiple characterization tools such as Fourier transform infrared spectroscopy (FTIR), Boehm titrations, pHzpc, X-ray diffraction (XRD), Raman, field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX), high-resolution transmission electron microscopy (HRTEM), and Brunauer-Emmett-Teller (BET) surface area analysis techniques. Electron micrographs disclosed the availability of high pore density for the adsorption of DY12 dyes. BJH analysis reported the distribution of mesopores having a 3 nm diameter on the EPGAC surface. Further, the surface area available for adsorption per gram of the adsorbent is estimated as 178.35 m2 employing BET analysis. XRD and Raman’s data revealed the graphitic nature of EPGAC. Influences of adsorbent parameters such as EPGAC mass, initial dye concentration, contact time, solution pH, and temperature on the eviction of DY12 by EPGAC were examined to achieve a deeper insight into the adsorption mechanism. The optimum EPGAC adsorbent dose was found to be 0.15 g. The equilibrium was attained at 120 min for DY12 dye. Pseudo-second-order kinetics entirely relates to the perfect fit associated with the investigational results. The aptness of the equilibrium data relevant to the Langmuir adsorption isotherm eventually recommends a maximum unilayer adsorption capacity of 42.01 mg/g for EPGAC. Thermodynamic studies further reveal the spontaneous, endothermic, and chemisorption nature of adsorption. Adsorbent viability was established through stability and recyclability studies carried out up to 5 run cycles with 0.15 g of EPGAC. Adsorption mechanisms were explained considering hydrogen bonding, π-π interactions, and electrostatic interactions, ultimately confirming the adsorption tendency displayed by EPGAC for the eviction of DY12 dye present in industrial wastewater.

Electrochemical detection of paracetamol using zeolitic imidazolate framework and graphene oxide derived zinc/nitrogen-doped carbon

A composite of zeolitic imidazolate frameworks and graphene oxide (ZIF-GO) derived 3D–2D Zn/N-doped carbon (ZnNC-rGO) was developed for the electrochemical detection of the analgesic paracetamol (PCT). The pyrolysis of ZIF-GO led to the formation of a nanoscale structure featuring ZnNC cubes embedded in rGO sheets. The Zn0-to-ZnO phase transition was found to mediate electrons during the reversible paracetamol redox reactions, which contributed to the sensing current response. Upon 800 °C heating under a N2 atmosphere, the mesoporosity of ZnNC-rGO(800) was significantly enhanced, thereby increasing the electrochemical surface area and charge transfer efficiency. The electrode sensitivity was optimized at a calibration linearity of 0.526 μA μM−1) with detection limit (0.077 μM) in the range of 0.5 – 70 μM using differential pulse voltammetry mode (DPV). The precision of analytical recovery for trace paracetamol concentrations was maintained based on the excellent reproducibility and selectivity trials in the presence of interference chemicals and in real water samples.

Anisotropic and hierarchical porous boron nitride/graphene aerogels supported phase change materials for efficient solar-thermal energy conversion

The formation of shape-stabilized composite phase change materials (CPCMs) with special structure is an efficient strategy to prevent the leakage of phase change materials (PCMs) and improve the solar-thermal conversion ability. In this work, graphene and boron nitride nanosheets (BBNS) were prepared by the magnesiothermic reduction SHS method in CO2 and N2 atmosphere, respectively. Then, an anisotropic and hierarchical porous boron nitride/graphene aerogel with three-dimensional network was constructed by directional ice-freezing method using carboxymethyl cellulose as supporting framework and adhesive, and polyethylene glycol (PEG) was impregnated to prepare novel CPCMs. The CPCMs had enthalpies of 150∼160 J/g, and a highest thermal conductivity of 0.390 W/(m·K), which was around 47% higher than that of pure PEG. The ability of the CPCMs to convert solar energy to thermal energy was significantly enhanced. Under a simulated light intensity of sunlight (100 mW/cm2), its solar-thermal conversion efficiency reaches 94.92%, and after 20 min of irradiation, the surface temperature can reach 72 °C. These CPCMs are promising for the efficient use of renewable solar energy due to their high solar-thermal conversion efficiency and thermal storage capabilities.

Structural Parameters and Behavior in Simulated Body Fluid of High Entropy Alloy Thin Films.

