Interfacial Charge Transfer Resistance Research Articles

Molecular-Level Pore Tuning in 2D Conductive Metal-Organic Frameworks for Advanced Supercapacitor Performance.

Two-dimensional (2D) electrically conductive metal-organic frameworks (MOFs) have emerged as viable candidates for active electrode materials in supercapacitors due to their high electrical conductivity, high specific surface area, and intrinsic redox-active sites. Despite their promising electrochemical performance, their pseudocapacitive behavior via fast and reversible charge transfer reactions remains yet to be fully exploited. Here, we investigate the electrochemical energy storage mechanism of Cu3(HHTATP)2 (HHTATP = 2,3,6,7,10,11-hexahydroxy-1,5,9-triaminotriphenylene), a 2D conductive MOF featuring characteristic redox-active pendant aromatic amines. Cu3(HHTATP)2 exhibited pseudocapacitive charge storage with an average gravimetric capacitance of 340 ± 15 F g-1 at a discharge rate of 0.2 A g-1 and maintained a capacitance retention over 90% after 7000 galvanostatic cycles at 5 A g-1. The polar pendant amines not only enhanced capacitance via additional amine/imine redox activity but also reduced interfacial charge transfer resistance through modified electrode-electrolyte interactions. These results highlight the potential of molecular-level pore environment tuning as a strategic approach in materials design for energy storage applications.

Fabrication of pyridine incorporated and O-doped g-C3N4/COF: A type-II heterojunction for enhanced hydrogen production under visible light irradiation

The fabrication of heterojunction photocatalysts is important for achieving highly efficient electron transfer, charge separation, and catalytic activity. In this study, we report the successful creation of a type II heterojunction between pyridine incorporated and O-doped g-C3N4 (POCN) and a covalent organic framework (COF). The heterojunction formation significantly reduced the fluorescence intensity of the POCN/COF, indicating effective separation of electron-hole pairs. Additionally, POCN/COF demonstrated excellent interface charge transfer resistance and photocurrent response. Its hydrogen production rate was remarkably high at 3500 μmol g⁻1 h⁻1, about 1.6 times that of pure COF (2200 μmol g⁻1 h⁻1) and 3.5 times that of the physical mixture (1000 μmol g⁻1 h⁻1), and it also exhibited enhanced stability. This indicates that it can be effectively fabricated into a heterojunction of POCN and COF. The optimal value for adding POCN was approximately 5 wt% of COF. This demonstrates greater activity compared to other composite catalysts made from graphitic carbon nitride and COF. This study presents a valuable approach for fabricating reusable heterojunction photocatalytic systems and efficiently generating hydrogen from natural energy sources.

Eliminating Charge Transfer at Cathode-Electrolyte Interface for Ultrafast Kinetics in Na-Ion Batteries.

Sodium-ion batteries suffer from kinetic problems stemming from sluggish ion transport across the electrode-electrolyte interface, causing rapid energy decay during fast-charging or low-temperature operation. One exciting prospect to enhance kinetics is constructing neuron-like electrodes that emulate fast signal transmission in a nervous system. It has been considered that these bioinspired designs enhance electron/ion transport of the electrodes through carbon networks. However, whether they can avoid sluggish charge transfer at the electrode-electrolyte interface remains unknown. By connecting the openings of carbon nanotubes with the surface of carbon-coated Na3V2O2(PO4)2F cathode nanoparticles, here we use carbon nanotubes to trap Na+ ions released from the nanoparticles during charge. Therefore, Na+ movement is confined only inside the neuron-like cathode, eliminating ion transport between the electrolyte and cathode, which has been scarcely achieved in conventional batteries. As a result, a 14-fold reduction in interfacial charge transfer resistance is achieved when compared to unmodified cathodes, leading to superior fast-charging performance and excellent cyclability up to 200C, and surprisingly, reversible operation at low temperatures down to -60 °C without electrolyte modification, surpassing other Na3V2O2(PO4)2F-based batteries reported to date. As battery operation has relied on charge transfer at the electrode-electrolyte interface for over 200 years, our approach departs from this traditional ion transport paradigm, paving the way for building better batteries that work under harsh conditions.

