Charge Transfer Kinetics Research Articles

Interfacial Charge Transfer in Photoexcited QD-Molecule Composite of Tetrahedral CdSe Quantum Dot Coupled with Carbazole.

Photoexcited charge transfer dynamics in CdSe quantum dots (QDs) coupled with carbazole were explored to model QD-molecule systems for light-harvesting applications. The absorption spectra of QDs with different sizes, i.e., Cd35Se20X30L30 (T1), Cd56Se35X42L42 (T2), and Cd84Se56X56L56 (T3) were simulated with quantum dynamical methods, which qualitatively match the reported experimental spectra. The carbazole is attached with a 3-amino group at the apex position of T1 (namely T1-3A-Cz), establishing proper electronic communication between T1 and carbazole. The spectra of T1-3A-Cz is 0.22 eV red-shifted compared to T1. A time-dependent perturbation was applied in tune with the lowest energy peak (3.63 eV) of T1-3A-Cz to investigate the charge transfer dynamics, which revealed an ultrafast charge separation within the femtosecond time scale. The electronic structure showed a favorable energy alignment between T1 and carbazole in T1-3A-Cz. The LUMO of carbazole was situated below the conduction band of the QD, while the HOMO of carbazole mixed perfectly with the top of the valence band of the QD, developing the interfacial charge transfer states. These states promoted the photoexcited electron transfer directly from the CdSe core to carbazole. A rapid and enhanced charge separation occurred with the laser field strength increasing from 0.001 to 0.005 V/Å. However, T1 connected to the other positions of carbazole did not show charge separation effectively. The photoinduced charge transfer is negligible in the case of T2-carbazole systems due to poor electronic coupling, and it is not observed in T3-carbazole systems. So, the T1-3A-Cz model acts as a perfect donor-acceptor QD-molecule nanocomposite that can harvest photon energy efficiently. Further enhancement of charge transfer can be achieved by coupling more carbazoles to the T1 QD (e.g., T1-3A-Cz2) due to the extension of hole delocalization between T1 and the carbazoles.

Promoting electrochemical rates by concurrent ionic-electronic conductivity enhancement in high mass loading cathode electrode

Enhancing the fast charging capacity of thick electrodes with high mass loading is imperative in expediting the widespread adoption of electric vehicles. Nonetheless, the insufficient charge transfer kinetics of thick electrodes hinder the movement of effective electrons and ions, hence diminishing capacity at high current rates. Herein, we applied sustainable and biodegradable cellulose nanocrystals (CNCs) as electrode additives. It is the first time to simultaneously improve the electronic conductivity by optimizing the carbon dispersion and establishing electron transfer networks, as well as boosting the ionic conductivity of electrodes by shortening the ion transfer pathway. Specifically, the LiNi0.6Mn0.2Co0.2O2 electrodes incorporating 1% dual functional CNCs additive exhibit improved effective electrical conductivity from 0.11 to 0.16 S/m and risen effective ionic conductivity from 0.36 to 0.62 S/m, in comparison to counterpart electrodes without CNCs. Therefore, the 1% CNC electrode with a high mass loading of 27.0 mg/cm2 delivers a discharge capacity of 128 mAh/g at 1 C, which is superior to that of the CNC-free electrodes (95 mAh/g). In short, this study presents a novel environmentally friendly, economically viable, and dual-functional electrode additive that enhances both electronic and ionic conductivities with the aim of facilitating the widespread adoption of fast-charging high mass loading electrodes.

Molybdenum diselenide/polymeric carbon nitride dual-homojunction photocatalyst with multi-step charge transfer for efficient catalytic carbon dioxide reduction

