Transfer Kinetics Research Articles

Fermi level regulation of single-walled carbon nanotubes by metal chloride doping for enhanced NO2 sensing performance

Pristine single-walled carbon nanotubes (SWCNTs) typically exhibit limited sensitivity due to the low charge transfer dynamics between nanotubes and gas molecules. Among various enhancement methods, the Fermi level regulation proves to be effective in promoting the charge transfer between SWCNTs and gas molecules, consequently improving the sensing performance. Herein, we firstly report a non-destructive method to regulate the Fermi level of SWCNTs through doping metal chlorides, and the interfacial charge transfer between SWCNTs and different metal chlorides has been well investigated by combining Raman shift with X-ray photoelectron spectroscopy. Experimental results reveal that the interfacial charge transfer dynamics determine the sensing properties of SWCNTs doped with chlorides. The as-fabricated FeCl3-doped SWCNT sensors exhibit a high response of 196.9 % in response to 100 ppb NO2 gas with excellent selectivity. The Kelvin probe force microscope (KPFM) results directly prove the doping effect of metal chlorides due to the shift down of Fermi level of SWCNTs after doping FeCl3. Our work not only proposes a novel method to controllably regulate the Fermi level of SWCNTs but also provides a guidance for high-performance SWCNT-based sensing devices.

Self-driven transport and heat transfer characteristics of a droplet on a wettability-gradient surface by front-tracking method

Droplet manipulation is a multidisciplinary field with broad applications across various industries. It holds significant potential in areas such as microfluidics, oil–water separation, water harvesting, and heat transfer. However, there is still a lack of comprehensive knowledge regarding droplet migration on restricted surfaces. In this study, we conducted a numerical simulation using the front-tracking method to investigate the heat transfer associated with droplet migration on a cold plate with a wettability gradient. We examined the effects of relative temperature differences, surface wettability, low initial impact velocities (We≤10), and wettability constraints (the width of the wettability stripe capable of driving droplet movement) on various droplet-related heat transfer characteristics and the resulting temperature field distribution. Our key findings indicate that as the temperature difference between the droplet and the surface increases, the heat flux experienced by the droplet after deposition also increases. Additionally, the decline in the heat flux curve during the descending phase becomes more significant. The surface contact angle plays a crucial role in the heat transfer dynamics during droplet migration. Droplets reach thermal equilibrium more quickly on hydrophilic surfaces with smaller contact angles. Higher initial impact velocities initially cause droplets to rebound on the surface, leading to more pronounced fluctuations in transient heat flux during the impact phase. However, as droplets transition from the rebound phase to the migration phase, the impact velocity's influence diminishes. Additionally, the restricted wettability (W*) affects the droplet-surface heat transfer through variations in the wetting area. We observed a fourfold difference in the relative wetting area between W*=0.4 and W*=2.5 in the final stage.

Novel S-scheme WO3/ZnO-modified g-C3N4 heterojunction for optimizing norfloxacin photodegradation condition via DoE: Synthesis, characterization, and mechanism evaluation

Norfloxacin, an antimicrobial agent, has been recurrently observed in municipal wastewater facilities, posing a conjectured threat to human health and environmental integrity. Herein, novel ternary heterojunction of WO3/ZnO-modified g-C3N4 was fabricated utilizing the impregnation technique for the organic pollutant degradation, presenting a significant challenge. XRD, XPS, TEM, HR-TEM, SEM, EDS, BET, EIS, Mott-Schottky, ESR, PL, photocurrent, and DRS techniques were used to explore the structural, morphological, textural, and optical features of the produced materials. In this ternary system, ZnO served as an electron transfer conduit, facilitating the formation of a heterojunction interface between the semiconductor constituents. Establishment of the S-scheme within the charge transfer dynamics of the heterojunction markedly augmented charge separation, enhancing the efficacy of the photocatalytic activity. Under optimized conditions via the DoE software (i.e.; photocatalyst dosage: 0.54 g/L, NOR concentration: 25.87 mg/L, Irradiation time: 41.71 min and pH: 6.9), 97.19 % of NOR elimination was achieved by the optimized 20-WZC photocatalyst with a pseudo-first-order kinetic model (k = 0.05 min−1). ESR data, alongside quenching experiments, corroborated the pivotal involvement of O2−, OH, and h+ in the NOR degradation mechanism. The investigation of NOR's potential decontamination pathways was performed using HRLC-MS. TOC analysis revealed a significant mineralization of 82.45 %, indicating the conversion of NOR into H2O, CO2, and other degradable substances. The optimized photocatalyst also demonstrated notable efficiency in the degradation of Tetracycline: 98.15 %, Ciprofloxacin: 93.27 %, Methylene Blue: 98.89 %, and Enrofloxacin: 91.54 % pollutants. The photocatalytic activity of the 20-WZC catalyst remained consistently high, without significant reduction, over five successive cycles.