The structure, composition and corrosion properties of thin films synthesized using the Pulsed Laser Deposition (PLD) technique starting from a three high entropy alloy (HEA) AlCoCrFeNix produced by vacuum arc remelting (VAR) method were investigated. The depositions were performed at room temperature on Si and mirror-like polished Ti substrates either under residual vacuum (low 10-7 mbar, films denoted HEA2, HEA6, and HEA10, which were grown from targets with Ni concentration molar ratio, x, equal to 0.4, 1.2, and 2.0, respectively) or under N2 (10-4 mbar, films denoted HEN2, HEN6, and HEN10 for the same Ni concentration molar ratios). The deposited films' structures, investigated using Grazing Incidence X-ray Diffraction, showed the presence of face-centered cubic and body-centered cubic phases, while their surface morphology, investigated using scanning electron microscopy, exhibited a smooth surface with micrometer size droplets. The mass density and thickness were obtained from simulations of acquired X-ray reflectivity curves. The films' elemental composition, estimated using the energy dispersion X-ray spectroscopy, was quite close to that of the targets used. X-ray Photoelectron Spectroscopy investigation showed that films deposited under a N2 atmosphere contained several percentages of N atoms in metallic nitride compounds. The electrochemical behavior of films under simulated body fluid (SBF) conditions was investigated by Open Circuit Potential (OCP) and Electrochemical Impedance Spectroscopy measurements. The measured OCP values increased over time, implying that a passive layer was formed on the surface of the films. It was observed that all films started to passivate in SBF solution, with the HEN6 film exhibiting the highest increase. The highest repassivation potential was exhibited by the same film, implying that it had the highest stability range of all analyzed films. Impedance measurements indicated high corrosion resistance values for HEA2, HEA6, and HEN6 samples. Much lower resistances were found for HEN10 and HEN2. Overall, HEN6 films exhibited the best corrosion behavior among the investigated films. It was noticed that for 24 h of immersion in SBF solution, this film was also a physical barrier to the corrosion process, not only a chemical one.

Characterization of a hyperbolic vortex plasma reactor for the removal of aqueous phase micropollutants

The present study focuses on the characterization of a hyperbolic vortex plasma reactor through the comparison of various plasma-atmospheric regimes for the production efficiency of reactive nitrogen (RNS) and reactive oxygen (ROS) species. The research also explores effectiveness in the removal of micropollutants, including pharmaceuticals and per- and polyfluoroalkyl substances (PFAS). The technology includes several degradation mechanisms, such as advanced oxidation, ultraviolet photolysis, ozonation, electrolysis, and shockwave water purification, without the need for additional chemicals. Our results indicate that the plasma of bipolar or ‘flashover’ mode is notably more effective and efficient than both positive or negative polarity. Through the testing of various energy levels, it has been demonstrated that higher energy plasma yields lower efficiency but necessitates shorter treatment times compared to lower energy treatment. When plasma is produced under ambient atmosphere, water chemical properties change significantly in comparison to treatment under argon (Ar) or nitrogen (N2) due to the presence of both oxygen and N2 molecules. In a N2 atmosphere, the predominant formation is of RNS due to the chemical reactivity of N2 exited states, whereas under Ar atmosphere, predominantly ROS are generated. Notable advantages of this technology are its scalability and its low energy requirements. The scalability of the technology involves increasing the size of the reactor, the power and electrode count.

Carbon fiber paper based on composites of carbon and polyacrylonitrile for fuel cell application

Carbon fiber paper is one of the most important substrates used in the gas diffusion layer of the polymer electrolyte membrane fuel cell. A novel approach to creating carbon fiber paper using polyacrylonitrile compounds was proposed in this study. The technique incorporated varying amounts of carbon materials, including carbon black (Vulcan), graphite powder, and carbon nanotubes. Polyacrylonitrile carbon materials were prepared through the spinning process, followed by oxidative stabilization under an oxygen atmosphere at a temperature range of 160–300 °C as the first step. The pliable material undergoes a conversion process to create a compound or ladder that is non-plastic, which is then stabilized in an N2 atmosphere. The fibers are then pre-carbonized at temperatures ranging from 300 to 600 °C and further carbonized between 600 and 1100 °C. After that, Teflon is added and the resulting fibers are made into sheets during the production process. Finally, physical measurements and electrochemical methods such as: checking the amount of water absorption, scanning electron microscope (SEM), chronopotentiometry, electrochemical impedance spectroscopy, electron resistance of carbon sheet, double layer capacitance, and surface roughness parameter were evaluated. The results indicate that the best performance is related to CP7 carbon paper (with a 30–70 % combination of polyacrylonitrile and carbon black).

