Enhanced Charge Transfer Research Articles

Surface modification of LiFePO4 cathode enabled by highly Li+ mobility wrapping layer towards high energy and power density

Surface-modified cathode materials have been developed to achieve high-performance lithium secondary batteries with higher capacity, rate capability, and longer cycle performance than bulk active materials. In this study, a new surface-modified active material was explored through a low-temperature in situ-solution wrapping method (LiFePO4@Li4SiO4 composite). In addition, high Li-ion and electronic conductivity materials with amorphous nanostructures, in which the bulk LiFePO4 nanoparticles were covered with a Li4SiO4 layer, were demonstrated. In lithium-ion batteries, the LiFePO4@Li4SiO4 composite demonstrated enhanced charge transfer kinetics, which lowered the interfacial resistance between electrode and electrolyte and resulted in enhanced electrochemical performance when compared to that of bulk LiFePO4. Furthermore, Li4SiO4 is introduced as a surface stabilizer and effective Li-ion conductor to avoid side reactions and prevent the dissolution of active materials into the electrolyte. The designed cathode delivers a high specific discharge capacity of 171.8 mAh g-1 at 0.1 C with 99.76 % capacity retention after 150 cycles and a high capacity of 121.2 mAh g-1 at 10 C. Moreover, Li-ion full batteries employing LiFePO4@Li4SiO4 and graphite displayed a high specific energy density of 416.078 Wh kg-1 at a power density of 69.34 W kg-1 at 5 C. In summary, this paper reports a new strategy based on low-temperature in situ solution phase wrapping materials for developing active materials for high energy-power density energy storage devices.

Cobalt-Doped ZnO Nanocomposits for Efficient Dye Degradation: Charge Transfer.

Doping enhances the optical properties of high-band gap zinc oxide nanoparticles (ZnO NPs), essential for their photocatalytic activity. We used the combustion approach to synthesize cobalt-doped ZnO heterostructure (CDZO). By creating a mid-edge level, it was possible to tune the indirect band gap of the ZnO NPs from 3.1 eV to 1.8 eV. The red shift and reduction in the intensity of the photoluminescence (PL) spectra resulted from hindrances in electron-hole recombination and sp-d exchange interactions. These improved optical properties expanded the absorption of solar light and enhanced charge transfer. The field emission scanning electron microscopy (FESEM) image and elemental mapping analysis confirmed the CDZO's porous nature and the dopant's uniform distribution. The porosity, nanoscale size (25-55 nm), and crystallinity of the CDZO were further verified by high-resolution transmission electron microscopy (HRTEM) and selected area electron image analysis. The photocatalytic activity of the CDZO exhibited much greater efficiency (k=0.131 min-1) than that of ZnO NPs (k=0.017 min-1). Therefore, doped heterostructures show great promise for industrial-scale environmental remediation applications.

Withdrawal: Steering Sulfur Reduction Pathways via Cisplatin Enables High Performance in Lithium-Sulfur Batteries.

The sulfur reduction reaction (SRR) is an attractive 16-electron transfer process that endows Li-S batteries with a theoretical capacity of 1,672 mAh g-1. However, the slow kinetics and complex pathways of the SRR cause the shuttling of soluble polysulfides (PSs), thus fast capacity fading. Here, we report using cisplatin (cis-Pt) as a novel mediator to improve the SRR kinetics and a molecular probe to identify the SRR pathways. We show that cis-Pt with a reductive Pt2+ center can directly slice the S-S bonds of PSs, leading to enhanced charge transfer kinetics, guided SRR pathways, and depth conversion of PSs to Li2S. With cis-Pt added, Li-S coin cells deliver a maximum specific capacity of 1,437 mAh g-1 and a capacity decay of 0.017% per cycle after 1000 cycles, while a pouch cell with a practical electrolyte-sulfur ratio (2.5 μl mg-1) exhibits a high energy density of 318.8 Wh kg-1. Our mechanistic studies reveal that cis-Pt steers the cathodic SRR pathways by generating redox active cis-Pt/PSs complexes, enabling the replacement of the sluggish SRR with a faster redox cycling of Pt4+/Pt2+ pairs. These findings provide insights into the rational design of functional mediators for tackling the cathodic challenges inside Li-S batteries.

