Charge Transfer Mechanism Research Articles

Engineering an Ultrafast Ambient NO2 Gas Sensor Using Cotton-Modified LaFeO3/MXene Composites.

This work presents a room-temperature (RT) NO2 gas sensor based on cotton-modified LaFeO3 (CLFO) combined with MXene. LaFeO3 (LFO), CLFO, and CLFO/MXene composites were synthesized via a hydrothermal method. The fabricated sensor, utilizing MXene/CLFO, exhibits a p-type behavior and fully recoverable sensing capabilities for low concentrations of NO2, achieving a higher response of 14.2 times at 5 ppm. The sensor demonstrates excellent performance with a response time of 2.7 s and a recovery time of 6.2 s, along with notable stability. The sensor's sensitivity is attributed to gas interactions on the material's surface, adsorption energy, and charge-transfer mechanisms. Techniques such as in situ FTIR (Fourier transform infrared) spectroscopy, GC-MS (gas chromatography-mass spectroscopy), and near-ambient pressure X-ray photoelectron spectroscopy were employed to verify gas interactions and their byproducts. Additionally, finite-difference time-domain simulations were used to model the electromagnetic field distribution and provide insight into the interaction between NO2 molecules and the sensor surface at the nanoscale. A prototype wireless IoT (Internet of Things)-based NO2 gas leakage detection system was also developed, showcasing the sensor's practical application. This study offers valuable insight into the development of room-temperature NO2 sensors with a low detection limit.

Carboxylesterase 2-based fluorescent probe with large Stokes shift for differentiating colitis from bowel cancer

Colitis is considered a significant risk factor for the development and progression of colorectal cancer due to excessive inflammation formed as a result of inflammatory bowel disease (IBD), which is linked to colorectal cancer development. Colorectal cancer often lacks overt symptoms in its early stages, leading to late-stage diagnosis in most patients. Therefore, timely diagnosis and differentiation of colitis and colorectal cancer are crucial. This study introduces a novel activatable carboxylesterase 2 (CES2) fluorescent probe, DBF-CES2, consisting of a cationic indolium fluorophore and a CES2-specific benzyl ester recognition group. The probe operates via the intramolecular charge transfer (ICT) mechanism. Upon binding and hydrolysis by CES2, a potent electron-donating hydroxyl group is released, enhancing the ICT effect and increasing fluorescence intensity, emitting red fluorescence light (λem = 680nm). The probe had a large Stokes shift of 167nm and a detection limit as low as 0.70ng/mL. It also had high selectivity, sensitivity, and biocompatibility. Cellular imaging experiments demonstrated that CES2 expression levels in colorectal cancer cells were higher than those in normal cells. The DBF-CES2 probe specifically recognized endogenous CES2 in colorectal cancer cells, promptly distinguishing them from normal cells. In vivo imaging in mice confirmed that the probe could differentiate between colitis and colorectal cancer, allowing for the assessment of the therapeutic effects of two drugs. The synthesized CES2-targeting organic small molecule fluorescent probe DBF-CES2 is a new molecular tool for the early diagnosis of colitis and colorectal cancer-related diseases, holding significant potential in clinical diagnostics.

Cooperation of ICT and intramolecular spirocyclization: Construction of versatile fluorescent probe visualizing triple organelles in three distinct channels

The cooperation and interplay among multiple organelles play essential roles in a variety of crucial biological and pathological procedures. Fluorescent probes enabling discriminative visualization of triple organelles with different emission colors were promising molecular tools to investigate organelles interaction network, which however were rarely reported. Herein, by cooperating the polarity-sensitive intramolecular charge transfer (ICT) mechanism and pH-responsible intramolecular reversible cyclization reaction, we have constructed a fluorescent probe to distinguish lipid droplets (LDs), mitochondria, and lysosomes in three distinct channels without crosstalk emission. The probe (Triorg) presented in ring-open form in lysosomes to emit red fluorescence, while kept in ring-close form in LDs and mitochondria but distinguish the two organelles based on their different polarity. As a result, Triorg discriminated LDs, mitochondria, and lysosomes with blue, green, and red emission channels, respectively. Particularly, Triorg enabled visualizing LDs accumulation and consumption with blue emission, and detecting mitochondrial dysfunction and lysosomal damages with decreased green and red emission, respectively. The lysosomal damage and LDs consumption induced by chlorpromazine (a drug) and phenylarsine oxide (a toxic substance) have been revealed. The amount, morphologies, and three-dimension distribution of the three organelles in live tissues were also successfully visualized with Triorg.

