Electron Transfer Properties Research Articles

Exploring Metal- and Porphyrin-Modified TiO2-Based Photocatalysts for Efficient and Sustainable Hydrogen Production

Photocatalytic H2 production is one of the most promising approaches for sustainable energy. The literature presents a plethora of carefully designed systems aimed at harnessing solar energy and converting it into chemical energy. However, the main drawback of the reported photocatalysts is their stability. Thus, the development of a cost-effective and stable photocatalyst, suitable for real-world applications remains a challenge. An ideal photocatalyst for H2 production must possess appropriate band-edge energy positions, an effective sacrificial agent, and a suitable cocatalyst. Among the various photocatalysts studied, TiO2 stands out due to its stability, abundance, and non-toxicity. However, its efficiency in the visible spectrum is limited by its wide bandgap. Metal doping is an effective strategy to enhance electron–hole separation and improve light absorption efficiency, thereby boosting H2 synthesis. Common metal cocatalysts used as TiO2 dopants include platinum (Pt), gold (Au), copper (Cu), nickel (Ni), cobalt (Co), ruthenium (Ru), iron (Fe), and silver (Ag), as well as bimetallic combinations such as Ni-Fe, Ni-Cu, Nb-Ta, and Ni-Pt. In all cases, doped TiO2 exhibits higher H2 production performance compared to undoped TiO2, as metals provide additional reaction sites and enhance charge separation. The use of bimetallic dopants further optimizes the hydrogen evolution reaction. Additionally, porphyrins, with their strong visible light absorption and efficient electron transfer properties, have demonstrated potential in TiO2 photocatalysis. Their incorporation expands the photocatalyst’s light absorption range into the visible spectrum, enhancing H2 production efficiency. This review paper explores the principles and advancements in metal- and porphyrin-doped TiO2 photocatalysts, highlighting their potential for sustainable hydrogen production.

Enzyme-Mimic Activities of RuCo Bimetallic Nanosheets for Inflammatory Bowel Disease Treatment.

The presence of abnormal levels of reactive oxygen species (ROS) is a recognized pathological feature of inflammatory bowel disease (IBD). Therefore, the development of orally administered antioxidants with high antioxidative capacity and gastric acid tolerance for the treatment of IBD is of great significance. Here, we present the design and synthesis of a bimetallic ruthenium-cobalt (RuCo) nanosheet for the treatment of IBD. The Ru-Co atoms within the nanosheet structure exhibit significant electron transfer properties owing to their electronegativity feature. Density functional theory calculations indicate that the RuCo nanosheets have higher d-band centers than the corresponding Ru and Co metal monoliths, which increases the catalytic activity. Such RuCo nanosheets exhibit superoxide dismutase and catalase-like cascade enzyme activities and show robust stability in gastric fluid over a 4 h period when exposed to simulated gastric fluid, ensuring desirable retention of antioxidative activity. Cellular and animal studies show that RuCo nanosheets are capable of effectively reducing oxidative stress, preventing inflammatory responses triggered by an abnormal increase in ROS at intestinal sites, and thus protecting cells from inflammatory damages. This research presents a gastric-acid-stabilized antioxidative nanocatalytic platform for the efficient treatment of inflammatory diseases of the digestive system.

Bimetallic Fe-Mo modified N-doped carbon materials activating peroxymonosulfate for acetaminophen degradation: Synergistic effects of free radicals and electron transfer process.

Bimetallic Fe-Mo modified N-doped carbon materials activating peroxymonosulfate for acetaminophen degradation: Synergistic effects of free radicals and electron transfer process.

Dual Z-scheme black phosphorus quantum dots (BPQDs)/ Cu2O crystalline/amorphous Ti, Fe-layered double hydroxides (LDH) heterojunction construction with enhanced electron transfer property for photocatalytic nitrogen fixation

Dual Z-scheme black phosphorus quantum dots (BPQDs)/ Cu2O crystalline/amorphous Ti, Fe-layered double hydroxides (LDH) heterojunction construction with enhanced electron transfer property for photocatalytic nitrogen fixation

Controlling outer-sphere solvent reorganization energy to turn on or off the function of artificial metalloenzymes