Geometric and Electronic Structure Modulation to Optimize the Charge Transfer of TiO2 for Ultrasensitive and Stable SERS Sensing.

Exploring the relationship between semiconductor structure and surface-enhanced Raman scattering (SERS) activity was essential for the development of ultrasensitive SERS substrates. Herein, we report an ytterbium atomic doping strategy to render TiO2 (Yb-TiO2) highly SERS sensitive superior to pure TiO2, with a detection limit as low as 1 × 10-9 M for 4-mercaptobenzoic acid. First-principles density functional theory calculations reveal that ytterbium doping leads to high electrostatic properties, allowing for significant charge transfer from molecules to semiconductors. Theoretical and experimental results indicate that Yb-TiO2 has a smaller band gap and higher density of states, which effectively enhance charge transfer between molecules and substrates, resulting in significant SERS activity. More importantly, Yb-TiO2 was particularly stable in air and acid solution and can be used for trace molecule detection in extreme environments. We demonstrate a promising approach to construct ultrasensitive SERS by optimizing the electronic structure induced by geometric structures.

Theoretical Study of Metal-Ligand Interactions in Lead Complexes with Radiopharmaceutical Interest.

The 203Pb and 212Pb lead radioisotopes are attracting growing interest as they can aid in the development of personalized, targeted radionuclide treatment for advanced and currently untreatable cancers. In the present study, the bonding interactions of Pb2+ with twelve macrocyclic ligands, having an octa and nona coordination, were assessed using Density Functional Theory (DFT) calculations. The molecular structures in an aqueous solution were computed utilizing the polarized continuum model. The preference for the twisted square antiprismatic (TSAP) structure was confirmed for ten out of the eleven cyclen-based complexes. The characteristics of the bonding were assessed using a Natural Energy Decomposition Analysis (NEDA). The analysis revealed a strong electrostatic character of the bonding in the complexes, with minor variations in electrical terms. The charge transfer (CT) had a comparable energetic contribution only in the case of neutral ligands, while in general, it showed notable variations regarding the various donor groups. Our data confirmed the general superiority of the carboxylate O and aromatic N donors. The combination of the selected efficient pendant arms pointed out the superiority of the acetate pendant arms and the lack of significant cooperation between the different pendant arms in the probed ligands. Altogether, the combination led only to a marginal enhancement in the total CTs in the complexes.

Utilizing diffusion tensor imaging as an image biomarker in exploring the therapeutic efficacy of forniceal deep brain stimulation in a mice model of Alzheimer’s disease

Objective.With prolonged life expectancy, the incidence of memory deficits, especially in Alzheimer's disease (AD), has increased. Although multiple treatments have been evaluated, no promising treatment has been found to date. Deep brain stimulation (DBS) of the fornix area was explored as a possible treatment because the fornix is intimately connected to memory-related areas that are vulnerable in AD; however, a proper imaging biomarker for assessing the therapeutic efficiency of forniceal DBS in AD has not been established.Approach.This study assessed the efficacy and safety of DBS by estimating the optimal intersection volume between the volume of tissue activated and the fornix. Utilizing a gold-electroplating process, the microelectrode's surface area on the neural probe was increased, enhancing charge transfer performance within potential water window limits. Bilateral fornix implantation was conducted in triple-transgenic AD mice (3 × Tg-AD) and wild-type mice (strain: B6129SF1/J), with forniceal DBS administered exclusively to 3 × Tg-AD mice in the DBS-on group. Behavioral tasks, diffusion tensor imaging (DTI), and immunohistochemistry (IHC) were performed in all mice to assess the therapeutic efficacy of forniceal DBS.Main results.The results illustrated that memory deficits and increased anxiety-like behavior in 3 × Tg-AD mice were rescued by forniceal DBS. Furthermore, forniceal DBS positively altered DTI indices, such as increasing fractional anisotropy (FA) and decreasing mean diffusivity (MD), together with reducing microglial cell and astrocyte counts, suggesting a potential causal relationship between revised FA/MD and reduced cell counts in the anterior cingulate cortex, hippocampus, fornix, amygdala, and entorhinal cortex of 3 × Tg-AD mice following forniceal DBS.Significance.The efficacy of forniceal DBS in AD can be indicated by alterations in DTI-based biomarkers reflecting the decreased activation of glial cells, suggesting reduced neural inflammation as evidenced by improvements in memory and anxiety-like behavior.