Simulation Study on Heat and Moisture Transfer in Cross‐Flow Drying Aeration of Bulk Corn in a Cone‐Bottom Silo Using Natural and Low‐Temperature Air

ABSTRACTUsing variable temperature and relative humidity of natural air based on local climatic conditions for natural drying aeration of grain is an energy‐saving and efficient method. The study of heat and moisture transfer within grain piles during natural air and low‐temperature air drying aeration of bulk corn in low‐humidity areas, which can provide theoretical support for selecting efficient and low‐consumption grain drying processes and practical applications. In this study, the mathematical model of the coupled heat and moisture transfer dynamics in the dry silo was verified using experimental datum of grain storage drying aeration experiment, and the relative error was less than 5% between the simulated and the experimental datum. Based on this validated model, the temperature and moisture content variations of in‐silo bulk corn drying were simulated by computational fluid dynamics (CFD) numerical simulation techniques. The simulations included continuous drying aeration with daily average, hourly average temperature and relative humidity of the local natural air, and low‐temperature air drying aeration with heated up to 3°C over the ambient temperature, as well as intermittent drying aeration. Drying effectiveness and economic efficiency were also analyzed and evaluated. The costs for continuous drying aeration with hourly average of natural air and low‐temperature, intermittent drying aeration with hourly average of natural air are 0.032, 0.042, and 0.016 CNY/kg, respectively. Compared to traditional high‐temperature hot air drying, the costs of these methods were reduced by 0.048, 0.038, and 0.064 CNY/kg, respectively.

Thermal performance analysis of PCM-integrated structures using the resistance-capacitance model: Experiments and numerics

While holding significant potential to reduce cooling energy requirements in buildings, the incorporation of phase-change materials in building envelopes requires information regarding their diurnal and seasonal behaviour through high-fidelity simulations. However, utilizing short-term simulations and experimentation using state-of-the-art models for such a complex configuration does not accurately represent the true heat transfer dynamics of the building. To address this lacuna, we present a physics-based, low computational cost, experimentally and numerically validated resistance–capacitance (RC) model specifically tailored for PCM-encapsulated structures, designed for long-term simulations. The validation of this model is conducted through in-house experiments. Additionally, we support the credibility of our RC model by subjecting it to validation through 3D numerical simulations, emphasizing its precision and reliability. Then, we use the validated model to optimize the thermal properties of concrete roofs in hot and dry climates, taking a specific instance of a city in Western India for various geometric configurations as an illustrative example. We find that a PCM with a phase change temperature between 37 and 42 °C can reduce the peak ceiling temperature by up to 10 °C and the peak energy ingress by a factor of 2 or more, in a typical roof element subjected to the prevailing climatic conditions during peak summer. This shows the time constant of the modified roof is effective in delaying and damping the imposed solar insolation. We make specific recommendations on the selection and geometry optimization of PCM-incorporated roof elements.