Due to the high dissociation energy of carbon dioxide (CO2) and sluggish charge transfer dynamics, photocatalytic CO2 reduction with high performance remains a huge challenge. Herein, we report a novel dual-homojunction photocatalyst comprising of cyano/cyanamide groups co-modified carbon nitride (CN-TH) intramolecular homojunction and 1 T/2H-MoSe2 homojunction (denoted as 1 T/2H-MoSe2/CN-TH) for enhanced photocatalytic CO2 reduction. In this dual-homojunction photocatalyst, the intramolecular CN-TH homojunction could promote the intralayer charge separation and transfer owing to the strong electron-withdrawing capabilities of the two-type cyanamide, while the 1 T/2H-MoSe2 homojunction mainly contributes to a promote interlayer charge transport of CN-TH. This could consequently induce a tandem multi-step charge transfer and accelerate the charge transfer dynamics, resulting in enhanced CO2 reduction activities. Thanks to this tandem multi-step charge transfer, the optimized 1 T/2H-MoSe2/CN-TH dual-homojunction photocatalyst presented a high CO yield of 27.36 μmol·g−1·h−1, which is 3.58 and 2.87 times higher than those of 1 T/2H-MoSe2/CN and 2H-MoSe2/CN-TH single homojunctions, respectively. This work provides a novel strategy for efficient CO2 reduction via achieving a tandem multi-step charge transfer through designing dual-homojunction photocatalyst.

CdS-based Schottky junctions for efficient visible light photocatalytic hydrogen evolution

Heterojunctions photocatalysts play a crucial role in achieving high solar-hydrogen conversion efficiency. In this work, we mainly focus on the charge transfer dynamics and pathways for sulfides-based Schottky junctions in the photocatalytic water splitting process to clarify the mechanism of heterostructures photocatalysis. Sulfides-based Schottky junctions (CdS/CoP and CdS/1T-MoS2) were successfully constructed for photocatalytic water splitting. Because of the higher work function of CdS than that of CoP and 1T-MoS2, the direction of the built-in electric field is from CoP or 1T-MoS2 to semiconductor. Therefore, CoP and 1T-MoS2 can act as electrons acceptors to accelerate the transfer of photo-generated electron on the surface of CdS, thus improving the charge utilization efficiency. Meanwhile, CoP and 1T-MoS2 as active sites can also promote the water dissociation and lower the H+ reduction overpotential, thus contributing to the excellent photocatalytic hydrogen production activity (23.59 mmol·h−1·g−1 and 1195.8 mol·h−1·g−1 for CdS/CoP and CdS/1T-MoS2).

Interfacially Ordered NiCoMoS Nanosheets Arrays on Hierarchical Ti3C2Tx MXene for High‐energy‐density Fiber‐Shaped Supercapacitors with Accelerated Pseudocapacitive Kinetics

Balancing electrochemical activity and structural reversibility of fibrous electrodes with accelerated Faradaic charge transfer kinetics and pseudocapacitive storage are highly crucial for fiber‐shaped supercapacitors (FSCs). Herein, we report novel core‐shell hierarchical fibers for high‐performance FSCs, in which the ordered NiCoMoS nanosheets arrays are chemically anchored on Ti3C2Tx fiber. Beneficial from architecting stable polymetallic sulfide arrays and conductive networks, the NiCoMoS‐Ti3C2Tx fiber maintains fast charge transfer, low diffusion and OH‐ adsorption barrier, and stabilized multi‐electronic reaction kinetics of polymetallic sulfide. Consequently, the NiCoMoS‐Ti3C2Tx fiber exhibits a large volumetric capacitance (2472.3 F cm‐3) and reversible cycling performance (20,000 cycles). In addition, the solid‐state symmetric FSCs deliver a high energy density of 50.6 mWh cm‐3 and bending stability, which can significantly power electronic devices and offer sensitive detection for dopamine.

Charge Transfer Kinetics in Halide Perovskites: On the Constraints of Time-Resolved Spectroscopy Measurements.

Understanding photophysical processes in lead halide perovskites is an important aspect of optimizing the performance of optoelectronic devices. The determination of exact charge carrier extraction rate constants remains elusive, as there is a large and persistent discrepancy in the reported absolute values. In this review, we concentrate on experimental procedures adopted in the literature to obtain kinetic estimates of charge transfer processes and limitations imposed by the spectroscopy technique employed. Time-resolved techniques (e.g., transient absorption-reflection and time-resolved photoluminescence spectroscopy) are commonly employed to probe charge transfer at perovskite/transport layer interfaces. The variation in sample preparation and measurement conditions can produce a wide dispersion of the measured kinetic parameters. The selected time window and the kinetic fitting model employed introduce additional uncertainty. We discuss here evaluation strategies that rely on multiexponential fitting protocols (regular or stretched) and show how the dispersion in the reported values for carrier transfer rate constants can be resolved.