Interface coupling to improve O2 adsorption and accelerate charge separation for boosting photocatalytic performance of ZnO/ZnIn2S4 composite in H2O2 production and environmental remediation

The key to heterogeneous photo-Fenton technology lies in the efficient generation of hydrogen peroxide (H2O2). Herein, a newly-designed ZnO/ZnIn2S4 composite with heterostructure is synthesized. Benefiting from the formation of built-in electric field, the recombination of photoinduced electrons and holes is suppressed and interfacial charge transfer resistance is reduced. Importantly, the embedding of ZnO in ZnIn2S4 can improve the hydrophobicity and create microscopic three-phase interface, thereby boosting the capture capability for O2 and providing the convenience for the occurrence of O2 reduction reaction. More interestingly, the existence of ZnIn2S4 in the ZnO/ZnIn2S4 composite can reduce the Gibbs free energy (ΔG) of key intermediate (OOH*) formation, which will accelerate the generation of H2O2. As a result, the ZnO/ZnIn2S4 composite displays excellent performance in photocatalytic H2O2 production, and the highest yield was about 897.6 μmol/g/h within 60 min under visible light irradiation. The transfer of photoinduced carriers follows the S-scheme type mechanism. The photogenerated holes can be captured by drug residues (i.e., diclofenac sodium) to accelerate H2O2 production, while generated H2O2 can combine with Fe2+ to construct photo-Fenton system for achieving the advanced degradation of diclofenac sodium, which was mainly related to the formation of OH•. Furthermore, generated H2O2 can be applied for performing the inactivation of pathogenic bacteria. In short, current work will provide a valuable reference for future research.

Synergistic engineering of heterojunction and surface coating to boost Zn storage performance of V2O3-based microspheres as an advanced cathode for aqueous zinc-ion batteries

Vanadium-based compounds are highly regarded as potential cathodes for aqueous zinc-ion batteries (AZIBs) owing to the high theoretical capacity, diverse structural frameworks and abundant oxidation states. Nevertheless, the challenges such as slow diffusion kinetics, low electrical conductivity and inadequate structural stability restrict their further development. Herein, yolk shell-like SiO2-coated V2O3/VN heterojunction microspheres (VON@SiO2) are synthesized through a hydrothermal method followed by annealing and subsequent SiO2 coating. As an advanced cathode for AZIBs, the construction of V2O3/VN heterojunction effectively exposes reactive sites, leads to the reduction in interfacial charge transfer resistance, and thus improves the ion diffusion kinetics, while the surface coating of SiO2 is beneficial for enhancing the structural stability of the material and further reduces the capacity fading. Additionally, the micromorphology of porous yolk shell-like microspheres self-assembled by nanoparticles contributes to the complete penetration of electrolyte and greatly exposing reactive sites. Based on synergistic engineering of heterojunction, surface coating and porous shell-like micromorphology, the synthesized VON@SiO2 delivers excellent specific capacities of 483.5 mAh g−1 at 0.5 A g−1 and 294 mAh g−1 at 10 A g−1, and exhibits impressive cycling performance with 94 % of capacity retention after 1000 cycles at 10 A g−1. Further, in-situ XRD and ex-situ XPS reveals the mechanism of zinc ion storage. This work offers a valuable reference into the development of high-performance cathode materials for AZIBs by co-engineering of heterojunction, surface coating and micromorphology optimization.