Continuous flow photocatalytic reactor for degradation of selected pollutants: Modeling, kinetics, mineralization rate, and toxicity assessment

This study focused on developing and evaluating a continuous flow photoreactor with an immobilized photocatalyst. The titanium dioxide powder was deposited on glass beads and packed into sequentially connected columns surrounded by LED lamps. The volume of the reactor without beads is 2.4 L, and with beads, 0.8 L. The photocatalytic efficiency of the reactor was evaluated by observing the degradation of Plasmocorinth B pollutant and selected pharmaceuticals (ibuprofen, sulfamethoxazole and diclofenac) at different flow rates under illumination of varying number of lights in deionized water and ISO medium. CFD simulations were performed to analyze the velocity and radiation field. The relationship between mass transfer and reaction kinetics was quantitatively evaluated by calculating the Peclet number, Damköhler number, and mass transfer coefficients. Total organic carbon (TOC) was also measured in the resulting solutions to determine the rate of mineralization. The toxicity tests were performed by exposing the solutions to the planktonic crustacean Daphnia magna for 48 h. The results showed that the number of lights directly and the flow rate inversely affected the degradation of the parent compound. At lower flow rates, total degradation of 87–97 % of the contaminants was observed in one flow and halving the light intensity resulted in a 10–15 % decrease in overall degradation. The toxicity tests showed that toxic transformation products were formed and were present until the complete degradation of the parent compound, after which they were also degraded. This study shows that the continuous flow photoreactor presents a potential solution for large-scale wastewater treatment.

Fluence-Dependent Photoinduced Charge Transfer Dynamics in Polymer-Wrapped Semiconducting Single-Walled Carbon Nanotubes.

Because an individual single-walled carbon nanotube (SWNT) can absorb multiple photons, the exciton density within a single tube depends upon excitation conditions. In SWNT-based energy conversion systems, interactions between excitons and charges make it possible for multiple types of charge transfer reactions. We exploit a SWNT-molecular donor-acceptor hybrid system (R-PBN(b)-Ph6-PDI-[(6,5) SWNT]) that fixes spatial organization and stoichiometry of perylene diimide (PDI) electron acceptors on the nanotube surface, to elucidate how excitation fluence affects ultrafast charge separation (CS) and the nature of charge recombination (CR) dynamics triggered upon SWNT near-infrared excitation. Pump-probe data characterizing these photoinduced CS and thermal CR reactions were acquired over excitation fluences that produce ∼5-125 excitons per 700 nm long nanotube. These experiments show that optical excitation gives rise to CS states in which PDI radical anions (PDI-•) and SWNT hole polarons (SWNT•+) have geminate and nongeminate spatial relationships. Under low excitation fluences, the observed dynamics reflect CR reactions of these geminate and nongeminate CS states. As excitation fluence increases, persistent excitons, which have not undergone CS, undergo reaction with ([SWNT(•+)n]-(PDI-•)n) CS states to produce lower-energy CS states that are characterized by hole (SWNT•+) and electron (SWNT•-) polarons. When nongeminate SWNT•+ and SWNT•- charge carriers are generated, CR dynamics depend on the time scale required for these oppositely charged solvated SWNT polarons to encounter each other. Because SWNT excitons have substantial excited-state reduction (1E-/*) and excited-state oxidation (1E*/+) potentials, they can drive additional charge transfer reactions involving initially prepared CS states under experimental conditions where excess excitons are present.

Phase Engineering of ZnSe by Small Molecules as a High-Performance Protective Layer for Zn Anode.

The practical application of aqueous zinc ion batteries is still hampered by the side reactions and dendrite growth on Zn anode. Herein, the phase engineering of ZnSe coating layer by incorporating small molecules is developed to enhance the performance of Zn anode. The unique electronic structure of ZnSe⋅0.5N2H4 promises strong adsorption for Zn atoms and enhanced ability to inhibit hydrogen evolution, thereby promoting uniform Zn deposition and preventing by-product and dendrite growth. Meanwhile, fast Zn2+ transfer and deposition kinetics are also demonstrated by ZnSe⋅0.5N2H4. As a result, the ZnSe⋅0.5N2H4@Zn symmetric cell achieves long-term cycling stability up to 1900 h and 300 h at high current densities of 5 mA cm-2 and 20 mA cm-2, respectively. The assembled ZnSe⋅0.5N2H4@Zn||NH4V4O10 full cell presents outstanding cycling stability and rate capability. This work highlights the key role of crystal phase control of protective layer for high-performance zinc anode.