Synthesis of nanoflakes-covered microparticles of nickel-Application for electrocatalytic oxidation and quantitation of nitrofurazone

Nickel microparticles covered with nanoflakes (NMCN) were hydrothermally synthesized in an alkaline solution of acrylamide dissolved in ethylene glycol/ethylenediamine at 200 °C. Structure and morphology of NMCN were characterized by field-emission scanning electron microscopy and X-ray powder diffraction, respectively. NMCN was applied, as an electrode modifier, with a surface concentration of 5.1 × 10−8 mol cm−2, and a detailed study was performed for the kinetics of charge transfer across the modified electrode/electrolyte interface using cyclic voltammetry. For the redox transition of NMCN in an alkaline solution, electron transfer coefficient and apparent charge-transfer rate constant were acquired as 0.65 and 0.6 s−1, respectively. The modified electrode was then applied for a study on the electrocatalytic oxidation of nitrofurazone (NF) on the NMCN surface through an electrochemical-catalytic (EC') mechanism. The oxidation process was followed by a NF diffusion coefficient of 2.9 × 10−6 cm2 s−1 and a catalytic rate constant of 3.0 × 104 cm3 mol−1 s−1. Also, an electron transfer coefficient of 0.40 was attained. The modified electrode was employed as a novel, time-saving, sensitive and simple amperometric sensor for NF, and quantified the drug with a linear range of 30–570 μmol L−1 and a sensitivity of 0.694 ± 0.002 A L mol−1 cm−2. Also, a detection limit of 4.3 μmol L−1 was attained. The sensor was employed for direct assay of NF in the human serum and ointments.

37‐3: Donor‐Acceptor Alignment and Charge Separation in Small Molecule Organic Semiconductors

Understanding complex molecular interactions in OLED materials such as donor‐acceptor charge transfer are crucial for device efficiency. Utilizing simulation tools as a virtual microscope, we investigate how fundamental molecular properties, especially Coulomb interactions, impact charge transfer dynamics and overall device performance. Our findings reveal that molecular packing and microelectrostatic environments significantly influence charge transfer binding energy, underscoring the importance of molecular arrangement in material design. These insights, difficult to obtain experimentally, are pivotal in formulating design guidelines for high‐performance organic compounds, thereby advancing our understanding of OLED molecular interactions and aiding in the development of more efficient and durable devices.

Facile fabrication of SnO2/MnTe nanocomposite as an efficient electrocatalyst for OER in basic media

There is a strong demand for developing an extremely effective and robust electrocatalyst to facilitate oxygen evolution reaction in water electrolysis applications. Herein, we successfully produced SnO2/MnTe using an efficient ultrasonication technique that is cost-effective and readily accessible along with improved catalytic behavior. The physical properties of fabricated catalysts are examined to analyze textural, structural and morphological characteristics. The SnO2/MnTe nanocomposite exhibited the low overpotential (181 mV) at 10 mA cm−2 and smaller Tafel slope of 33 mV dec−1 in alkaline (1.0 M KOH) medium. Moreover, the material also showed prolonged and excellent stability over 50 h following 5000 stability cycles. Electrochemical impedance spectroscopy studies demonstrated that charge transfer kinetics at the catalyst-electrolyte interface could be achievable, with lower Rct values (0.8Ω) directing it to increase electrochemical behavior. The acquired outcomes obtained from electrochemical activity demonstrate the potential of SnO2/MnTe as a highly promising electrocatalyst for future electrochemical energy generation.