Heterogeneous Nucleation and Enhanced Charge Transfer via Amorphous Metal‐Organic Frameworks for Efficient and Stable Perovskite Solar Cells

AbstractThe two‐step sequential deposition method is considered a potential way for the large‐scale manufacture of perovskite solar cells (PSCs) with high power conversion efficiency and reproducibility. However, the dense lead iodide (PbI2) film interferes with its full contact with organic solutions, resulting in an inadequate reaction at the interface. Herein, 2 kinds of metal‐organic framework (MOF) are introduced, amorphous Ni‐MOF‐74 (amNi‐MOF‐74) and crystalline Zn‐MOF‐74 (crZn‐MOF‐74), into PbI2 for regulating crystallization. Compared to crZn‐MOF‐74, the incorporation of amNi‐MOF‐74 exhibited rapid nucleation, resulting in high‐quality perovskite films with large grain size, low trap density, and enhanced charge transfer between the perovskite and charge transfer layers. Meanwhile, the content of unstable phase PbI2 left in perovskite films due to insufficient reaction is also reduced. The amNi‐MOF‐74 modified PSCs exhibited a champion power conversion efficiency of 24.17% with good humidity and thermal stability. The unencapsulated device maintains 90% of its initial efficiency after 1000 h storage in dark ambient conditions with ≈30% relative humidity. This strategy provides an effective approach for promoting the crystallization process of perovskite and fabricating efficient and stable PSCs.

Investigation on the carrier dynamics and energy band of the CVD-grown large area WS2/Bi2O2Se heterostructure

Bismuth oxyselenide (Bi2O2Se) emerged as a prominent member of the quasi-2D layered material family, possesses appealing characteristics for optoelectronic applications including impressive environmental stability and high carrier mobility. Recently, although significant advancements have been made in the initial research on the optoelectronic characteristics of Bi2O2Se-based heterostructures, there remains a lack of comprehensive study on the carrier dynamics and energy band within these structures. In this work, large-area (1 cm × 1 cm) continuous Bi2O2Se and monolayer WS2 films were grown by chemical vapor deposition (CVD) method, and the related WS2/Bi2O2Se heterostructures were successfully constructed. Triple decay processes with lifetimes ofτ1 ∼ 298 ps, τ2∼37 ps andτ3 ∼ 1.58 ns are observed through time-resolved photoluminesce (TRPL), which were attributed to the recombination of neutral excitons, trions, and interlayer excitons, respectively. Then, the energy band structure was investigated through x-ray photoelectron spectroscopy, revealing a type-Ⅱ band alignment at the heterointerface. The valence band offset was 0.19 eV, while conduction band offset was approximately 1.09 eV as confirmed by ultraviolet photoelectron spectroscopy. As a result, the WS2/Bi2O2Se junction enhances charge transfer and interlayer interactions by the aid of interface build-in electric field. These results showcase the potential of integrating Bi2O2Se with other 2D semiconductors to form heterostructures possessing novel charge dynamic behaviors, and provide valuable understanding into the functionality of optoelectronic devices that rely on these 2D heterostructures.

Elevating electron transfer of recyclable SERS sensor using AuNPs/TiO2/Ti3C2 heterostructures for detection of malachite green in sunfish

Malachite green (MG)-contaminated aquatic products pose a serious threat to animal and human health. Hence, a novel recyclable surface-enhanced Raman scattering (SERS) substrate based on AuNPs/TiO2/Ti3C2 heterostructures was developed for the detection and degradation of MG in aquatic products. Specifically, AuNPs/TiO2/Ti3C2 heterostructures were synthesized by in situ oxidation and electrostatic adsorption based on Ti3C2 nanosheets. The excellent photocatalytic and SERS performance of the AuNPs/TiO2/Ti3C2 was demonstrated by Density functional theory (DFT) calculations and experimental results, which was attributed to the enhancement of charge transfer (CT) after the formation of heterostructures. The results demonstrate that AuNPs/TiO2/Ti3C2 is highly sensitive and recyclable. The detection limit of the sensor for MG is 8.91 × 10−5 mg/L. The sensor can be recycled for five times under the condition of light, and shows satisfactory self-cleaning performance in the food matrix, providing a possible alternative solution for the recyclable detection of MG.