Preparation and antibacterial properties of β-SiAlON/AlN composite ceramics

In this study, β-SiAlON/aluminum nitride (AlN) composite ceramics were synthesized using a wet-mixing method at 1500 °C under a N2 atmosphere. X-ray diffraction and scanning electron microscopy were used to characterize the ceramics before and after immersing them in water for 7 d. The change in pH and release of ammonia nitrogen were studied to investigate the reaction and antibacterial mechanisms of AlN hydrolysis. The effects of the AlN content on the phase composition, microstructure, chemical properties, and antibacterial efficacy of the composite ceramics were investigated. As the AlN content increased, the antibacterial efficiency gradually increased. The antibacterial efficiency of the composite ceramic with an AlN content of 60 wt% was 100%, indicating that an increase in pH and amount of ammonia nitrogen could synergistically enhance the antibacterial effect. However, in a lysogeny broth medium, the buffering effect of the culture medium and promotion of bacterial proliferation may reduce the antibacterial efficiency. Therefore, β-SiAlON/AlN composite ceramics show considerable potential for antibacterial applications.

Research of aging test on high Tg colorless polyimide

AbstractFor the past few years, colorless polyimide (CPI) has been drawn much attention for its application in transparent electronics. The high temperature (even to 450°C) process of the preparation of organic light‐emitting diode display (OLED) device may have huge challenges on the properties of CPI, so we designed a series of aging test experiments to study the influence of test temperature and atmosphere on the high transparency percentages (Tr%) of CPI films with structure of Glass/SiO2/CPI/SiO2. As the aging temperature increased from 430 to 450°C and then to 470°C, the Tr% of the film decreased significantly. Comparing with the sample without aging, the transmission losses were 0.22%, 1.42%, and 4.82% for the films aging with 430, 450, and 470°C in N2 atmosphere, respectively. Additionally, aging in nitrogen resulted in less Tr% loss (1.22%) compared with air (1.42%). This research offers insights into how to maintain the high Tr% of CPI films during high‐temperature processing. Furthermore, it supports the development of more durable and reliable CPI‐based components for OLED displays and other transparent electronic devices. This can lead to advancements in the performance of these devices, potentially extending their lifespan and broadening their range of applications.

Ignition characteristics of single coal particles under ammonia co-firing conditions

To meet the goal of an international carbon-neutral framework, the promotion of clean coal utilization occupies a vital position in reducing greenhouse gas emissions. Ammonia co-firing is considered as a potential strategy for future power generation to reduce fossil energy consumptions, soot, CO2 emissions, and hydrocarbon pollutants. In the present work, the ignition characteristics of single coal particles under ammonia (NH3) co-firing conditions were investigated. Particles were injected with NH3 or N2 into a hot flue gas environment at 1550 K generated by a CH4-fired Hencken burner. Temporally resolved images of CH* chemiluminescence and char thermal radiation were captured. Combining the signal profiles, ignition modes and characteristic times of single burning particles were studied with different coal types, carrying atmospheres, and O2 contents. When the carrier gas was replaced by NH3 atmosphere, the ignition delay time of all coal particles was greatly shortened, and the time interval from ignition to peak, as well as the combustible component burnout time, were both lengthened due to the promoted devolatilization and combustion reaction rates of coal particles caused by the NH3 flame. Concerning the ignition mode in the NH3-blended cases, the homogeneous ignition behaviors of the lignite particles were further enhanced, while the bituminous particles transitioned to the homogeneous-heterogeneous united ignition mode. As the O2 content in the flue gas increased, the ignition of all coal particles was advanced monotonously, and the chemiluminescence became more intense in both N2 and NH3 atmospheres.

Efficient and robust ultrathin porous carbon encapsulated Ni–Sn intermetallic compounds derived from metal–organic frameworks for in-situ aqueous phase deoxygenation of fatty acid methyl esters