Impact of nuclear effects on the ultrafast dynamics of an organic/inorganic mixed-dimensional interface

Electron dynamics at weakly bound interfaces of organic/inorganic materials are easily influenced by large-amplitude nuclear motion. In this work, we investigate the effects of different approximations to the equilibrium nuclear distributions on the ultrafast charge-carrier dynamics of a laser-excited hybrid organic/inorganic interface. By considering a prototypical system consisting of pyrene physisorbed on a MoSe2 monolayer, we analyze linear absorption spectra, electronic density currents, and charge-transfer dynamics induced by a femtosecond pulse in resonance with the frontier-orbital transition in the molecule. The calculations are based on ab initio molecular dynamics with classical and quantum thermostats, followed by time-dependent density-functional theory coupled to multi-trajectory Ehrenfest dynamics. We impinge the system with a femtosecond (fs) pulse of a few hundred GW cm−2 intensity and propagate it for 100 fs. We find that the optical spectrum is insensitive to different nuclear distributions in the energy range dominated by the excitations localized on the monolayer. The pyrene resonance, in contrast, shows a small blue shift at finite temperatures, hinting at an electron-phonon-induced vibrational-level renormalization. The electronic current density following the excitation is affected by classical and quantum nuclear sampling through suppression of beating patterns and faster decay times. Interestingly, finite temperature leads to a longer stability of the ultrafast charge transfer after excitation. Overall, the results show that the ultrafast charge-carrier dynamics are dominated by electronic rather than by nuclear effects at the field strengths and time scales considered in this work.

Electrochemical Detection of Glyphosate in Surface Water Samples Based on Modified Screen-Printed Electrodes.

This study addresses the necessity to monitor the presence of glyphosate (Gly) in waters, highlighting the need for on-site detection of Gly by using electrochemical sensors in environmental and agricultural monitoring programs. Two approaches were employed: (1) modification with graphene decorated with gold nanoparticles (AuNPs-Gr) and dispersed in either dimethylformamide (DMF) or a solution containing Nafion and isopropanol (NAF), and (2) molecularly imprinted polymers (MIPs) based on polypyrrole (PPy) deposited on gold SPEs (AuSPE). Electrochemical characterization revealed that sensors made of AuNPs-Gr/SPCE exhibited enhanced conductivity, larger active area, and improved charge transfer kinetics compared to unmodified SPEs and SPEs modified with graphene alone. However, the indirect detection mechanism of Gly via complex formation with metallic cations in AuNPs-Gr-based sensors introduces complexities and compromises sensitivity and selectivity. In contrast, MIPPy/AuSPE sensors demonstrated superior performance, offering enhanced reliability and sensitivity for Gly analysis. The MIPPy/AuSPE sensor allowed the detection of Gly concentrations as low as 5 ng/L, with excellent selectivity and reproducibility. Moreover, testing in real surface water samples from the Olt River in Romania showed recovery rates ranging from 90% to 99%, highlighting the effectiveness of the detection method. Future perspectives include expanding the investigation to monitor Gly decomposition in aquatic environments over time, providing insights into the decomposition's long-term effects on water quality and ecosystem health, and modifying regulatory measures and agricultural practices for mitigating its impact. This research contributes to the development of robust and reliable electrochemical sensors for on-site monitoring of Glyphosate in environmental and agricultural settings.

Magnetic N-doped carbon derived from mixed ligands MOF as effective electrochemiluminescence coreactor for performance enhancement of SARS-CoV-2 immunosensor

COVID-19 as an infectious disease with rapid transmission speed is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), so, early and accurate diagnostics of COVID-19 is quite challenging. In this work, the selective and sensitive self-enhanced ECL method to detect of SARS-CoV-2 protein was designed with magnetic N-doped carbon derived from dual-ligand metal-organic frameworks (MOF) (CoO@N–C) with the primary and tertiary amino groups as a novel coreactant that covalently combined with Ru(bpy)2(phen-NH2)2+ as electrochemiluminescence (ECL) emitter. Mixed-ligand strategy and selected nitrogen-containing ligands, 4,4′,4′′-((1,3,5-triazine-2,4,6-triyl) tris-(azanediyl)) tribenzoic acid (H3TATAB) with 2-aminoterephthalic acid (BDC-NH2) were used for synthesis of the proposed MOF. Also, magnetic CoO@N–C with high synergistically charge transfer kinetics and good stability can be used as an effective platform/coreactor on the ITO electrode which load more Ru-complex as signal producing compound and SARS-CoV-2 N protein antibody to increase the sensitivity of the immunosensor. Furthermore, (CoO@N–C) as coreactor improved the ECL signal of the Ru (II)-complex more than 2.1 folds compared to tripropylamine. In view of these competences, the novel “on-off” ECL biosensor performed with great stability and repeatability for detection of SARS-CoV-2 protein, which exhibited a broad linearity from 8 fg. mL−1 to 4 ng. mL−1 (6 order of magnitude) and an ultra-low limit of detection 1.6 fg. mL−1. Finally, this proposed method was successfully applied to detect of SARS-CoV-2 N protein in serum sample with satisfactory results, indicating the proposed immunosensor has the potential for quick analysis of SARS-CoV-2.