2D/2D Bi2MoO6/g-C3N4 direct Z-scheme Van der Waals heterojunction photocatalyst for boosting nitrogen fixation

Although photocatalytic nitrogen fixation is an efficient and environmentally-friendly technology for ammonia synthesis, it still faces challenges such as high recombination of photo-generated carriers and a lack of active sites for the reaction of catalysts. Constructing direct Z-scheme heterojunctions is considered an effective strategy to enhance carrier separation efficiency of catalysts. However, it still encounters the challenge of lacking surface active reaction sites. The 2D Z-scheme Van der Waals heterojunction has the same charge transfer mechanism of direct Z-scheme heterojunctions, ensuring high carrier efficiency and retaining strong redox ability. Additionally, its layered structure provides a large number of reactive sites. In this study, theoretical calculation simulation was employed to predict the properties of Bi2MoO6 (BMO) and g-C3N4 (CN), and to simulate the dynamic behavior of photogenerated carriers. A 2D/2D CN-BMO direct Z-scheme Van der Waals heterojunction was constructed. Remarkably, this heterojunction demonstrated significantly enhanced photocatalytic ammonium generation capabilities. This study provides valuable insights for the development of advanced heterojunction photocatalysts.

Designing interfacial chemical bond by anchoring defective CeO2-x nanorods with bismuth-rich Bi4O5Br2 nanosheets: Modulated Z-scheme charge transfer for photocatalytic degradation of antibiotic

Exploring and implementing precise carrier-transfer channels in the interface of Z-scheme heterojunctions are crucial and considered significant challenges. Here, a one-dimensional/two-dimensional (1D/2D) heterostructure Z-scheme photocatalyst was constructed by in situ growing of defective CeO2-x nanorods on the surface of Bi-rich Bi4O5Br2 nanosheets, which was coordinated by the interface bonding and the dual oxygen vacancies for efficient photocatalytic degradation activity of tetracycline. Both experimental results and theoretical calculations elucidated that the compact 1D/2D structure and dual oxygen vacancies induced interfacial Br-O-Ce bond to act as charge bridges providing direct ohmic contacts, thus realizing a Z-scheme charge transfer mechanism that promoted effective charge separation and maximized the redox capacity. Meanwhile, the surface potential was 31.92 mV, indicating the creation of a strong interface electric field (IEF). As part of the strong synergy of the Br-O-Ce bond, IEF and dual oxygen vacancies, the optimal defective CeO2-x@Bi-rich Bi4O5Br2 exhibited superior photocatalytic activity and 85.40 % tetracycline (TC) was decomposed within 40 min, which was 65.7 and 2.1 times higher than CeO2-x and Bi4O5Br2, respectively. Besides, electrons quickly migrated through the formed Br-O-Ce bonds to the catalytic sites, accelerating charge separation. Our findings provide new insights to develop the interfacial chemical bond and dual oxygen vacancies modulated Z‐scheme charge transfer for efficient photocatalysis.

A coumarin-naphthalimide-based fluorescent probe for the ratiometric detection of Hg2+ utilizing an ICT-FRET mechanism