Interfacial studies of Cu2O/TiO2 junction deposited at different electropotentials

Based on the simplistic two-step preparation method, a Cu2O/TiO2 junction was synthesized by electrodepositing a Cuprous Oxide layer on Titanium Oxide thin films at different deposition potentials. The thin films and junction were characterized for their structural, morphological, optical, and electrical properties using X-ray diffraction, Scanning Electron Microscopy, UV–visible spectroscopy, and Electrochemical Impedance Spectroscopy. The XRD analysis of the Cu2O/TiO2 junction indicated no sharp diffraction peaks of TiO2, only Cu2O peaks were observed. The Scanning Electron Microscopy also demonstrated that the Cuprous Oxide thin films possessed three-sided pyramidal structures on their surface. The band gaps of Cu2O and TiO2 thin films were calculated as 2.2 eV and 3.3 eV respectively by using Tauc’s plots. Electrochemical impedance spectroscopy revealed reduced interfacial charge transfer resistance and a boost in charge carrier generation in fabricated junctions (grown at −0.6 V). The flat band potentials and carrier concentrations of the fabricated thin films and their junction were calculated using Mott-Schottky analysis. Meanwhile, charge transfer resistance, solution resistance, constant phase element, and other circuit parameters of the electrochemical cell were studied using Nyquist plots.

Deciphering the structural and kinetic factors in lithium titanate for enhanced performance in Li+/Na+ dual-cation electrolyte

The widespread application of Li4Ti5O12 (LTO) anode in lithium-ion batteries has been hindered by its relatively low energy density. In this study, we investigated the capacity enhancement mechanism of LTO anode through the incorporation of Na+ cations in an Li+-based electrolyte (dual-cation electrolyte). LTO thin film electrodes were prepared as conductive additive-free and binder-free model electrodes. Electrochemical performance assessments revealed that the dual-cation electrolyte boosts the reversible capacity of the LTO thin film electrode, attributable to the additional pseudocapacitance and intercalation of Na+ into the LTO lattice. Operando Raman spectroscopy validated the insertion of Li+/Na+ cations into the LTO thin film electrode, and the cation migration kinetics were confirmed by ab initio molecular dynamic (AIMD) simulation and electrochemical impedance spectroscopy, which revealed that the incorporation of Na+ reduces the activation energy of cation diffusion within the LTO lattice and improves the rate performance of LTO thin film electrodes in the dual-cation electrolyte. Furthermore, the interfacial charge transfer resistance in the dual-cation electrolyte, associated with ion de-solvation processes and traversal of the cations in the solid-electrolyte interphase (SEI) layer, are evaluated using the distribution of relaxation time, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Our approach of performance enhancement using dual-cation electrolytes can be extrapolated to other battery electrodes with sodium/lithium storage capabilities, presenting a novel avenue for the performance enhancement of lithium/sodium-ion batteries.

Hydrothermal preparation of a novel indium doped MoO3 photocatalyst with enhanced photocatalytic activity for Rhodamine B degradation

In this work, a simple one-step hydrothermal approach was used to successfully manufacture a novel indium doped molybdenum trioxide (In–MoO3) photocatalyst for enhancing the photocatalytic degradation of Rhodamine B (RhB) under simulated light. The structural characterization of In–MoO3 confirms successful addition of indium ions to the MoO3 lattice. Importantly, the performance of the doped samples was significantly enhanced when the doping mass of indium accounted for 5 % under simulated light, and the RhB degradation rate reached 96.2 %. Even after four cycles, the doped sample proved to maintain excellent cycling stability. The proposed photocatalytic mechanism for the RhB degradation by In–MoO3 is presented. It is revealed that ·OH acts as the primary active species in this photocatalytic system, while ·O2− also plays a supporting role. Indium doping improves the light absorption and effectively reduces the interfacial charge transfer resistance and bandgap width, leading to significant progress in the photocatalytic performance of MoO3.

Effect of AZO seed layers on the ultraviolet photoresponse of Ag/ZnO NRs Schottky junctions

Al-doped ZnO (AZO) thin films with different layers were prepared by sol-gel method. The SEM, XRD and AFM for three layers thin films demonstrates high crystal quality and low roughness. ZnO nanorods arrays (NRs) with different AZO seed layers were fabricated using hydrothermal process, and the effect of AZO seed layers on the structural, optical, and electrical characteristics was investigated. When there are three AZO seed layers present, ZnO NRs exhibit fewer surface states, smaller interface charge transfer resistance (Rce = 6.1 × 103Ωand Rct = 6.6 × 106Ω), longer carrier lifetimes (τe = 4.0 ms), higher carrier concentration (ND = 4.73 × 1019 cm−3), and narrower depletion region width W = 3.1 nm. Under weak UV light 381 nm (5.68 mW/cm2) at a bias −0.5 V, Ag/ZnO NRs Schottky devices with three AZO seed layers display a comparatively strong responsivity 34.64 mA/W. Appropriate AZO seed layers are favorable for highly efficient ZnO NRs-based photoelectric conversion devices.