Nanoscale Graded Nitrogen-Doping of TiO2 via Pulsed Laser Deposition for Enhancing Charge Transfer in Perovskite Solar Cells.

An electron transport layer (ETL) for highly efficient perovskite solar cells (PSCs) should exhibit superior electrical transport properties and have its band levels aligned with interfacing layers to ensure efficient extraction of photo-generated carriers. Nitrogen-doped TiO2 (TiO2:N) is considered a promising ETL because it offers higher electrical conductivity compared to conventional ETLs made from spray-pyrolyzed TiO2. However, the application of highly doped TiO2:N in PSCs is often limited by the misalignment of energy band levels with adjacent layers and reduced optical transparency. In this study, a novel approach is introduced to enhance the charge transport characteristics and accurately align the electronic band alignment of TiO2:N layer through nanoscale doping level grading, achieved through the pulsed laser deposition (PLD) technique. The TiO2:N ETL with a graded doping profile can combine characteristics of both highly doped and lightly doped phases on each side. Furthermore, a nanoscale doping gradation, employing an ultrathin sub-layer structure with graded doping levels, creates a smoothly cascading band-level alignment that bridges the adjacent layers, enhancing the transport of photo-generated carriers. Consequently, this method leads to a substantial increase in the power conversion efficiency (PCE), exceeding 22%, which represents a relative improvement of 11% compared to traditional spray-pyrolyzed TiO2-based PSCs.

Regioselective Doping into Atomically Aligned Core–Shell Structures for Electrocatalytic Reduction of Nitrate to Ammonia

AbstractThe electrochemical nitrate reduction reaction (NO3−RR) presents an environmentally friendly approach for efficient NO3− pollutant removal and ammonia (NH3) production, compared to the conventional Haber–Bosch approach. While core/shell engineering has demonstrated its potential in enhancing NO3−RR performance, significant synthetic challenges and limited shell layer modification capabilities impede the exploration of high‐performance NO3−RR core/shell catalysts. Herein, CuCoO/Co(OH)2 core/shell structure via in situ electrochemical activation is synthesized. The catalyst delivers a maximum NH3 Faradaic efficiency (FE) of 94.7% at −0.5 VRHE with excellent durability and selectivity for NH3 over a wide range of potentials in NO3−RR, surpassing the electrocatalytic performance of both undoped shell and core components. The outstanding performance Cu─CoO/Co(OH)2 is ascribed to the enhanced charge transfer, stabilization of key reaction intermediates, and regulation of hydrogen adsorption over Cu‐doped core/shell structure. Furthermore, the assembled Zn−NO3− battery device attains a peak current density exceeding 32 mA cm−2 and an NH3 yield of up to 145.4 µmol h−1 cm−2. The work offers a novel core/shell engineering strategy in electrocatalytic NO3−RR and sheds light on the doping effects on the electrochemical NH3 synthesis.

Photocatalytic activation of peroxymonosulfate by Ti-oxo clusters grafted carbon nitride: Enhanced charge transfer and bisphenol A degradation efficiency