Mercury, as one of the most toxic elements in environmental and biological samples, can poses a grave threat to the integrity of the nervous, reproductive, immune, and digestive systems. Hence, it is significant to exploit convenient and rapid fluorescent probes featuring high sensitivity and selectivity for monitoring the concentration level of mercury ions (Hg2+). In this paper, a ratiometric fluorescent probe for Hg2+ based on intramolecular charge transfer (ICT) and fluorescence resonance energy transfer (FRET) mechanisms was developed by using coumarin ad energy donor and naphthalimide as energy acceptor, and thionocarbonate as the recognizing group for Hg2+. When the probe alone was present in the system, the thionocarbonate group of the probe prevented the electron transfer and the ICT process was off, thus preventing the FRET process of the probe as well. The probe alone emitted the intrinsic blue fluorescence of coumarin upon excitation at 397 nm. After providing Hg2 the thionocarbonate unit reacted with Hg2+, which restored the ICT process of the naphthalimide donor, and the FRET process in turn took place. Upon adding Hg2+, the probe emitted yellow fluorescence. In addition, the fluorescence intensity ratio at 548 nm and 476 nm (I548 nm/I476 nm) of the probe linearly corrected with the concentration of Hg²⁺ ions in the range of 0.1–12 μM. A limit of detection of 0.055 μM was obtained. Meanwhile, the probe exceptional recognized Hg2+ across a broad pH range (pH=4.00–10.00), including physiological pH. Cellular studies further confirmed the probe's negligible cytotoxicity and its potential for ratiometric fluorescence imaging of intracellular Hg²⁺ ions in A549 cells. In addition, the probe was loaded on filter paper to make test strips and combined with a smartphone to achieve rapid visual quantitative detection of Hg2+.

Quantum chemical study of new oxadiazoles as efficient optical and nonlinear optical and photovoltaic materials under gas, PCM and COSMO solvent effects

The science of organic optical and nonlinear optical (NLO) materials has been captivating the scientific community owing to their extensive applications in optoelectronics, OLEDs, and telecommunications. This study presents the design and investigation of novel organic compounds of pyrene and 1,3,4-oxadiazole derivatives (1-oxza to 6-oxza), featuring various push–pull combinations. Quantum chemical calculations were employed to determine linear polarizabilities (α) and third-order NLO polarizabilities (γ). Notably, the largest average third-order NLO polarizability value was found to be 254.9 × 10−36 esu for the finely tuned push–pull system 6-oxza, which is ∼35 times greater than that of the prototype NLO molecule of p-nitroaniline (p-NA). Among the derivatives, 1-oxza exhibits the highest linear isotropic polarizability (αiso) value of 61.59 × 10−24 esu, while 5-oxza displays the highest linear anisotropic polarizability (αaniso) value of 60.09 × 10−24 esu. A notable increase of approximately ∼1 to ∼2 times in < γ > is observed for selected compounds (1-oxza, 4-oxza, 6-oxza), indicating that the Conductor-like Screening Model (COSMO) overestimates the values compared to the polarizable continuum model (PCM) and gas phases. Solvent significantly enhances third-order NLO polarizability amplitudes depending upon solvent polarity and strength of substitution groups. We calculated the frequency-dependent third-order NLO polarizability of 6-oxza at laser wavelengths ranging from 1400 to 1970 nm. The second hyperpolarizability EFISHG process (γ(−2ω; ω, ω, 0)) was calculated at a laser wavelength of 1400 nm, and the γ-amplitude was found to be 400.1 × 10−36 esu. The remarkable hyperpolarizability response in the gas phase is corroborated by TD-DFT calculations, which reveal a larger transition dipole moment of 3.062 and a lower transition energy of 3.780 eV as origin of larger hyperpolarizability for 6-oxza. A comprehensive analysis was performed based on FMOs for designed compounds to elucidate the intramolecular charge transfer (ICT) mechanisms and observed a notable reduction in energy band gap 4.89 eV for 6-oxza, which is responsible for enhanced NLO response. Additionally, DOS maps revealed the quantitative contributions of HOMOs and LUMOs for crucial electronic states related to the efficient ICT process. Additionally, we analyzed the photovoltaic properties and found that 6-oxza has the highest dye regeneration and the lowest open-circuit voltages of 1.89 eV and 2.22 eV, respectively. Our designed model compounds can put real-time such compounds under spotlight of scientific interests which seeks more efficient optical and NLO properties.

Activation of PAA at the Fe-Nx Sites by Boron Nitride Quantum Dots Enhanced Charge Transfer Generates High-Valent Metal-Oxo Species for Antibiotics Degradation.