Investigating the role of internal electric fields on interfacial charge transfer dynamics in 2D MoSTe/WSeTe heterojunction for photocatalytic water splitting

Introducing the degrees of freedom brought by intrinsic dipole moments into heterojunctions allows for effective manipulation through the combination of different interfaces, thus offering more possibilities for designing high-performance photocatalysts. The influence of internal electric fields (EIN) in Janus materials on heterojunction interface charges is a crucial aspect of understanding the intrinsic mechanisms of charge transfer at interfaces. To address this, we construct four contact modes of MoSTe/WSeTe heterojunctions, considering the work function difference as a mediator to quantify two different electric fields. It is estimated that the influence of the interfacial electric field (EIF) on interfacial charge transfer is approximately 1.6 times that of the EIN (pointing outwards the interface). Moreover, the direction of the EIN varies, resulting in different impacts on interface charges. Subsequently, we also discuss the conditions under which different charge transfer modes are formed at different contact surfaces. On the other hand, the heterojunction of the Te-S mode can serve as a direct Z-Scheme photocatalyst for overall water splitting, and the presence of vacancies is necessary to address the issue of surface passivation. Our study not only refines the intrinsic mechanism of interfacial charge transfer in Janus-based heterojunctions but also predicts a direct Z-Scheme photocatalyst capable of achieving overall water splitting.

Electrochemical Determination of Tinidazole and Brucine Using Poly (l‐Glutamic Acid) Modified Carbon Nanotube Paste Electrode

AbstractThis study developed an electrochemical method for the selective and sensitive detection of Tinidazole (TZ) by modifying a bare carbon nanotube paste electrode (BCNTPE) with electrochemically polymerized l‐Glutamic acid (P(L‐GA)/MCNTPE). The modified carbon nanotube paste electrode (MCNTPE) achieved optimal detection with an irreversible peak in a 0.2 M phosphate buffer solution (PBS) at pH 3.5. Characterization of both the P(L‐GA)/MCNTPE and BCNTPE was carried out using techniques such as scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and linear sweep voltammetry (LSV). The sensor effectively identified possible interferences from different metals and organic compounds, with scan rate studies indicating that the reaction was controlled by diffusion. The effects of pH and concentration variations were also thoroughly investigated. The active surface area of the P(l‐GA)/MCNTPE and BCNTPE were found to be 0.471 cm2 and 0.217 cm2 respectively. The P(l‐GA)/MCNTPE displayed excellent electrochemical properties, with a limit of detection (LOD) of 0.06 µM and a limit of quantification (LOQ) of 0.2 µM, along with good reproducibility, repeatability, and stability. This study presents a P(l‐GA) MCNTPE that significantly enhances the sensitivity and selectivity for simultaneous detection of TZ and bare carbon nanotube (BCN). The improved electroactive surface area and electron transfer dynamics demonstrate its potential for practical applications in pharmaceutical analysis.

Currency power as a medium: Revisiting international cost transfer mechanisms in the U.S. subprime crisis

This paper endeavors to meticulously examine the disparities in developmental trajectories between industrialized and emerging economies, employing the nuanced concept of cost transfer within the theoretical framework of the "core-periphery" paradigm. We propose an intricate conceptual model to delve into the mechanisms through which economic crises are systematically shifted from the developed core to the peripheral developing regions, with particular emphasis on the pivotal roles of monetary hegemony and geopolitical dominance. Utilizing the U.S. subprime mortgage crisis as a seminal case study, we scrutinize the intricate dynamics of cost transfer, elucidating how the developed nations leverage their monetary supremacy and geopolitical prowess, often bolstered by military might and neo-liberal ideologies, to facilitate the offloading of inflationary pressures and commodity price hikes onto developing nations, notably China. Our findings contribute to the ongoing discourse on the entrenched inequalities between the Global North and South, emphasizing the asymmetrical power relations that underpin the process of cost transfer. Furthermore, this study enhances the research framework of cost-transfer theory and offers insights into the development of inequalities between developed and developing countries, aiding in the formulation of response strategies for developing countries facing cost transfer and mitigating the adverse impacts of cost transfers, thereby fostering more equitable and sustainable development trajectories.