MoS2-C superlattice cathodes for conductive additive-free sulfide electrolyte-based all-solid-state lithium batteries

Sulfide electrolytes play a crucial role in the pursuit of high-performance all-solid-state lithium batteries (ASSLBs). However, most sulfide electrolytes have intrinsic narrow electrochemical stability windows, and decomposition reactions are thermodynamically favorable, especially contact with conductive additive. These ongoing side reactions accelerate sulfide electrolytes degradation, posing a significant threat to the cycling stability of ASSLBs. Herein, we propose an effective approach to address this challenge by designing a MoS2-C superlattice structure. This architecture, characterized by a layer-by-layer inter-stacking of MoS2 nanosheets and carbon layers, endows it with excellent electronic conductivity and enhanced lithium diffusion kinetics. Leveraging this superlattice, ASSLBs incorporating MoS2-C superlattice as the cathode without conductive additive exhibit a substantial improvement in electrochemical performance, ultimately achieving a conductive additive-free ASSLB. Remarkably, the conductive additive-free ASSLBs based on the MoS2-C superlattice demonstrates outstanding stability, enduring 300 cycles with a capacity retention of 96.8 % at a 1 C rate. This enhancement can be attributed to the improved charge transfer kinetics of MoS2-C superlattice and the effective suppression of side reactions between the sulfide electrolyte and conductive additive. Our study presents a promising design strategy to achieve high-rate performance and tackle long-term challenges in the application of sulfide electrolytes-based ASSLBs.

Modeling of MoS2/Si heterostructure to study charge transfer dynamics

Here, we synthesized a MoS2/Si heterojunction device using a scalable approach involving DC sputtering coupled with sulfurization. The observed current–voltage characteristics unequivocally indicate a rectifying behavior at MoS2/Si heterointerface. To quantitatively assess the carrier dynamics, a comprehensive analysis utilizing thermionic emission and Landauer transport formalism model was employed. The spatial variation in current across the MoS2/Si devices suggests a potential influence of MoS2’s in-plane series resistance. Furthermore, the electrical behavior of the device is found to be temperature-dependent, with higher temperatures resulting in enhanced conductivity attributed to an increase in thermally generated charge carriers. As temperature rises, the Landauer current model observes an increased ratio of density of states to carrier injection rate, along with other temperature-dependent terms. Meanwhile, the thermionic current model maintains a fixed effective value for its material-dependent term, the Richardson constant, irrespective of temperature changes. Therefore, a comparative analysis between thermionic emission and Landauer transport formalism reveals that the conventional thermionic emission model better aligns with experimentally observed leakage current in reverse bias, showcasing a minimal barrier height at the heterojunction. This comprehensive investigation provides valuable insights into the charge transfer mechanisms at the MoS2/Si interface, opening avenues for its potential innovative applications in electronic devices.

Charge transfer dynamics in graphene quantum dot-porphyrin derivative nanohybrids appraised via experimental and theoretical calculations

This article is designed to unveil the electronic and spectroscopic property changes of electron withdrawing/releasing group substituted porphyrins, in porphyrin-graphene quantum dot nanohybrids via experimental and computational calculations. Herein, amino, methyl, fluoro & nitro derivatives of meso substituted Tetraphenylporphyrin referred as TAPP, TMPP, TFPP & TNPP respectively, are synthesized from the corresponding benzaldehydes. Charge transfer dynamics of their nanohybrid systems with graphene quantum dots are investigated by electronic spectroscopy, steady state fluorescence and lifetime decay analysis. Negative Gibb's free energy change and dynamic quenching constants stipulate a photoinduced electron transfer with dynamic quenching mechanism within the nanohybrids under scrutiny. Further the computational calculations with the aid of optimized geometries, scatter plots and energy decomposition analysis reflect the same experimental observations. Both experimental and computational studies show that the electron withdrawing group substituted porphyrins have higher interaction with GQD than the electron releasing group substituted porphyrins.