Remarkable improvement in photocatalytic activity of g-C3N4 for NO oxidation through surface hydroxylation

The nitrogen oxide emissions originating from combustion pose significant risks to the environment. Photocatalysis is considered an efficient and environmentally friendly strategy to alleviate this problem. Graphitic carbon nitride (g-C3N4) is regarded as one of the most promising organic photocatalytic materials for environmental purification. However, its small specific surface area, weak adsorption and high recombination rate of charge carriers result in low intrinsic photocatalytic activity. To overcome these obstacles, a hydrothermal treatment of dicyandiamide-derived g-C3N4 (DCN) at different temperatures (140–200 °C) was employed to enhance the photocatalytic activity for NO oxidation. The experimental results demonstrated a significant improvement in the photocatalytic oxidation removal rate of NO after a hydrothermal treatment. The optimal photocatalyst, DCN-180, treated at 180 °C, demonstrated the highest NO removal efficiency (65.0 %), which is twice the value of pristine DCN (32.5 %). Additionally, the formation of the toxic intermediate NO2 was effectively suppressed during the reaction. Photoelectrochemical tests revealed that DCN-180 exhibited higher photocurrent density and smaller impedance radius compared to the untreated g-C3N4 sample. Moreover, density functional theory (DFT) calculations confirmed that the DCN-180 sample showed a stronger ability to adsorb O2 and NO. The enhanced photocatalytic NO oxidation performance of DCN-180 has been primarily attributed to its enlarged specific surface area (from 10.7 to 35.5 m2 g−1), local polarization effect, reduced interfacial charge transfer resistance, and improved adsorption abilities for NO and O2 molecules. This study provides valuable insights for designing and preparing highly efficient g-C3N4 based photocatalysts through surface modification for photocatalytic NO purification.

Constructing High-Performance Cobalt-Based Environmental Catalysts from Spent Lithium-Ion Batteries: Unveiling Overlooked Roles of Copper and Aluminum from Current Collectors.

Converting spent lithium-ion batteries (LIBs) cathode materials into environmental catalysts has drawn more and more attention. Herein, we fabricated a Co3O4-based catalyst from spent LiCoO2 LIBs (Co3O4-LIBs) and found that the role of Al and Cu from current collectors on its performance is nonnegligible. The density functional theory calculations confirmed that the doping of Al and/or Cu upshifts the d-band center of Co. A Fenton-like reaction based on peroxymonosulfate (PMS) activation was adopted to evaluate its activity. Interestingly, Al doping strengthened chemisorption for PMS (from -2.615 eV to -2.623 eV) and shortened Co-O bond length (from 2.540 Å to 2.344 Å) between them, whereas Cu doping reduced interfacial charge-transfer resistance (from 28.347 kΩ to 6.689 kΩ) excepting for the enhancement of the above characteristics. As expected, the degradation activity toward bisphenol A of Co3O4-LIBs (0.523 min-1) was superior to that of Co3O4 prepared from commercial CoC2O4 (0.287 min-1). Simultaneously, the reasons for improved activity were further verified by comparing activity with catalysts doped Al and/or Cu into Co3O4. This work reveals the role of elements from current collectors on the performance of functional materials from spent LIBs, which is beneficial to the sustainable utilization of spent LIBs.