Advanced oxidation processes (AOPs) based on peracetic acid (PAA) offer a promising strategy to address antibiotic wastewater pollution. In this study, Fe-doped graphitic carbon nitride (g-C3N4) nanomaterials were used to construct Fe-Nx sites, and the electronic structure was tuned by boron nitride quantum dots (BNQDs), thereby optimizing PAA activation for the degradation of antibiotics. The BNQDs-modified Fe-doped g-C3N4 catalyst (BNQDs-FCN) achieved an excellent reaction rate constant of 0.0843 min-1, marking a 21.6-fold improvement over the carbon nitride (CN)-based PAA system. DFT calculations further corroborate the superior adsorption capacity of the Fe-Nx sites for PAA, facilitating its activation. Charge transfer mechanisms, with PAA serving as an electron acceptor, were identified as the source of high-valent iron-oxo species. Moreover, the BNQDs-FCN system preferentially targets oxygen-containing functional groups in antibiotic structures, elucidating the selective attack patterns of these highly electrophilic species. This research not only elucidates the pivotal role of high-valent iron-oxo species in pollutant degradation within the PAA-AOPs framework but also pioneers a wastewater treatment system characterized by excellent degradation efficiency coupled with low ecological risk, thereby laying the groundwork for applications in wastewater management and beyond.

Electrocatalytic mechanism for overall water splitting to produce sustainable hydrogen by 2D Janus MoSH monolayer

In the present work, we investigates the potential of two dimensional (2D) Janus MoSH monolayer as an electrocatalyst for overall water splitting using first-principles calculations. Our results shows that 2D Janus MoSH monolayer exhibits excellent structural stability and electronic properties, which are essential for efficient electrocatalysis. We find that the charge transfer mechanism between Mo and S atoms plays a crucial role in the electrocatalytic activity of 2D Janus MoSH monolayer. Due to the asymmetric structure of MoSH monolayer, it has intrinsic electric field with dipole moment of 0.24 D. Moreover, we demonstrate that 2D Janus MoSH monolayer exhibits high catalytic activity for both hydrogen evolution reaction (HER) with overpotential 0.04 V and oxygen evolution reaction (OER) with overpotential 0.11 V, making it a promising candidate for overall water splitting. Our findings have significant implications for the design and optimization of 2D monolayered materials for renewable energy production. By providing insights into the underlying mechanisms of HER and OER on 2D Janus MoSH monolayer, our study paves the way for the development of efficient and sustainable electrocatalysts for water splitting. We hope that current work will be helpful in understanding the electrocatalytic mechanism of 2D Janus MoSH monolayer and its potential applications in renewable energy production.

Synthesis of Closely-Contacted Cu2O-CoWO4 Nanosheet Composites for Cuproptosis Therapy to Tumors With Sonodynamic and Photothermal Assistance.

Cuproptosis offers a promising and selective therapeutic strategy for cancer therapy. To fully realize its potential, the development of novel cuproptosis therapeutic agents and the achievement of efficient copper release are critical steps forward. Herein, closely-contacted Cu2O-CoWO4 nanosheet heterojunctions (CCW-NH) are successfully synthesized using an in-situ process for cuproptosis therapy. The efficient release of copper ions from CCW-NH can be triggered by ultrasound irradiation, primarily due to the generation of superoxide radicals as the sonodynamic agents via the Z-scheme charge transfer mechanism. When subjected to the combined effects of ultrasound and laser irradiation, the effective release of copper ions is increased by 1.7 times compared to the untreated group, significantly enhancing the efficiency of cuproptosis. And the incorporation of CCW-NH and L-arginine into the temperature-sensitive injectable hydrogel (HP-CCW@LA) ultimately achieved a tumor inhibition rate of up to 95.1%. L-arginine, serving as a reducing agent, enabled the sustained release of highly active Cu+ during treatment. Notably, after treating tumors with HP-CCW@LA, the tumor microenvironment is leveraged to promote copper ion conversion, which offers the potential for monitoring tumor therapy efficacy through magnetic resonance imaging. This work offers a novel integrated strategy for the development of new cuproptosis agents and therapeutic evaluation.