Metalloenzymes play essential roles in biology. However, unraveling how outer-sphere interactions can be predictably controlled to influence their functions remains a significant challenge. Inspired by Cu enzymes, we demonstrate how variations in the primary, secondary, and outer coordination-sphere interactions of de novo designed artificial copper proteins (ArCuPs) within trimeric (3SCC) and tetrameric (4SCC) self-assemblies—featuring a trigonal Cu(His)3 and a square pyramidal Cu(His)4(OH2) coordination—influence their catalytic and electron transfer properties. While 3SCC electrocatalyzes C-H oxidation, 4SCC does not. CuI-3SCC reacts more rapidly with H2O2 than O2, whereas 4SCC is less active. Electron transfer, reorganization energies, and extended H2O-mediated hydrogen bonding patterns provide insights into the observed reactivity differences. The inactivity of 4SCC is attributed to a significant solvent reorganization energy barrier mediated by a specific His---Glu hydrogen bond. When this hydrogen bond is disrupted, the solvent reorganization energy is reduced, and C-H peroxidation activity is restored.

Lattice Distortion Broadens the eg Band of Co3O4 to Facilitate p-d Hybridization for Enhanced Electrochemical Nitrate Synthesis.

The electrochemical nitrogen oxidation reaction (NOR) presents a sustainable pathway for nitrate synthesis under mild conditions; however, the process is hindered by the inadequate adsorption and activation of N2 on electrocatalysts. In this study, we utilized Co3O4 as a model catalyst and engineered lattice distortions by introducing oxygen vacancies, which expanded the eg band of the active sites to enhance N2 activation. The modified Co3O4 catalyst achieved a Faradaic efficiency of 10.68% and a nitrate yield of 58.80 μg·h-1·mgcat-1. Comprehensive experimental and density functional theory (DFT) analyses demonstrated that these modifications resulted in a shortened Co-N bond length and an elongated N≡N bond, leading to improved p-d hybridization between N2 and Co sites. Moreover, the enhancements in catalytic performance were also attributed to the improved electron transfer properties stemming from the altered band structure of Co3O4. This work provides innovative design principles for catalysts aimed at facilitating complex electrocatalytic reactions with multiple kinetics.

Increased removal of ginsenoside Rb1 through the application of capacitance-enhanced biochars in soils

Accumulation of allelochemicals in agricultural soils results in severe obstacles to continuous cropping and poses a notable challenge to global food security. The ginsenosides released into the rhizosphere soil as root secretion or during the degradation of plant residues exhibit autotoxic effects to plants and facilitate the proliferation of root rot bacteria. This study proposes that biochar can be used to alter the electron transfer processes in soil to create a unique “charosphere”, which is beneficial for ginsenoside Rb1 removal in soils planted with Panax notoginseng. Biochars were also intentionally modified to enhance their electron transfer properties in charosphere soil. The introduction of biochars activated electro-nutrient microorganisms such as Lactobacillus, Pseudomonas and Klebsiella. However, the abundance of major pathogens of Panax notoginseng, including Fusarium spp., Alternaria, and Sarocladium was reduced by 3.77%–4.79% in Soil-2 and 9.08–17.18% in Soil-3 after applying modified biochars by KHB4 in soils with different years of planting P. notoginseng. Modified biochar also exhibited superior effectiveness in promoting ginsenoside Rb1 chemisorption and biodegradation, and enhancing microbial community diversity, compared to unmodified biochar. This was attributed to the electron-rich (orbital) high-energy alkyne bonds introduced by KHB4 modification, which improved the capacitance values of the biochar by 14.62–316.2 μF/cm2. Meanwhile, KBH4-modification reduces the diffusion impedance layer on biochar surface and the charge transfer resistance inside the biochar matrix. The chemical structures containing π-electron may be the dominant biochar composition to stimulate the growth of electro-nutrient microorganisms and accelerate ginsenoside Rb1 degradation. Our study suggests that alterations in electron transfer processes within the charosphere through the application of biochar regulate the microbiome community structure in the soil. This regulation has the potential to mitigate continuous-cropping disorders in agricultural soils.

Ti-MXene/α-Ni(OH)2 Nanostructures as High-Performance Electrocatalyst for Oxygen Evolution Reaction.