Long-life potassium metal batteries enabled by anion-derived solid electrolyte interphase using concentrated ionic liquid electrolytes

Potassium metal batteries (PMBs) show great potential as next-generation energy storage systems yet face challenges such as the dendritic growth of the potassium anode, leading to issues with cycle life and safety. This study reports a potassium salt-concentrated ionic liquid electrolyte (PCIL) consisting of potassium bis(fluorosulfonyl)imide (KFSI) and 1-methyl-1-propyl pyrrolidinium bis(fluorosulfonyl)imide (Pyr13FSI) to achieve long-life and, safe PMBs. PCIL presents several advantages including outstanding oxidation stability (≈5.2 V), decent ionic conductivity (4.0 mS cm−1 at 25 °C), and negligible flammability. Moreover, PCIL promotes the development of anion-derived solid-electrolyte interphase (SEI) with high inorganic content. This not only hinders the growth of potassium dendrites but also facilitates facile interfacial charge transfer kinetics. Benefiting from these advantages, PMBs (K||KVPO4F) employing PCIL exhibit remarkable cycle performances at both ambient and elevated temperatures (capacity retention after 300 cycles: 74.8% at 25 °C and 82.9% at 45 °C), surpassing the performance of conventional carbonate (1 M KPF6 EC/PC) and dilute potassium ionic liquid electrolyte (PIL). This work demonstrates the tangible capability of PCIL in realizing practical PMBs.

Enhanced optical and electrochemical properties of FeBTC MOF modified TiO2 photoanode for DSSCs application

In this work, iron based 1, 3, 5-tricarboxylic acid (FeBTC) was prepared via microwave-assisted method and incorporated into TiO2 via ultrasonic assisted method. The TiO2–FeBTC nanocomposites were characterized by XRD, FTIR, Raman, BET, FESEM, HRTEM, TGA, UV‒vis DRS and PL to understand their crystallographic, surface morphology, and optical characteristics. The Raman spectra showed a blue shift of Eg, A1g, and B1g peaks upon incorporation of FeBTC MOF onto TiO2. HRTEM and XRD analysis confirmed a mixture of TiO2 nanospheres and hexagonal FeBTC MOF morphologies with high crystallinity. The incorporation of FeBTC onto TiO2 improved the surface area as confirmed by BET results, which resulted in improved absorption in the visible region as a results of reduced bandgap energy from 3.2 to 2.84 eV. The PL results showed a reduced intensity for TiO2–FeBTC (6%) sample, indicating improved separation of electron hole pairs and reduced recombination rate. After fabrication of the TiO2–FeBTC MOF photoanode, the charge transfer kinetics were enhanced at TiO2–FeBTC MOF (6%) with Rp value of 966 Ω, as given by EIS studies. This led to high performance due to low charge resistance. Hence, high power conversion efficiency (PCE) value of 0.538% for TiO2–FeBTC (6%) was achieved, in comparison with other loadings. This was attributed to a relatively high surface area which allowed more charge shuttling and thus better electrical response. Conversely, upon increasing the FeBTC MOF loading to 8%, significant reduction in efficiency (0.478%) was obtained, which was attributed to sluggish charge transfer and fast electron–hole pair recombination rate. The TiO2–FeBTC (6%) may be a good candidate for use in DSSCs as a photoanode materials for improved efficiency.

Plasma-Engraved Lattice-Matched NiO/NiFe2O4 Heterostructure with Ample Oxygen Vacancies for Efficient Water Electrolysis and Zn-Air Batteries.