Deoxygenation of fatty acid esters in aqueous phase using in-situ generated H2 has emerged as a promising approach to producing sustainable diesel-like hydrocarbons. In this study, we employed a solvothermal method to synthesize novel Ni–Sn metal–organic frameworks (MOFs) with a homogeneous distribution of Ni and Sn elements. Subsequently, various Ni–Sn intermetallic compounds (IMCs) encapsulated with a porous carbon layer (<3 nm) (Ni–Sn IMC@C) were prepared through the facile pyrolysis of metal–organic frameworks under a controlled N2 atmosphere. Applying methyl palmitate as model reactant and methanol as hydrogen donor, Ni3Sn2 IMC@C gives approximately 100% conversion and 93% yield towards n-C15 and n-C16 alkanes at 330 °C, without significant deactivation during the recycling for five times. The deoxygenation pathway is dominated by decarbonylation (DeCO) on Ni–Sn IMCs. In Ni–Sn IMCs, the oxophilic nature of Sn, along with its charge transfer with Ni, enhances the adsorption of an η2(C, O)-aldehyde configuration. The strategic isolation of adjacent Ni by Sn effectively inhibits methanation and C–C bond hydrolysis, reducing H2 consumption and increasing carbon yield. Moreover, the ultrathin porous carbon encapsulation not only prevents the loss and sintering of Ni3Sn2 IMC under harsh hydrothermal condition but also mitigates mass transfer limitation. Surface oxidation of Ni3Sn2 IMC, particularly the formation of SnO2, is detrimental to deoxygenation. Additionally, Ni3Sn2 IMC@C exhibits high hydrocarbon yields (>89.6%) in in-situ aqueous phase deoxygenation of methyl laurate, methyl stearate and methyl oleate. These findings highlight the remarkable potential of MOF-derived catalysts for hydrothermal deoxygenation.

Effective surface passivation for stable and high-performance inverted CsPbI2Br perovskite solar cells with efficiency over 15%

Inverted CsPbI2Br perovskite solar cells (PSCs) still suffer from substantially non-radiative recombination losses at the perovskite interface, which limits the future advancement of CsPbI2Br perovskite-based single- and multi-junction photovoltaic cells. Interfacial defect passivation of perovskite films is an effective approach for enhancing the performance of PSCs. In this study, we introduce thiophene halide salts with different side groups on the surface of CsPbI2Br films to passivate the inorganic perovskite film and investigate their passivation effects. Our studies show that the 2-thiophenemethylammonium iodide (TM) passivator with –CH2NH3I side group effectively mitigates the trap density of the perovskite film by forming coordination bonding with Pb2+ ions, thus significantly inhibiting the non-radiative recombination in the resulting PSC. In addition, after the TM treatment, the better energy-level alignment between the CsPbI2Br/[6,6]-Phenyl C61 butyric acid methyl ester (PCBM) interface is achieved, thus enhancing the charge extraction from perovskite to the charge transport layer. The resulting inverted CsPbI2Br device demonstrates a significantly enhanced champion efficiency of 15.07% with a Voc of 1.16 V, Jsc of 16.42 mA/cm2, and FF of 79.11%, compared to the 11.19% efficiency of the control device, and maintains >97% of the initial efficiency after being stored for over 1700 h in N2 atmosphere. This work confirms the importance of substituent groups on surface passivation molecules for effective passivation of defects and optimization of energy levels, particularly for Voc improvement.

Excellent ductility of an austenitic stainless steel at a high strength level achieved by a simple process

In the pursuit of simultaneously improving the yield strength and plasticity of austenitic stainless steel, a new austenitic stainless steel was fabricated by induction smelting using a pure N2 atmosphere, hot forging, cryogenic rolling, and annealing. The material was characterized by microstructures with 3–4 μm uniform finer grains, fine precipitates, high thermal stability austenite, and extensive high-angle grain boundaries. The elongation after fracture, yield strength, and ultimate tensile strength of the samples reached 53.5 %, 707 MPa, and 1020 MPa, respectively, as well as 61 %, 600 MPa, and 977 MPa, respectively, at the same time. Moreover, a high strain hardening rate was achieved in the new stainless steel. The appropriate uniform finer grains not only played a role in grain-refined strengthening but also provided intragranular spaces and sufficient mean free available paths for dislocation accumulation and movement. Precipitates, which were coherent or semi-coherent with the matrix, provided interfaces for dislocation accumulation and obstructions for dislocation movement. Extensive high-angle grain boundaries with appropriate finer grains served as another important factor for excellent ductility due to the inhabitation and resulting deviation of crack propagation. In addition, strain-induced mechanical twinning in the current austenitic stainless steel contributed to excellent ductility and high strength.