Herein, the strategy of homogenous inclusion of nanoparticles within the surface and interlayers of 2D MXenes is established to achieve effective oxygen evolution reaction (OER) performance. A greater quantity of nano-sized Ni(OH)2 particles is uniformly anchored on multilayered accordion-like nanosheets of Ti3C2Tx. The strong interconnection of Ni(OH)2 on Ti3C2Tx promotes synergistic effects and improves electron transfer properties alongside the intrinsic OER activity. The Ti3C2Tx-Ni(OH)2-4 demonstrates remarkable OER activity by exhibiting a lower overpotential (235.54 mV at 10 mA cm-2) in alkaline conditions. Increased electrochemical active surface area (2.925 mF cm-2), lower charge transfer resistance, lowering the reaction barrier, and stabilizing/converting essential intermediates via the Ti3C2Tx-Ni(OH)2 electrocatalyst synergistically improve OER activity. The effective interaction between Ti3C2Tx and Ni(OH)2 in Ti3C2Tx-Ni(OH)2 improves stability during long-term operations. Moreover, a Ti3C2Tx-Ni(OH)2-4||Pt/C cell has 1.7V at 10 mA cm-1 . It can be deduced that the usage of Ni(OH)2 as an electrocatalyst together with Ti3C2Tx can provide noteworthy water-splitting properties.

Strategic Design of Fluorescent Perylene-Modified Nucleic Acid Monomers: Position-, Phosphorylation-, and Linker-Dependent Control of Electron Transfer.

Synthetic fluorescent nucleotides (SFNs) have a wide variety of applications in biochemical tracking, imaging, and diagnostic assays. There are many SFNs in active development to enhance their fluorescence wavelengths, environmental sensitivity, photostability, and photochemical/photoswitchable properties. However, there are few systematic theoretical studies of their fluorescence properties. In this work, we apply excited-state QM/MM dynamics with TDDFT to nucleic acids tagged with perylene, which is particularly photostable, fluorescent, and bright (fluorescence quantum yield = 0.94) in isolation. We demonstrate that the overall structure, phosphorylation state, and linker type control electron transfer and fluorescence properties. A critical 90° dihedral angle between the perylene tag and nucleobase drives rapid quenching through charge transfer pathways, with positions 7 and 8 on guanine showing higher quenching propensity than position 2. Potential energy profiles reveal that the accessibility of the 90° base-tag geometries is critical for charge transfer, with the attachment position controlling this accessibility through steric and electronic effects. The presence of a phosphate group modulates this process by stabilizing excited states and reducing charge transfer rates. Additionally, ethynylene linkers maintain fluorescence through reduced angular dependence. The directionality of electron transfer stems primarily from the nucleic acid type, with guanine showing bidirectional transfer depending on the initial geometry, while adenine remains stable without significant charge transfer. These findings provide structural design principles for improved synthetic fluorescent nucleotides with tailored charge transfer characteristics.

Direct Cyclization of 1,3-Diketones with Malonate-Based Iodonium Ylides to Generate Dihydrofurans.

While iodonium ylides are important reantants in a wide range of reactions, the exploration of electron-transfer property of iodonium ylides remains an underdeveloped topic. Herein, we describe a direct cyclization of 1,3-diketones with malonate-based iodonium ylides to give a diverse array of dihydrofurans in moderate yields. The control experiments suggest that the electron transfer between enol and iodonium ylide gives reactive species, thus enabling a cyclization cascade process to take place to give dihydrofurans.

Advanced synthesis, comprehensive characterization, and potent cytotoxicity of 2,6-Bis(2-aminophenylimino)methyl)-4-methoxyphenol and its binuclear copper(II) complex

The imine base and Cu2+ precursors were combined using magnetic stirring to formulate the Cu2+ complexes. The formation of the imine base was confirmed by electronic and vibrational spectra, proton NMR, LC-mass spectrometry, and computational studies, which also optimized the final structure. The Cu2+ complexes were characterized using electronic and vibrational spectra, magnetic susceptibility, molar conductivity, a variable temperature magnetometer, and ESR spectroscopy. Cyclic voltammetry revealed electron transfer from Cu2+ to Cu+ within the complex. The in vitro tumour activity of the Cu2+ complexes and imine base were evaluated on the A431 cell line using the MTT assay. DFT studies validated the structural stability of the imine base. The antiferromagnetic behaviour observed at low temperatures suggests that these Cu2+ complexes could be useful in heavy magnetic materials. Due to their electron transfer properties, Cu2+ complexes also hold potential for use in electroplating systems and sensors. The complexes exhibited high efficacy on the cell line, aligning with clinical objectives. The Cu2+ complexes are represented as [MLR], where M is the metal, L is the imine base, and R = [C₆H₅COO] or R = [C₆H₄COO(NH₂)].