Heterogeneous interface and defect engineering offer effective pathways to accelerate oxygen evolution reaction (OER) charge transfer kinetics and motivate optimal intrinsic catalytic activity. Herein, we report the lattice-matched NiO/NiFe2O4 heterostructure with ample oxygen vacancies (Vo-NiO/NiFe2O4) induced by a feasible hydrothermal followed by calcination and plasma-engraving assistant technique, which shows the unique porous microflower arrangement of intertwined nanosheets. Benefitting from the synergetic effects between lattice-matched heterointerface and oxygen vacancies induce the strong electronic coupling, optimized OH-/O2 diffusion pathway and ample active sites, thus-prepared Vo-NiO/NiFe2O4 presents a favorable OER performance with a low overpotential (261 mV @ 10 mA cm-2) and small Tafel slope (39.4 mV dec-1), even surpassing commercial RuO2 catalyst. Additionally, the two-electrode configuration water electrolyzer and rechargeable zinc-air battery assembled by Vo-NiO/NiFe2O4 catalyst show the potential practical application directions. This work provides an innovative avenue for strengthening OER performance toward water electrolysis and Zn-air batteries via the interface and vacancy engineering strategy.

A multi-kernel-shell indium selenide@carbon nanosphere enabling high-performance lithium-ion batteries

Indium selenide has garnered significant attention for high volumetric capacities, but is currently plagued by the sluggish charge transfer kinetics, severe volume effect, and rapid capacity degradation that hinder their practical applications. Herein, we design, synthesize, and characterize a multi-kernel-shell structure comprised of indium selenide encapsulated within carbon nanospheres (referred to as m-K-S In2Se3@C) through an integrated approach involving a hydrothermal method followed by a gaseous selenization process. Importantly, experimental measurements and density functional theory calculations confirm that the m-K-S In2Se3@C not only improve the adsorption capability for Li-ions but also lower the energy barrier for Li-ions diffusion. Profiting from numerous contact points, shorter diffusion distances and an improved volume buffering effect, the m-K-S In2Se3@C achieves an 800 mA h g−1 capacity over 1000 loops at 1000 mA g−1, a 520 mA h g−1 capacity at 5000 mA g−1 and an energy density of 270 Wh kg−1 when coupled with LiFePO4, surpassing most related anodes reported before. Broadly, the m-K-S structure with unique nano-micro structure offers a new approach to the design of advanced anodes for LIBs.

Progress Made in Non-Metallic-Doped Materials for Electrocatalytic Reduction in Ammonia Production

The electrocatalytic production of ammonia has garnered considerable interest as a potentially sustainable technology for ammonia synthesis. Recently, non-metallic-doped materials have emerged as promising electrochemical catalysts for this purpose. This paper presents a comprehensive review of the latest research on non-metallic-doped materials for electrocatalytic ammonia production. Researchers have engineered a variety of materials, doped with non-metals such as nitrogen (N), boron (B), phosphorus (P), and sulfur (S), into different forms and structures to enhance their electrocatalytic activity and selectivity. A comparison among different non-metallic dopants reveals their distinct effects on the electrocatalytic performance for ammonia production. For instance, N-doping has shown enhanced activity owing to the introduction of nitrogen vacancies (NVs) and improved charge transfer kinetics. B-doping has demonstrated improved selectivity and stability, which is attributed to the formation of active sites and the suppression of competing reactions. P-doping has exhibited increased ammonia generation rates and Faradaic efficiencies, likely due to the modification of the electronic structure and surface properties. S-doping has shown potential for enhancing electrocatalytic performance, although further investigations are needed to elucidate the underlying mechanisms. These comparisons provide valuable insights for researchers to conduct in-depth studies focusing on specific non-metallic dopants, exploring their unique properties, and optimizing their performance for electrocatalytic ammonia production. However, we consider it a priority to provide insight into the recent progress made in non-metal-doped materials and their potential for enabling long-term and efficient electrochemical ammonia production. Additionally, this paper discusses the synthetic procedures used to produce non-metal-doped materials and highlights the advantages and disadvantages of each method. It also provides an in-depth analysis of the electrochemical performance of these materials, including their Faradaic efficiencies, ammonia yield rate, and selectivity. It examines the challenges and prospects of developing non-metallic-doped materials for electrocatalytic ammonia production and suggests future research directions.