Boosted photoinduced charge separation in FeNi2S4@Cd0.9Zn0.1S Step-scheme heterojunction for photothermal assisted photocatalytic water splitting into hydrogen

Rational design of photocatalysts with photothermal effect to maximize light utilization is pivotal in achieving superior photocatalytic efficiency. In this work, by coating Cd0.9Zn0.1S (CZS) nanorods on hollow FeNi2S4 (FNS) microspheres with photothermal effect, a novel FeNi2S4@Cd0.9Zn0.1S (FNS@CZS) Step-scheme (S-scheme) heterojunction photocatalyst was constructed for efficient photothermal-assisted hydrogen (H2) evolution via simultaneously employing light and thermal energy. The hollow structure of FNS microsphere not only provides abundant reactive sites but also serves as a supportive substrate for CZS nanorods, effectively inhibiting their agglomeration. And the unique hollow structure of FNS allows for multiple reflections and refractions of visible light, enhancing the local temperature of the photocatalyst. This effectively minimizes thermal losses within the composite system, thereby enhancing the efficiency of light energy utilization. Furthermore, the formation of the S-scheme heterojunction facilitates the efficient separation of photogenerated charge carriers and enhances the activity of redox reactions, thereby boosting the overall photocatalytic activity. Experimental results reveal that the H2 production rate of the FNS@CZS heterojunction reaches 12.9 mmol·g−1·h−1, which is 25.1 times higher than that of pristine CZS. By controlling the experimental temperature, the impact of the photothermal effect on the photocatalytic H2 production rate has been clarified. According to relevant evidence from infrared thermography and DFT calculations, comprehensive analyses and discussions were conducted on the photothermal effect and S-scheme charge transfer mechanisms. This study offers guidance on designing photothermal-enhanced photocatalysts to achieve satisfactory H2 production activity.

Exploring the Electronic Interactions of Adenine, Cytosine, and Guanine with Graphene: A DFT Study.

This study has provided new insights into the interaction between graphene and DNA nucleobases (adenine, cytosine, and guanine). It compares how each nucleobase interacts with graphene, examining their selectivity and binding energy. The research also explores how these interactions impact the electronic properties of graphene, showing potential applications in graphene-based biosensors and DNA sequencing technologies. Additionally, the findings suggest potential uses in DNA sensing and the functionalization of graphene for various biomedical applications. This study employs density functional theory (DFT) methods, utilizing the B3LYP functional with the 6-311G basis set, to explore the electronic interactions between DNA nucleobases (adenine, cytosine, and guanine) with pure graphene (Gr). We investigate various properties, including adsorption energy, HOMO-LUMO energy levels, charge transfer mechanisms, dipole moments, energy gaps, and density of states (DOS). Our findings indicate that cytosine interacts most favorably with graphene through its oxygen site (Gr-Cyt-O), exhibiting the strongest adsorption. Additionally, adenine's interaction significantly enhances its electronegativity and chemical potential, particularly at the nitrogen position, while decreasing its electrophilicity. Guanine, characterized by the smallest energy gap, demonstrates the highest conductivity among the nucleobases. These results suggest that graphene possesses advantageous properties as an adsorbent for guanine, highlighting its potential applications in biosensor technology.

Photocatalytic Enhancement and Recyclability in Visible-Light-Responsive 2D/2D g-C3N4/BiOI p-n Heterojunctions via a Z-Scheme Charge Transfer Mechanism.

With the intensification of the energy crisis and the growing concern over environmental pollution, particularly the discharge of organic dye pollutants in industrial wastewater, photocatalytic degradation of these contaminants using solar energy has emerged as an effective, eco-friendly solution. In this study, we successfully synthesized 2D/2D g-C3N4/BiOI p-n heterojunctions via a simple precipitation method and a high-temperature calcination method. The unique 2D structures of g-C3N4 nanosheets (NSs) and BiOI NSs, coupled with the synergistic effect between the two materials, significantly enhanced the photocatalytic degradation performance of the heterojunctions under simulated sunlight. The band structures, as determined by Tauc curves, Mott-Schottky curves and XPS-VB analysis, revealed a Z-scheme charge transfer mechanism that efficiently reduced charge carrier recombination and improved electron-hole separation. The photocatalytic activity of 2D/2D g-C3N4/BiOI p-n heterojunctions for rhodamine B (Rh B) degradation reached 99.7% efficiency within 60 min, a 2.37-fold and 1.27-fold improvement over pristine BiOI NSs and g-C3N4 NSs, respectively. Furthermore, the heterojunction exhibited excellent recyclability stability, with the degradation efficiency decreasing by only 1.2% after five cycles. Radical scavenging experiments confirmed the involvement of superoxide radicals (∙O2-) and hydroxyl radicals (∙OH) as the primary reactive species in the degradation process. This work highlights the potential of 2D/2D g-C3N4/BiOI p-n heterojunctions for efficient photocatalytic applications in environmental remediation.