The insights into facet-dependent catalytic performance of Cu2O in peroxymonosulfate activation for effective degradation of antibiotics

It was of great significance to improve the performance of catalysts in peroxymonosulfate (PMS) activation for water pollution control. Herein, Cu2O-based catalysts with different exposed facets were synthesized by a feasible method, and later employed for activating PMS to conduct the degradation tests of tetracycline (TC). With the increase of exposed (100) facet, the specific surface area of Cu2O was improved and the interface charge transfer resistance was reduced. More interestingly, benefiting from the exposure of (100) facet, the electron-donating ability of Cu2O was boosted, and the adsorption energy of PMS over Cu2O was also reduced, thereby creating favorable conditions for PMS activation. As guessed, Cu2O-1 with (100) facet can quickly activate PMS to achieve the effective degradation of TC, and the highest removal efficiency of TC over Cu2O-1 can be up to 97.56 % within 15 min. Furthermore, Cu2O-1 with good anti-interference showed satisfactory reusability, and the degradation intermediates of TC were the low toxic or nontoxic. In the Cu2O-1/PMS system, various reactive oxygen species were detected, including SO4•–, OH•, O2•– and 1O2, and wherein the contribution of 1O2 to TC degradation was the greatest. In short, current work shared some valuable insights into persulfate-based advanced oxidation processes.

Covalently Linking Reduced Graphene Oxide Facilitated Electrodeposition of MoS2 on Silicon Pyramidal Photocathode To Enhance Hydrogen Evolution.

In recent years, increasing attention has been paid to photoelectrochemical (PEC) hydrogen production owing to the utilization of sustainable solar energy and its promising performance. Silicon-based composites are generally considered ideal materials for PEC hydrogen production. However, slow reaction kinetics and poor stability are still key factors hindering the development of silicon-based photoelectrocatalysts. Herein, we present an n+-p Si pyramidal photocathode assembly method to load reduced graphene oxide (rGO) onto the surface of the n+-p Si pyramid by covalently linking (Si/rGO). rGO is utilized as a conductive layer to reduce the interfacial charge-transfer resistance. Then, MoS2 can be successfully electrodeposited on the surface of Si/rGO to form the Si/rGO/MoS2 composite, which possesses excellent PEC hydrogen evolution performance with a high and stable photocurrent of -41.6 mA cm-2 and a hydrogen evolution rate of about 18.1 μmol min-1 cm-2 under 0 V (vs RHE). The covalently linking rGO layer effectively enhances the transfer of photogenerated carriers between the Si substrate and MoS2. MoS2 provides abundant hydrogen evolution active sites, which accelerate the surface reaction kinetics, as well as a protective layer for the Si pyramidal array structure. This work provides a low-cost, convenient, and efficient way of preparing silicon-based photocathodes.

Templated Growth of In2S3 in Ti3C2TX MXene with Enhanced Photocatalytic Properties

The growth of ultrathin semiconductors is advantageous for photocatalysis due to improved photophysical properties and reduced charge recombination. Along these lines, templating the growth of semiconductors in confined spaces can allow control over semiconductor growth while also conferring the properties of the template to provide composite nanomaterial hybrids. Herein, the semiconductor In2S3 is grown in the organically‐modified interlayer space of Ti3C2TX MXene, a versatile 2D material with metallic character and broadband light absorption. The growth of 1–2 nm thick layers of In2S3 in the interlayer of MXene leads to a drastic increase in photocatalytic properties and light‐induced charge generation due to decreased interfacial charge transfer resistance. Interestingly, the hydrothermal conditions of In2S3 growth lead to partial oxidation of Ti3C2TX MXene to form anatase TiO2 nanocrystals, although this effect is strongly limited by increased In2S3 precursors due to passivation of the MXene surface. MXenes serve as effective templates for the confined growth of semiconductors, emphasizing the potential of MXene as a template for 2D material heterostructures. Overall, this work further develops MXene‐based 2D material composites, offering insights into the origins of the enhanced photocatalytic and photoelectrochemical properties, toward improvements in energy production and aqueous phase catalysis.