ELECTROCHEMICAL CHARACTERIZATION OF NON-ENZYMATIC GLUCOSE BIOSENSOR BASED ON SILVER NANOPARTICLE (AgNPs) STABILIZED WITH SODIUM TRIPOLYPHOSPHATE (NaTPP) CROSS-LINKED CHITOSAN.

The development of non-enzymatic glucose biosensor has garnered significant attention the recent research. This interest arises primarily from the limitations associated with enzyme-based sensors, which, despite their remarkable sensitivity and selectivity, face challenges such as inadequate stability, complex enzyme immobilization process, and stringent operational conditions including optimal temperature, and issues with reproducibility. This study presents a cost-effective and biocompatible non-enzymatic glucose biosensor utilizing silver nanoparticles (AgNPs) stabilized with sodium tripolyphosphate (NaTTP) cross-linked chitosan. The AgNPs were synthesized and characterized using Fourier transform infrared spectroscopy (FTIR), X-ray Diffractometry (XRD), and Scanning electron Microscopy (SEM). XRD analysis revealed the crystalline size of the AgNPs, while the SEM images indicated a spherical morphology with a non-uniform granular structure, which can be attributed to the bio mediated ionic gelation process. The FTIR spectrum displayed peaks between 1054-1645 cm-1, indicating the formation of phosphonate bond between the –NH3+ groups of chitosan and the –PO32- moieties of NaTTP during cross-linking process. The direct electron transfer and electro-catalytic properties of the AgNPs modified glassy carbon electrode (AgNPGCE) were examined through Potentiometric methods. The electro-catlytic oxidation of glucose at the AgNPGCE surface, along with the underlying mechanism of glucose oxidation, was elucidated through cyclic voltammetry. The AgNPGCE demonstrated superior electrochemical performance in response to glucose, exhibiting high sensitivity at +0.54 V.

Naphthalenediimide-Based Hybrid Material with Eu-Substituted Polyoxometalate: Photochromism, Near-Infrared Photothermal Conversion, and C-3 Functionalization of Indoles.

Designing and developing novel photochromic materials with additional functions such as photothermal conversion and photocatalysis are challenging but meaningful objectives. Crystalline naphthalenediimide (NDI)-based hybrids are an attractive class of multifunctional materials with fast-response photoinduced electron transfer and charge separation properties. They are promising photothermal conversion materials and photocatalysts. Herein, a novel hybrid material, EuPMo11O39(L)1.5(H2O)2]·DMA (EuMo-NDI) (L = N,N'-di(1-oxido-4-pyridyl)-1,4,5,8-naphthalenediimide), was prepared with a solvothermal method, integrating a photoactive NDI derivative and an Eu-substituted polyoxometalate. EuMo-NDI exhibits 0D structure with sensitive photochromic behavior under UV-vis light irradiation due to fast-response photoinduced electron transfer between its components. The colored EuMo-NDI sample demonstrated efficient near-infrared photothermal conversion due to the strong absorption of the photogenerated radical anion NDI•- and mixed valence heteropoly blue in the near-infrared region. Meanwhile, EuMo-NDI is easily excited in the presence of electron donors to form the radical species, which can activate inert O2 to superoxide radical O2•-. EuMo-NDI exhibited high photocatalytic activity for C-3 thiocyanation of indoles under mild conditions using white light as a driving force. This work provides an effective avenue to design novel photothermal conversion materials and photocatalysts using photochromic materials as platforms.