Light-dependent electron transfer mechanism on a Z-scheme MIL-100(Fe)/AgCl/Ag heterostructure for photocatalytic degradation

Research on the changes in material properties caused by different light sources and the various photocatalytic mechanisms generated is of great significance for exploring new catalysts and improving catalytic efficiency. In this study, a novel composite of MIL-100(Fe)/AgCl/Ag was synthesized for photocatalytic degradation of organic pollutants. Techniques such as ultraviolet (UV)-visible spectroscopy and surface-enhanced Raman spectroscopy (SERS) were employed to monitor the degradation process of small molecule organic pollutants in real-time under different light sources. The research found that the catalytic efficiency of the catalyst under visible light is markedly higher than that under UV light. This phenomenon can attributed to the dynamic changes in the material’s properties, particularly the adjustment of the interface electric field under different light sources. Specifically, under UV light irradiation, the catalyst follows a Z-scheme electron transfer pathway to achieve interband transitions. In contrast, under visible light irradiation, it operates through a Z-scheme electron transfer mechanism related to surface plasmon resonance (SPR), which effectively promotes separation of electrons and holes. As a results, the apparent reaction rate is approximately 2.5 times higher compared to that under UV light conditions. This study contributes to a deeper understanding of charge transfer mechanisms in photocatalytic reactions under different wavelength light sources, and could provide valuable insights for designing new light-responsive catalysts to improve their efficiency.

Energy harvesting through the triboelectric nanogenerator (TENG) based on polyurethane/cellulose nanocrystal

This study investigates how physical and mechanical properties affect the performance of triboelectric nanogenerators (TENGs). Polyurethane (PU) was prepared using two methods: (i) one-step PU (non-chain extended polyurethane) and (ii) two-step PU (chain extended polyurethane) via the prepolymer method; both types were filled with different concentrations of nanocrystalline cellulose. Mechanical properties significantly influence the deformation at the material interface that occurs during contact or friction. Key surface characteristics, including surface energy, geometry, and physicochemical properties, affect the effective contact area and potential distribution. One-step PU with 0.1 % CNC demonstrates a maximum capacitance of 29.20 pF, a voltage of 2.04 V, an electric current of 0.43 µA and power of 0.89 µW, representing a 74.5 % increase in power compared to the neat one-step PU, exhibits significant potential for TENG applications. Performance improvements are associated with lower concentrations of cellulose nanocrystals, enhanced hydrogen bonding, and beneficial surface energy. The observed enhancements in output are attributed to improved internal polarization from well-dispersed crystalline nanocellulose, increased crystallinity of the soft segment, and reduced charge transfer mechanisms due to amino groups in the chain extender. However, the impact of the molecular structure and conformation of polyurethanes on triboelectrification remains unclear, highlighting the need for theoretical models and experimental data. This research provides a practical approach for developing stretchable triboelectric materials with enhanced mechanical properties, emphasizing the importance of considering factors such as mechanical parameters, nanofiller content, and surface physicochemical properties to optimize TENG design.

Multifunctional Triboelectric Metamaterials with Unidirectional Charge Transfer Channels for Linear Mechanical Motion Energy Harvesting