Co-Pyrolysis of Woody Biomass and Oil Shale—A Kinetics and Modelling Study

The co-pyrolysis of biomass and fossil fuels has been the subject of studies on sustainable energy. Co-feeding oil shale with woody biomass can contribute to a transition into carbon neutrality. The present study analysed the thermal decomposition behaviour of oil shale and biomass blends (0:1, 3:7, 1:1, 7:3, 9:1, and 1:0) through thermogravimetric analysis (TGA) at 80–630 °C with a heating rate of 10 °C/min in CO2 and N2 atmospheres. A comparison of theoretical and experimental residual mass yields of oil shale–biomass mixtures indicated no significant interactions between the fuels. The blends contributed to a decrease of up to 34.4 wt% in solid residues compared to individual pyrolysis of oil shale, and the TGA curves were shifted from up to 10 °C to a lower temperature when the biomass ratio increased. The use of a CO2 atmosphere resulted in the production of solid residues, comparable to the one obtained with the N2 atmosphere. CO2 atmosphere can be used in oil shale–biomass co-pyrolysis, without affecting the decomposition process or increasing the yield of residues. A kinetic model method is proposed based on TGA data at 10, 20, and 30 °C/min. The apparent activation energies for a temperature range of 200–520 °C were in the order of 139, 155, 164, 197, 154, and 167 kJ/mol for oil shale–biomass 0:1, 3:7, 1:1, 7:3, 9:1, and 1:0 blends, respectively. From the isoconversional kinetic analysis, a two-stage pyrolysis was observed, which separated biomass and oil shale pyrolysis. A simulation of biomass and oil shale co-pyrolysis was conducted in Aspen Plus® using TGA-derived kinetic data. The model prediction resulted in a close match with the experimental thermogravimetric data with absolute errors from 1.75 to 3.78%, which highlights the relevance of TGA analysis in simulating co-pyrolysis processes.

Research on preparation of high activity and durable carbon-supported platinum catalyst for methanol electro-oxidation by a facile continuous microwave pipeline method

In methanol oxidation reaction (MOR), it is crucial for the catalyst that Pt particles uniformly cover the surface of the carrier and the Pt surface active sites can effectively remove the binding with CO. This article develops a simple and effective continuous microwave technology. Carbon loaded nano platinum was synthesized by rapidly and uniformly heating a ethylene glycol mixture containing carbon black (CB) H2PtCl6 using microwave radiation, with a Pt content of 49.5%. The experimental results indicate that platinum particles are uniformly loaded onto the carbon surface, with uniform shape and size, and an average particle size of 3.02 nm. And the Pt/C catalyst prepared by continuous microwave technology showed enhanced electrocatalytic activity (peak current density of 76.95 mA/cm2) in MOR after heating at appropriate temperature in N2 atmosphere, which exceeded the commercial catalyst TKK (47.07 mA/cm2) by 63.6%. And the catalyst's resistance to CO toxicity and durability; Higher than commercial Pt/C catalysts. Compared with traditional methods, continuous microwave technology exhibits higher energy utilization efficiency and faster reaction speed in the catalyst preparation process. This technology also has the ability to achieve continuous preparation, which is one of the effective technological approaches to achieve large-scale catalysts production.

Mechanistic and experimental study of VxCy nitridation in N2 atmosphere to prepare high-quality vanadium nitride

Vanadium nitride (VN) serves as a versatile material in various applications such as electrodes, ceramics, catalysts, and alloy components owing to its robust electrical performance, favorable stability, and high hardness. However, conventional VN synthesis methods require long soaking times and high temperatures. This study investigates a method wherein VxCy powder was soaked in an N2 atmosphere for a shorter period of time at a lower temperature to produce high-quality VN particles. The mechanism underlying this process was investigated via thermodynamic analyses, ab initio molecular dynamics (AIMD) simulations, and experimental studies. Thermodynamic analysis validates the thermodynamic feasibility of the reactions between VxCy and N2 to produce VN, while the atomic-level interactions between VxCy, N2, and surplus C atoms were comprehensively elucidated. By analyzing the two systems, it was discovered that the surplus C promoted the combination of N2 molecules with V atoms to form V–N in shorter AIMD simulation durations. Surplus C increased the chance of N2 molecules and V atoms to contact, similar to a catalytic effect, by activating N2 molecules to decompose and further reacted with V atoms to form VN. According to the experimental results, high-quality VN particles were formed at a heating temperature of 1323 K and soaking period of 90 min. Field-emission scanning electron microscopy (SEM) coupled with energy-dispersive spectrometry (EDS), particle size distribution analysis, and X-ray diffraction (XRD) were used to characterize the final product. The O and N contents were measured by an O/N analyzer at 0.11% and 17.4%, respectively. Accordingly, a C/S analyzer measured the C content at 3.92%. These analyses indicate that high-quality VN can be obtained by the VxCy nitridation in N2 atmosphere.