Accelerating Small Electron Polaron Dissociation and Hole Transfer at Solid-Liquid Interface for Enhanced Heterogeneous Photoreaction.

In a photocatalysis process, quick charge recombination induced by small electron polarons in a photocatalyst and sluggish kinetics of hole transfer at the solid-liquid interface have greatly limited photocatalytic efficiency. Herein, we demonstrate hydrated transition metal ions as mediators that can simultaneously accelerate small electron polaron dissociation (via metal ion reduction) and hole transfer (through high-valence metal production) at the solid-liquid interface for improved photocatalytic pollutant degradation. Fe3+, by virtue of its excellent redox ability as a homogeneous mediator, enables the BiVO4 photocatalyst to achieve drastically increased photocatalytic degradation performance, up to 684 times that without Fe3+. The enhanced performance results from Fe(IV) species production (via Fe3+ oxidation) induced by dissociation of small electron polarons (via Fe3+ reduction), featuring an extremely low kinetic barrier (5.4 kJ mol-1) for oxygen atom transfer thanks to the donor-acceptor orbital interaction between Fe(IV) and organic pollutants. This work constructs a high-efficiency artificial photosynthetic system through synergistically eliminating electron localization and breaking hole transfer limitation at the solid-liquid interface for constructing high-efficiency artificial photosynthetic systems.

Z-Scheme BiVO4/g-C3N4 Photocatalyst-With or Without an Electron Mediator?

The hybrid system BiVO4/g-C3N4 is a prospective photocatalyst because of the favorable mutual alignment of the energy bands of both semiconductors. However, the path of the photocatalytic process is still unclear because of contradictory information in the literature on whether the mechanism of charge carrier separation at the BiVO4/g-C3N4 interface is band-to-band or Z-scheme. In this work, we clarified this issue by comparative photocatalytic studies with the use of systems without a mediator and with different kinds of mediators including Au nanoparticles, fullerene derivatives, and the Fe3+/Fe2+ redox couple. Additionally, the charge transfer dynamics at the BiVO4/g-C3N4 and BiVO4/mediator/g-C3N4 interfaces were investigated by time-resolved photoluminescence (TRPL) measurements, while the influence of the mediator on the surface recombination of the charge carriers was verified by intensity-modulated photocurrent spectroscopy (IMPS). We proved that the charge carrier separation at the BiVO4/g-C3N4 interface occurs according to the mechanism typical for a heterojunction of type II, while the incorporation of the mediator between BiVO4 and g-C3N4 leads to the Z-scheme mechanism. Moreover, a very strong synergetic effect on caffeine (CAF) degradation rate was found for the system BiVO4/Au/g-C3N4 in the presence of Fe3+ ions in the CAF solution.

Exploring Charge Transfer Mechanisms in Schiff Base‐Modified N‐Doped GQDs: Insights from DFT and Pump‐Probe Spectroscopy for Bioimaging Applications

AbstractIn recent developments, graphene quantum dots (GQDs) have emerged as valuable tools for imaging and biosensing. Various modifications on the GQDs with any desired functionality and attachment of organic molecules and/or nanostructures allow tuning their photophysical properties as well as charge transfer dynamics for bioimaging applications. This study focuses on synthesizing and characterizing of polyethyleneimine‐functionalized nitrogen‐doped GQDs (NC1), Schiff base‐ functionalized nitrogen‐doped GQDs (NC2), and silver nanocomposites of these Schiff base‐functionalized nitrogen‐doped GQDs (NC3). We explore their absorption and emission properties to understand their interactions in the ground state. Furthermore, ultrafast transient absorption spectroscopy measurements reveal that the presence of NC3 shortens the excited state lifetime of NC1 due to charge transfer, resulting in reduced fluorescence intensity. Both experimental and DFT results suggest the potential of NC3 for bioimaging and sensing applications, making them promising candidates for phototheranostic purposes.