AbstractConventional triboelectric generators (TEGs) have been developed to mainly harvest the energy of linear mechanical motions and convert it usually into oscillating or pulsive, but not sustainable, electrical outputs. In this study, unidirectional charge transfer mechanisms are introduced to develop a triboelectric mechanical metamaterial (TMM) with sustainable electrical outputs. Density functional theory and experimental analyses demonstrate three minimum necessary components of TMMs fabricated by only two triboelectric materials (i.e., copper and PTFE) to generate sustainable electrical outputs. Under a wide range of compression‐tension strain of ±50%, the maximum open‐circuit voltage, short‐circuit current, and volumetric power density are 3860 V, 8 µA, and 365.3 kW m−3, respectively. Different from most conventional cellular solids, the mechanical energy dissipation of the TMMs increases quadratically with the unit cell number. High volumetric electromechanical efficiency is achieved when the unit cell is miniaturized. In addition to energy harvesting and mechanical energy dissipation, TMMs can sense the displacement by counting the number of distinctive peaks in the short‐circuit charge transfer or reaction force versus time curves. The extreme electromechanical functionalities of the TMMs facilitate their applications in intelligent suspension systems, miniaturized green power sources, and self‐sensing energy harvesters.

Synergistic effects of Cu7S4@Cu2O core-shell photocatalyst and S-scheme heterojunction in photocatalytic CO2 reduction

In this study, a Cu7S4@Cu2O core-shell S-scheme heterojunction photocatalyst was synthesized via in-situ sulfurization of Cu2O, aimed at enhancing the photocatalytic reduction of CO2 to CO under UV–visible light. Both experimental investigations and Density Functional Theory (DFT) calculations confirmed the S-scheme charge transfer mechanism between the Cu7S4 shell and Cu2O core. The tightly bonded Cu7S4 shell effectively facilitates the separation of photogenerated charge carriers by promoting electron migration from the Cu2O core to the Cu7S4 shell, while significantly improving the photocorrosion resistance of Cu2O. As a result, the Cu7S4@Cu2O catalyst demonstrated superior cycling stability with a CO production rate of 6.19 μmol∙g−1∙h−1. The CO2 photocatalytic reduction mechanism was further elucidated using in-situ infrared spectroscopy, offering critical insights into charge transfer processes. This work provides an approach to the design of highly efficient and stable core-shell S-scheme heterojunction photocatalysts for CO2 reduction.

Breaking Activity‐Durability Inverse Relationship via Electrode Engineering by Utilizing β‐MnO2/RuO2 Heterostructures for Efficient Seawater Electrolysis

AbstractSignificant efforts are underway to enhance the efficiency of water electrolysis for sustainable hydrogen production. Approaches that were explored are the design of an efficient anode, engineering of electrolytes, and application of diffusion protective layer over the catalyst to protect it from corrosive reactions. Here we are exploring the engineering of electrode fabrication to enhance the efficacy of anode catalysts by ensuring that the materials are carefully selected. β‐MnO2 has been used to develop a cost‐effective method for electrode fabrication that establish a Schottky junction at heterostructure interface. This method transforms commercial RuO2, which is considered to be less active and stable, highly selective for chlorine oxidative reactions, into a highly active, stable, and OER‐selective in alkaline medium and surrogate seawater. With the help of thorough electrochemical techniques, we found that this engineering significantly improves the effective electrochemical surface area, and higher kinetics and conversion per unit site, profoundly affecting the charge transfer mechanism and optimizing the adsorption of OER intermediates, resulting in much‐increased mass activity. It is observed that the selectivity of the OER was enhanced due to the Lewis acid repercussions of β‐MnO2.

Impact of NaCF3SO3 on charge transfer mechanism in gellan gum–based solid polymer electrolytes

Impact of NaCF3SO3 on charge transfer mechanism in gellan gum–based solid polymer electrolytes

How to Assess and Predict Electrical Double Layer Properties. Implications for Electrocatalysis.

The electrical double layer (EDL) plays a central role in electrochemical energy systems, impacting charge transfer mechanisms and reaction rates. The fundamental importance of the EDL in interfacial electrochemistry has motivated researchers to develop theoretical and experimental approaches to assess EDL properties. In this contribution, we review recent progress in evaluating EDL characteristics such as the double-layer capacitance, highlighting some discrepancies between theory and experiment and discussing strategies for their reconciliation. We further discuss the merits and challenges of various experimental techniques and theoretical approaches having important implications for aqueous electrocatalysis. A strong emphasis is placed on the substantial impact of the electrode composition and structure and the electrolyte chemistry on the double-layer properties. In addition, we review the effects of temperature and pressure and compare solid-liquid interfaces to solid-solid interfaces.