Controllable preparation of TiO2 nanorod arrays for enhanced ultraviolet photoresponse performance of Au/TiO2 Schottky junction

The optical and electrical properties of semiconductors depending on the microstructure are crucial for the application in various optoelectronic devices. TiO2 nanorod arrays (NRs) were prepared by hydrothermal method, and the ultraviolet (UV) photoresponse performance of Au/TiO2 NRs Schottky junction device was studied. The morphology, crystal orientation and filminess of TiO2 NRs were modulated by a facile control strategy employing anhydrous ethanol as stabilizer. With the increase of the amount of anhydrous ethanol, the diameter of TiO2 NR gradually expanded and the length increased rapidly. The anhydrous ethanol promotes the growth of TiO2 NRs preferentially in the [001] direction and decreases the oxygen vacancy in the surface of TiO2 NRs. With 10 mL of anhydrous ethanol added, the device displays a high sensitivity (8.93 A/W) to weak 376 nm UV light (0.18 mW/cm2) at a bias of -1V. The highest carrier concentration, the longest electron lifetime, the lowest interfacial charge transfer resistance and series resistance resulted in the best UV photoresponse. The exploration of dynamics process of photogenerated carriers in Schottky junction can help to improve the performance of optoelectronic devices such as photodetectors and solar cells.

A novel synthetic strategy of mesoporous Ti4O7-coated electrode for highly efficient wastewater treatment

Suboxidized titanium, as a promising anode for electrocatalytic oxidation reactions in wastewater treatment, presents a viable pathway to solve the challenging water pollution. However, current suboxidized titanium anodes are primarily fabricated hot pressing of by suboxidized titanium powders, further hampering their application in wastewater treatment due to high costs and complex shaping processes. To overcome these limitations, this work employs the plasma electrolytic oxidation (PEO) technology to in-situ fabricate porous TiO2 coating precursors on commercial pure titanium substrates, followed by an annealing process to carefully reduce the TiO2 coatings with hydrogen gas, and finally achieving the cost-effective production of high-purity Magnéli phase Ti4O7-coated electrode. The obtained Ti4O7-coated electrodes exhibit a highly ordered granular structure, good crystallinity, wide electrochemical window, and low interfacial charge transfer resistance. Importantly, the Ti4O7-coated electrodes also offer a simple fabrication process, lower energy consumption, and reduced costs compared to advanced boron-doped diamond (BDD) and bulk Ti4O7 electrode. The electrochemical oxidation tests also demonstrate that Ti4O7-coated electrodes can achieve the complete degradation of 100 mg/L phenol within 240 minutes, exhibiting excellent catalytic activity and potential applications in wastewater treatment.

Photoactive cationic conjugated microporous polymers containing pyrimidine with an ‘adsorption-kill’ antibacterial strategy for infected wound healing

Pathogenic bacterial invasion leads to severe inflammation that hinders wound healing, and it has become a major medical threat worldwide. Photodynamic therapy (PDT) has emerged as a promising strategy for treating microbial infection; however, developing a dressing with PDT effect and excellent biological functions poses a formidable challenge. Herein, a novel cationic pyrimidine-modified conjugated microporous polymer, BPyMe-CMP, was rationally designed and synthesized via a Sonogashira-Hagiwara and SN2 substitution reaction. The BPyMe-CMP exhibited weak interfacial charge transfer resistance and demonstrated superior photoinducible carrier separation, thereby displaying an excellent photoelectric response. Consequently, the BPyMe-CMP could readily generate reactive oxygen species under visible light irradiation to kill bacteria. In addition to enhancing the photogenerated electron transfer process, BPyMe-CMP also provided abundant attraction sites for bacteria to reinforce the antibacterial ability. The deposition of BPyMe-CMP onto polyvinyl alcohol-modified silk fibroin (SF/PVA) film served as a wound dressing to promote healing. The in vitro and in vivo experiments revealed that the SF/PVA@BPyMe-CMP induced M2-type macrophage polarization, promoted L929 fibroblast migration, exhibited bactericidal activity, and induced angiogenesis, which synergistically accelerated the healing of methicillin-resistant Staphylococcus aureus-infected wounds. This study provides data support to advance the construction of a multi-functional wound dressing based on pyrimidination and cationization for the treatment and rapid healing of infected wounds.