Adsorption of thiotepa on B12N12, Mg12O12, and Si12C12 fullerene-like cages: A DFT study

We examined the adsorption of thiotepa (TTP) on the outer surface of B12N12, Mg12O12, and Si12C12 fullerene-like cages using density functional theory (DFT) calculations. The computations were carried out at the Perdew-Burke-Ernzerhof level with the D3 dispersion correction (PBE-D3) in a water solvent. The adsorption mechanism of TTP through N-head and S-head on the external surface of Si12C12 involves a covalent interaction (binding energy ∼ −1.31 eV) with the carrier surface. In contrast, the adsorption of the TTP molecule through N-head and S-head on the outer surfaces of B12N12 (binding energy ∼ −0.75 eV) and Mg12O12 (binding energy ∼ −0.62 eV) fullerene-like cages is driven by electrostatic interactions. Therefore, due to their low values of recovery time, both B12N12 and Mg12O12 fullerene-like cages can serve as carriers for TTP in the treatment of cancer. Thermodynamic parameters (Gibbs free energy and enthalpy energy) demonstrate that these interactions are exothermic and spontaneous. The results further reveal the significant disparity in the calculated HOMO and LUMO energies at the computational level. The formation of intricate bonds between the drug and the fullerene-like cages is attributed to the charge transfer dynamics that occur during their interactions. Through computational analysis and examination of the total density of state (TDOS) plots, it is evident that B12N12 and Si12C12 fullerene-like cages exhibit a high degree of sensitivity to the TTP drug. The adsorption process can increase the electrical conductivity of B12N12 and Si12C12, while having minimal effect on Mg12O12. This suggests that B12N12 could potentially serve as a suitable biosensor for detecting TTP.

Kinetics of electromigration mass transfer in micro- and nanoelectronics interface elements depending on the strength of thin-film junctions

The theoretical model proposed earlier by the authors, which describes the interrelation of strength and electromigration (diffusion) properties of interfaces formed by joined materials, has been perfected and extended. Within the framework of the developed model, a linear relationship between the values of the work of reversible interface separation Wa and the activation energy of electromigration in the interface HEM was established. The coefficients of the obtained relation are estimated and compared with experimental data on the study of electromigration in a copper conductors covered with protective dielectrics. Using also the model developed earlier by the authors, which describes the dependence of the value on the concentrations of non-equilibrium lattice defects in the volumes of joined materials, a number of effects due to the influence of such defects on the processes caused by electromigration have been predicted and investigated. In the paper we obtained that by introducing non-equilibrium lattice defects in the volumes of bonded materials in the form of atomic impurities of interstition or substitution it is possible to effectively influence the characteristics of electromigration instability of the shape of the interlayer interface. For the introduction impurities, quantitative analytical estimates of the impurity concentration necessary for a significant change (both increase and decrease) in the characteristic rise time of the instability of the shape of the initially flat interface have been obtained.

Redox Properties of Structural Fe in Clay Minerals: 4. Reinterpreting Redox Curves by Accounting for Electron Transfer and Structural Rearrangement Kinetics.