Phenol formaldehyde‐flax fabric (PF‐F) hybrid composites reinforced with cellulose nanofiber (CNF)—mechanical, morphology, electrical conductivity, electronic structure, optoelectronic, and charge transfer properties

AbstractFor developing an eco‐friendly world, a sustainable solution has encouraged to use natural fibers. Among the various options, lignocellulose fiber‐reinforced composites have captured the interest of material experts and engineers. These remarkable materials offer plentiful supply, inherent sustainability, easily degradability, and affordability, making them an attractive choice for a multitude of uses. Herein, we prepared a series of hybrid cellulose nanofiber (CNF)‐reinforced phenolic composites. Flax fabric was coated with CNF followed by phenolic resin coating was made in this work to check the mechanical, morphological behavior, electrical conductivity, electronic structure, opto‐electronic, and charge transfer properties. We found that 0.5 CNF showed better tensile properties, greater AC conductivity, dielectric constant, and dielectric loss compared with other composites. The electronic structure, opto‐electronic, and charge transfer properties of the PF‐resin/nanocellulose polymer nanocomposite have been systematically examined using density functional theory (DFT). The findings indicate that the PF‐resin/cellulose nanocomposite undergoes intramolecular charge transfer (CT) in response to an external electric field. The negative binding energy exhibited between the DFT optimized PF‐resin/cellulose nanocomposite shows the complex is stable and energy‐favorable.Highlights The impact of CNF on the properties PF‐F hybrid composites was investigated. The mechanical performance has been improved by the addition of CNF. The incorporation of CNF improved the fracture toughness of the composites. The fabricated composite has negative binding energy from DFT studies. A promising high‐performance electroactive polymer and structural material.

The role of sulfidated zero-valent iron in enhancing anaerobic digestion of waste activated sludge.

The role of sulfidated zero-valent iron in enhancing anaerobic digestion of waste activated sludge.

Novel Fullerene-Based Dyes for Solar Cells Applications: Insights from Density Functional Theory and Time Dependent Density Functional Theory Investigations

Fullerene-based organic dyes hold significant promise for advancingsolar cell technologies due to their exceptional optoelectronic properties. This study investigates two novel fullerene-based dyes, Fullerene Dye 1 and Fullerene Dye 2 (FD1 and FD2), using Density Functional Theory (DFT)and Time-Dependent Density Functional Theory(TD-DFT)to evaluate their potential for solar cell applications. The electronic properties, including the Highest Occupied Molecular Orbital (HOMO), Lowest Unoccupied Molecular Orbital (LUMO), and HOMO-LUMO (H-L) energy gaps, were analyzed using the B3LYP functional with a 6-31G basis set, incorporating solvation effects with dichloromethane (DCM) in the Polarizable Continuum Model (PCM). FD1 exhibited a HOMO of -5.123 eV, a LUMO of -3.458 eV, and an H-L gap of 1.665 eV, while FD2 showed a slightly larger gap of 1.807 eV with a HOMO of -5.261 eV and a LUMO of -3.454 eV. Time-dependent DFT analysis revealed maximum absorption wavelengths (𝜆max) of 997.10 nm and 995.16 nm for FD1 and FD2, respectively, with corresponding oscillator strengths of 0.0075 and 0.0048. The light-harvesting efficiencies, LHEs of FD1 and FD2 were 0.018 and 0.012, respectively. Both dyes demonstrated favorable reorganization energy, 𝜆=0.15eV, driving force for charge injection, Δ𝐺inj= 0.542eV for FD1 and 0.546 eV for FD2, and low driving force for charge recombination (Δ𝐺CR), indicating strong potential for efficient charge separation. These findings provide valuable insights into the electronic, optical, and charge transfer properties of fullerene-based dyes, with FD1 exhibiting a more balanced performance. The study highlights the potential of these dyes for enhancing the efficiencies of organic, dye-sensitized solar cells (DSSCs) and provides a foundation for future experimental validation and optimization.

Electrogenic dynamics of biofilm formation: Correlation between genetic expression and electrochemical activity in Bacillus subtilis.