Photocatalytic peroxymonosulfate (PMS) activation process is promising for the organic wastewater treatment. A simple amide bonding strategy has been developed to synthesized Ti-oxo clusters (TiOCs)-g-C3N4 (TiOCs-CN) catalyst. The prepared TiOCs-CN was used to remove bisphenol A (BPA) under simulated sunlight-driven PMS. The experimental and computational results demonstrate that the incorporation of TiOCs can efficiently regulate the electronic structure of CN. Thus, an excellent performance with a BPA removal rate of 100 % and a totalorganic carbon(TOC) removal rate of 87.2 % within 40 min was achieved in the AM 1.5/PMS-TiOCs-CN system.Among, the reaction rate constant of AM 1.5/PMS-TiOCs-CN (97.24 × 10−3 min−1) is higher than that of AM 1.5/PMS-CN (25.10 × 10−3 min−1) by nearly 4 times. The synergistic effect of photocatalytic PMS activation greatly facilitated the generation of reactive radicals and obviously increased the removal rate of BPA. This work can offer inspiration for rational design of high efficiency photocatalysts in the PMS oxidation process for organic wastewater remediation.

Separator engineering: Assisting lithium salt dissociation and constructing LiF-rich solid electrolyte interphases for high-rate lithium metal batteries

Challenges associated with lithium dendrite growth and the formation of dead lithium significantly limit the achievable energy density of lithium metal batteries (LMBs), particularly under high operating current densities. Our innovative design employs a state-of-the-art 2500 separator featuring a meticulously engineered cellulose acetate (CA) coating (CA@2500) to suppress dendrite nucleation and propagation. The CO functional groups in CA enhances charge transfer kinetics and triggering the decomposition of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), which leads to the formation of a more robust solid electrolyte interphase (SEI) composed primarily of LiF. Moreover, the introduction of polar functional groups in the CA enhances the separator’s hydrophilic properties, facilitating the uniform Li+ flux and creating a conductive pathway for efficient lithium migration. As a result, the CA@2500 separator exhibits a high lithium-ion transfer number (0.88) and conductivity. The lithium symmetric cell assembles with the CA@2500 separator displays a stable cycling performance over 5500 h at a current density and capacity of 10 mA cm−2 and 10 mAh cm−2, respectively. Additionally, LPF battery with CA@2500 separator shows an excellent capacity retention at 0.2 C with an average decay of 0.055 % per cycle. Moreover, a high capacity of 105 mAh g−1 is maintained after 500 cycles at 5 C with an average decay of only 0.027 % per cycle. This work achieved high stability of LMBs through simplified engineering.

Co(PO3)2@CoP Heterojunction in CoPO/GC/NF Nanoarrays Modulate Proton Hydrogen-Promoted Electrocatalytic Hydrodechlorination.

Cobalt phosphide has received much attention as an efficient catalyst for electrocatalytic hydrodechlorination (EHDC). However, the active species proton hydrogen (H*) is consumed by the hydrogen evolution reaction (HER). Herein, we report a crystal regulation strategy for cobalt phosphate/graphitic nanocarbon/nickel foam (CoPO/GC/NF) catalysts applied for the EHDC of 2,4-dichlorophenoxyacetic acid (2,4-D). Characterization revealed that during the high-temperature phosphatization process, CoPO/GC/NF catalysts developed Co(PO3)2@CoP heterojunctions, enhancing charge transfer at the electrolyte-catalyst interface and water dissociation. The interaction between Co(PO3)2 and CoP induced the reconstitution of CoP into the Co-OH species, which facilitated the production of H* by accelerating the Volmer step, enhancing EHDC activity. Furthermore, Co(PO3)2 species improve the catalyst tolerance, with CoPO/GC/NF(450) maintaining over 71% yield of phenoxyacetic acid (PA) in continuous testing for up to 80 h under high-salt conditions. This work clarifies the surface transformation process of CoP/GC/NF during hydrodechlorination and demonstrates great potential for chlorophenol wastewater remediation.