Iron-bearing smectite clay minerals can act as electron sources and sinks in the environment. Previous studies using mediated electrochemical analyses to determine the reduction potential (EH) values of smectites observed that the relationship between the structural Fe2+(s)/FeTotal ratio in the smectite and EH varied based on the redox history of the smectite. We hypothesize that this behavior, referred to as redox hysteresis, results from the smectite particles not equilibrating with the applied EH over the course of the experiment (∼30 min). To test this hypothesis, we developed a model incorporating interfacial electron transfer kinetics and charge redistribution within the particle to simulate the mediated electrochemical experiments from previous studies. The simulated redox curves accurately matched the previously reported experimental redox curves of the smectite SWa-1, demonstrating that longer equilibration periods led to a decrease in redox hysteresis. We validated this experimentally by measuring the redox curve of SWa-1 after an equilibration period of at least 12 h. Furthermore, we extended the simulations to three other smectites (NAu-1, NAu-2, and SWy-2) and extracted their respective thermodynamic and kinetic parameters. This work offers a framework for interpreting and modeling redox reactions on clay surfaces, along with key parameters for four commonly studied smectites.

Real Case Study of 600 m3 Bubble Column Fermentations: Spatially Resolved Simulations Unveil Optimization Potentials for l-Phenylalanine Production With Escherichia coli.

Large-scale fermentations (»100 m³) often encounter concentration gradients which may significantly affect microbial activities and production performance. Reliably investigating such scenarios in silico would allow to optimize bioproduction. But related simulations are very rare in particular for large bubble columns. Here, we pioneer the spatially resolved investigation of a 600 m³ bubble column operating for Escherichia coli based l-phenylalanine fed-batch production. Microbial kinetics are derived from experimental data. Advanced Euler-Lagrange (EL) computational fluid dynamics (CFD) simulations are applied to track individual bubble dynamics that result from a recently developed bubble breakage model. Thereon, the complex nonlinear characteristics of hydrodynamics, mass transfer, and microbial activities are simulated for large scale and compared with real data. As a key characteristic, zones for upriser, downcomer, and circulation cells were identified that dominate mixing and mass transfer. This results in complex gradients of glucose, dissolved oxygen, and microbial rates dividing the bioreactor into sections. Consequently, alternate feed designs are evaluated splitting real feed rates in two feeds at different locations. The opposite reversed installation of feed spots and spargers improved the product synthesis by 6.24% while alternate scenarios increased the growth rate by 11.05%. The results demonstrate how sophisticated, spatially resolved simulations of hydrodynamics, mass transfer, and microbial kinetics help to optimize bioreactors in silico.

Elucidating the Photo-Induced Electronic Structure and Mechanisms of ZnAl-Layered Double Hydroxides: A DFT Study.

Layered double hydroxides (LDHs) have been regarded as excellent catalysts for a variety of photocatalytic applications including the hydrogen production, carbon dioxide reduction, and nitrogen fixation, etal. The elucidation of the photocatalytic mechanism of LDH-based photocatalysts under light irradiation, especially at the ultraviolet (UV) and deep ultraviolet (DUV) region, at the molecular level has remained elusive. In this study, the photo-induced electronic structure of ZnAl-LDH materials were investigated, and a comprehensive understanding of its underlying mechanism, both in the UV and DUV region, was gained using density functional theory (DFT) calculations. The UV and DUV regions exhibit distinct excitation characteristics, revealing the complex interactions between electrons and holes within the system. The DUV region significantly promotes electron transfer, indicating the potential application of LDH materials as a DUV catalysis material. This study elucidates the electron transfer kinetics in LDHs upon UV and DUV irradiation, thereby offering new perspective for the development of photocatalytic materials under different light region.

Development of Semi-Empirical and Machine Learning Models for Photoelectrochemical Cells

We introduce a theoretical model for the photocurrent-voltage (I-V) characteristics designed to elucidate the interfacial phenomena in photoelectrochemical cells (PECs). This model investigates the sources of voltage losses and the distribution of photocurrent across the semiconductor–electrolyte interface (SEI). It calculates the whole exchange current parameter to derive cell polarization data at the SEI and visualizes the potential drop across n-type cells. The I-V model’s simulation outcomes are utilized to distinguish between the impacts of bulk recombination and space charge region (SCR) recombination within semiconductor cells. Furthermore, we develop an advanced deep neural network model to analyze the electron–hole transfer dynamics using the I-V characteristic curve. The model’s robustness is evaluated and validated with real-time experimental data, demonstrating a high degree of concordance with observed results.