Biofilms are structured microbial communities, known for their electron transfer properties, which are essential for metabolic processes and microbial survival. Here, we investigated the electrogenic properties of Bacillus subtilis, a bacterial producer of electron-donating biofilms. Interdigitated gold electrodes were utilized to continuously measure the electrochemical activity of biofilm-forming B. subtilis cells and genetic mutants unable to create them (biofilm-deficient). The formation of extracellular polymeric substances (EPS) and filamentous appendages was monitored via scanning electron microscopy (SEM). Chronoamperometry was used to assess electrochemical activity, which showed fluctuations in electrical current at specific time points in biofilm-forming cells. Cyclic voltammetry (CV) revealed significant differences between the voltammograms of biofilm-forming and biofilm-deficient cells, hypothesized to be a result of the reduction of secreted flavodoxin. Electrochemical impedance spectroscopy (EIS) was also performed at various intervals and analyzed using an equivalent circuit. We identified the presence of a charge transfer resistance (Rct) exclusively in biofilm which correlated to the time of increased electrochemical activity measured using chronoamperometry. Finally, through confocal microscopy, we found that the expression of a gene involved in biofilm matrix formation, tasA, was correlated with the time when charge transfer was measured. These results indicate that electrochemical activity is primarily present in biofilm-forming cells rather than in biofilm-deficient mutants. By combining electrochemical and microscopic methods, we developed a methodology to continuously monitor the stages of biofilm formation and showed that electrochemical activities within biofilms vary over time and there is a temporal relationship between these processes and the expression of genes responsible for biofilm development.

Creating Dual Active Sites in Ru-doped FeMn-MOF-74 for Efficient Overall Water Splitting.

The design of well-engineered bifunctional electrocatalysts is crucial for achieving durable and efficient performance in overall water splitting. In this study, Ru-doped FeMn-MOF-74 itself has Ru sites and generates FeMnOOH under catalytic conditions, forming dual active sites for overall water splitting. Density functional theory (DFT) calculations demonstrate that the Ru dopants exhibit optimized binding strength for H* and enhanced hydrogen evolution reaction (HER) performance. Moreover, the Mn sites within FeMnOOH lower the energy barrier for the rate-determining step (from O* to OOH*), serving as the active centre for oxygen evolution reaction (OER). The incorporation of Ru significantly improves the electron transfer properties of FeMn-MOF-74 and enhances its water adsorption capacity, synergistically boosting its bifunctional activity. This strategy of designing dual active sites provides new insights into the development of bifunctional metal-organic frameworks (MOFs) for efficient overall water splitting.

Synthesis of in-plane Mo2C/MoO3 heterostructures by a novel spatial-confined partial oxidation approach for enhanced TEA sensing.

In-plane heterostructures exhibit extraordinary chemical and electron transfer properties, which have received remarkable research attention. However, the synthesis of an in-plane Mo2C/MoO3 heterostructure has been rarely reported, and the deep investigation of the effect of its fine structure on reactivity is of great significance. Notably, the in-plane heterostructures endow the material with abundant grain boundaries, which facilitate the formation of surface acid sites and active oxygen species, thus contributing to the sensing performance. Our work provides a promising platform to design in-plane heterostructures for various advanced applications.

Optimizing Electronic and Photovoltaic Properties of D-π-A Organic Dyes for DSSCs Using Density Functional Theory.

This research utilizes density functional theory to investigate the ground and excited-state properties of a new series of organic dyes with D-π-A configurations (D1-D6) for their potential application in dye-sensitized solar cells. The study focuses on modifying these dyes using various functional groups as π-bridges to optimize their electronic properties and improve their efficiency as sensitizers in DSSCs. The frontier molecular orbitals (HOMO and LUMO) were analysed to evaluate electron transfer properties. The energy gaps, ranging from 2.449 to 2.6979eV, indicate favourable electron injection capabilities. Further analysis included molecular electrostatic potential, electron localization function, and localized orbital locator for all dyes. The maximum absorption wavelengths were found to range from 272.98nm to 624.76nm, covering both the UV and visible spectra. A significant redshift was observed with the addition of electron-withdrawing groups to the D-π-A structures, contributing to enhanced light-harvesting capabilities. The results indicate that all dyes exhibit improved open-circuit photovoltage, enhanced light-harvesting efficiency, and higher electron injection when compared to the reference dye (Dye1). Additionally, parameters such as oxidation potential, free energy change, redox potentials, electron transfer, and dye regeneration showed promising values, pointing to excellent photovoltaic efficiency. Electron injection from the dyes into the conduction band of TiO2, followed by efficient dye regeneration, was confirmed. The choice of the π-bridge group, in particular, plays a crucial role in optimizing dye performance. Based on the theoretical findings, all of the studied dyes demonstrate strong potential as effective photosensitizers for DSSCs applications.