Temperature effect on n-Si/Fe/NiFe photoanodes for the high-efficiency PEC water splitting

Sunlight-driven photoelectrochemical cell (PEC) can utilize water for high-efficiency artificial photosynthesis to produce low-cost green hydrogen fuel. It is crucial to explore the factors affecting the efficiency of PEC water splitting. The ambient temperature of the electrode is yet an important factor that influences PEC performance. Here, n-Si/Fe/NiFe composite photoanodes prepared by electrodeposition exhibited a low onset potential of 0.87 V and a high photocurrent density of 29.70 mA cm−2 (1.23 V vs. RHE) at room temperature, which is superior to those of n-Si/Fe and n-Si/NiFe. The influence of the temperature on the photoelectrochemical properties of n-Si/NiFe was systematically investigated. As the temperature increased, the photocurrent density of n-Si/Fe/NiFe decreased gradually and the oxidation reaction slowed down. Further experiments showed that raising the temperature helps to reduce the interfacial charge transfer resistance, increase the redox potential and carrier density. However, increasing the temperature also increases the recombination rate of photo generated carriers, reduces the carrier lifetime, and thus lowers the performance of PEC. Therefore, adjusting the ambient temperature is a potential method to improve the photoelectrochemical performance of silicon-based photoanodes.

Effective Activation of Peroxymonosulfate by Oxygen Vacancy Induced Musa Basjoo Biochar to Degrade Sulfamethoxazole: Efficiency and Mechanism.

Biochar materials have garnered attention as potential catalysts for peroxymonosulfate (PMS) activation due to their cost-effectiveness, notable specific surface area, and advantageous structural properties. In this study, a suite of plantain-derived biochar (MBB-400, MBB-600, and MBB-800), possessing a well-defined pore structure and a substantial number of uniformly distributed active sites (oxygen vacancy, OVs), was synthesized through a facile calcination process at varying temperatures (400, 600, and 800 °C). These materials were designed for the activation of PMS in the degradation of sulfamethoxazole (SMX). Experimental investigations revealed that OVs not only functioned as enriched sites for pollutants, enhancing the opportunities for free radicals (•OH/SO4•-) and surface-bound radicals (SBRs) to attack pollutants, but also served as channels for intramolecular charge transfer leaps. This role contributed to a reduction in interfacial charge transfer resistance, expediting electron transfer rates with PMS, thereby accelerating the decomposition of pollutants. Capitalizing on these merits, the MBB-800/PMS system displayed a 61-fold enhancement in the conversion rate for SMX degradation compared to inactivated MBB/PMS system. Furthermore, the MBB-800 exhibited less cytotoxicity towards rat pheochromocytoma (PC12) cells. Hence, the straightforward calcination synthesis of MBB-800 emerges as a promising biochar catalyst with vast potential for sustainable and efficient wastewater treatment and environmental remediation.

Controllable synthesis of Ag2Se binary thin-film via electrochemical atomic layer epitaxy (ECALE) and its characterization

Herein, synthesis of Ag2Se nanofilms was attempted for the first time at room temperature using electrochemical atomic layer epitaxy (ECALE) in underpotential deposition (UPD) basis. Spectrochemical/electrochemical measurements verified a 2-D growth for the Ag–Se films when the deposition potentials were gradually adjusted to negative (−1 mV/cycle). Electrochemical impedance spectroscopy (EIS) measurements illustrated less interfacial charge transfer resistance at the nanofilm coated surface. Scanning electron microscope (SEM) indicated that the film was composed of crystallites with size of around 110 nm. Energy dispersive X-ray spectroscopy (EDS) analyzes verified the 2:1 stoichiometric ratio for the compound and X-ray diffraction (XRD) analysis confirmed an orthorhombic β-Ag2Se crystalline phase. Ultraviolet–visible (UV–Vis) absorption measurements were performed to estimate the band gap of Ag2Se thin-film. Contact angle (CA) measurements demonstrated a decreased surface wettability. The proposed ECALE approach offered a low-cost and a facile method for the synthesis of epitaxial Ag2Se nanofilms that could be controlled at the atomic level.