FeNiCo@lyocell-based carbon cloth cathode for enhanced seawater electrolysis with bipolar membrane

The formation of inorganic precipitates at the cathode is the most persistent problem in direct seawater electrolysis (DSWE) for hydrogen production. To address this issue, we demonstrate the combination of lyocell-based carbon cloth (CC, as a conductive substrate) and bipolar membrane (BPM)-based DSWE. The entire process, from fabricating lyocell-based CC to coating FeNiCo catalysts, is conducted to ensure stable adhesion between the CC surface and electrocatalysts, thereby enhancing charge transfer. The hydrogen evolution reaction activity of FeNiCo@lyocell-based CC in 1.0 M NaOH shows the overpotential of 152 mV at 10 mA/cm2, which is much lower than that (342 mV) of bare lyocell-based CC. When the FeNiCo@lyocell-based CC is used as a cathode in the BPM-DSWE, the growth rate of inorganic precipitates formed at the cathode is significantly reduced. As a result, the rate of increase in cathodic potential over 100 h at 100 mA/cm2 is approximately 6 %, which is more than four times smaller than that of Pt-coated Ti foam. The woven structure of the lyocell-based CC provides small holes densely distributed at regular intervals and empty spaces between carbon fibers arranged in the same direction. The unique structure is expected to help the protons generated from the BPM escape directly into bulk seawater. In this process, free protons can play a role in reducing the high pH formed at the interfaces of each fiber, slowing down the growth rate of inorganic deposits. If the empty space ratio of the porous structure and the three-dimensional connectivity are optimized for BPM-DSWE, lyocell-based CC is expected to be a promising conductive substrate that can suppress the formation of inorganic deposits even at higher current densities.

Tuning oxygen vacancies via photoinduced defect engineering in plasma pre-treated TiO2 for efficient solar-light-driven oxidation of trace methane

Photocatalysis employing cost-effective commercial titanium dioxide offers an ideal solution for eliminating trace methane emissions from livestock and poultry farming. However, significant challenges such as the rapid recombination of photogenerated carriers, a limited light absorption spectrum, and weak adsorption capabilities considerably hinder the effectiveness of titanium dioxide in the photocatalytic treatment of trace methane. This study proposes a novel approach to activate plasma pre-treated N-doped commercial anatase TiO2 into dual-defect TiO2 (N-doped TiO2-x) featuring stable and controllable oxygen vacancies (OV) through photoinduced defect engineering. Characterizations of the photocatalyst confirm the successful creation of surface defects, further evaluated through solar-light-driven CH4 (ppm level) removal investigations. The yield of this N-doped TiO2-x in converting CH4 is 4.84 μmol h−1, 44 times greater than that of unmodified TiO2, significantly outperforming previous studies. UV–Vis diffuse reflection spectra, and photoluminescence indicate that the modified commercial anatase TiO2 possesses a narrower band gap, efficient photogenerated carrier separation, and enhanced charge transfer. Furthermore, density functional theory (DFT) calculations demonstrate that the synergistic effects of oxygen vacancies and N doping enhance the adsorption and activation of both O2 and CH4 in the rate-determining step of the reaction. This innovative strategy holds considerable promise for modifying various materials for more efficient photocatalytic applications.

Uniform Molecular Adsorption Energy‐Driven Homogeneous Crystallization and Dual‐Interface Modification for High Efficiency and Thermal Stability in Inverted Perovskite Solar Cells

AbstractInterfacial defects between perovskite and adjacent charge transport layers present a significant obstacle, hindering the enhancement of power conversion efficiency (PCE) and stability in perovskite solar cells (PSCs). To address this challenge, a dual‐interface modification is proposed to aim at improving the performance of mixed‐halide PSCs. Specifically, the hole‐collecting side is modified with 5‐Aminopyridine‐2‐carboxylic Acid (APC), while the electron‐collecting side is modified with 2‐thiopheneethylammonium chloride (TEACl). The multifunctional APC enhances charge transfer by tailoring the interface between the perovskite and poly(triarylamine) (PTAA) through multiple bonding interactions, thereby suppressing interfacial nonradiative recombination. Density functional theory studies reveal that APC on the perovskite surface induces uniform adsorption energy, promoting homogenous crystallization without residual stress. Additionally, APC interlayer eliminates the localized edge states induced by the iodine vacancies near the conduction band edge. Further improvement in the device performance is achieved by passivating the top perovskite surface with TEACl, leading to well‐matched energy bands and reduced vacancy trap states. As a result, champion cell achieves a PCE of 24.87% with an open‐circuit voltage of 1.188 V. Furthermore, The dual‐interface modification improves thermal stability due to enhanced ion‐migration activation energy.

Boosted photo-Fenton-like process for selective degradation of emerging contaminants by dehydrated Fe-based metal–organic framework with thermodynamically-favorable center metal electron density and confinement effect

The Heterogeneous Fenton reaction has long stood out as a highly effective technology for water purification. However, it is nowadays facing challenges such as low selectivity, sluggish Fe(III) reduction, and limited H2O2 conversion efficiency. Herein, dehydrated MIL-100(Fe)-250 was synthesized through thermal treatment, demonstrating superior efficiency in removing emerging contaminants, with a three-fold efficiency higher than undehydrated sample. The dehydrated MIL-100(Fe)-250 exhibited selective acceleration in the removal of quinolones and phenolic organics, rendering the system resistant to interference from coexisting matter. Through in-situ diffuse reflectance infrared Fourier-transform spectroscopy and density functional theory calculation, it was manifested that dehydration process regulates the steric hindrance and local electron density of Fe ions. This adjustment enhances charge transfer, thereby facilitating Fe(III) reduction and promoting the H2O2 activation and conversion efficiency. Moreover, the quasi-steady-state concentrations of hydroxyl radical in MIL-100(Fe)-250 were found to be 2.2 times higher than that those in undehydrated sample. Impressively, the dehydrated MIL-100(Fe)-250 displayed adaptability across a broad pH range of 5.0–9.0. The present study underscores the significant potential of porous MIL-100(Fe)-250 with spatial confinement, which imparts a clear size exclusion effect. As a result, this catalyst emerges as a promising candidate for eliminating contaminants in real water matrices, offering a viable strategy for water pollution control.

Preparation and performance of graphene-doped indium tin oxide coatings on titanium bipolar plate surface

To enhance the corrosion resistance of titanium bipolar plates, indium tin oxide (ITO) coatings doped with varying quantities of graphene were fabricated using the sol-gel method. The coatings' surface morphology and microstructure were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The hydrophobicity of the coatings was evaluated using a contact angle goniometer, and their corrosion resistance in a simulated proton exchange membrane fuel cell (PEMFC) corrosion solution (0.5 mol/L H2SO4 + 2 mg/L HF) was measured using an electrochemical workstation. The findings revealed that increasing graphene doping resulted in a more uniform, smooth, and dense coating surface. The ITO coating primarily consisted of In2O3. However, with graphene doping, diffraction peaks of the InOCl phase appeared, indicating changes in the material's composition and structure. Additionally, the valence peaks of the main elements shifted, reflecting alterations in their chemical states. Graphene doping significantly enhanced the coating's hydrophobicity compared to the undoped ITO coating. The water contact angle of the ITO coating with 0.375 g/L graphene increased from 104° to 126°. Furthermore, this graphene-doped coating demonstrated superior corrosion resistance, with a corrosion current density of 0.06 μA/cm2, representing a decrease by three orders of magnitude compared to the titanium substrate. Additionally, it exhibited the largest capacitive arc radius, indicating enhanced charge transfer resistance and better overall electrochemical stability.

Transition Metal Oxide/Sulfide on the Ni Foam for Electrocatalytic UOR & OER

Water electrolysis is an important technology related to the energy conservation, is a promising technology. Currently, one of the key efforts is to improve the efficiency and reduce the cost of water electrolysis, in particular, the anodic oxygen evolution reaction (OER). Nobel-metal free OER catalyst or alternative urea oxidation reaction (UOR) is thus favored. Due to the advantages of enhance charge transfer and desirable charge redistribution, we have investigated nobel-metal free transition metal oxide/sulfide heterostructure UOR electrocatalyst. Co-Ni based metal heterostructure is synthesized using a simple two-step hydrothermal method. The resulting samples are examined using X-ray diffractometer, Scanning electron microscopy, X-ray photoelectron spectroscopy and the Inductively coupled plasma will used as the material analysis. Electrochemical performance is evaluated using linear sweep voltammetry, electrochemical impedance spectroscopy, cyclic voltammetry, and electrochemical active surface area. Moreover, the electrocatalyst is also evaluated as OER catalysts. The relation between the material characteristics and the electrochemical performance is discussed.