Lower Adsorption Energy Research Articles

Neurotransmitter amino acid adsorption on metal doped boron nitride nanosheets as biosensor: DFT study on neural disease prediagnosis system

In this study, pristine and iron (Fe), copper (Cu) and platinum (Pt) metal doped boron nitride nanosheet (BNNS) structures possibility of biosensor, adsorbent and neural disease prediagnosis system for gama amino butyric acid (GABA) and Glutamate (Glu) molecules were investigated by Density Functional Theory (DFT). Metal atoms were doped to replace both boron (B) and nitrogen (N) atoms of BNNS. All the adsorption energies on the structure were calculated as negative values for all structures after the GABA and Glu adsorption. The lowest adsorption energy and enthalpy values reached to − 42.1 kcal/mol and − 42.7 kcal/mol, respectively. According to Gibbs free energy (∆G) values of adsorption, most of the adsorption reactions can occur spontaneously. The charge transfer during adsorption happened from GABA and Glu molecules to BNNS structures. Based on the results, Fe-doped BNNS and Cu-doped BNNS could be utilized as electronic and work function type biosensors for GABA molecule and Glu molecule respectively. This study may lead to future biosensor studies, adsorption studies of neurotransmitter amino acids other than GABA and Glu, and BN nanostructure studies modified with different metal doping.

Enhanced ability of toluene oxidation by controlling inversion degree of spinel composed of only Co, Mn

Exploring the single relationship between the inversion degree of spinel and its catalytic performance is a great challenge, but has important significance for further structural design and application. A series of CoMn inverse spinels were prepared and the general formula Co1-x2+Cox3+tetMn13+Cox2+Co1-x3+octO4 was deduced through X-ray diffraction refinement to find a decreased inversion degree x as calcination temperature rose. Catalytic oxidation of toluene showed that higher inversion degree (S-300 with x ≈ 0.95) can reach larger conversion rate (90 % at about 250 °C for 400 ppm toluene) with greater reaction stability (140 h). Density Functional Theory (DFT) calculations on density of states indicated its metallic nature, and found that the strength of O-p and Transition metal-d orbitals at Fermi energy is positively correlated to the inversion degree, meaning stronger electron migration ability. Along with the adsorption calculation analysis that lattice oxygen species are proved to work dominantly (S-300 with lowest adsorption energy but highest performance), this work uncovered a theoretical insight into inverse spinel oxide, to provide the possibility of elevated oxidation ability through structural control.

A DFT study the role of pristine and metal doped of g-CN nanosheet for drug delivery system

This research focuses on investigating how a targeted drug delivery system (DDS) can improve distribution and bioavailability of a drug on tumor cells. Specifically, study examines the use of pristine and Al-doped graphitic carbon nitride (C3N) sheets as the delivery system. By employing density functional theory (DFT), researchers analyze interaction between anticancer drug cisplatin (Cis) and sheets. Results demonstrate that doping process modifies characteristics of pristine sheets, leading to improved adsorption of anticancer drugs. Al-doped sheet exhibits a cohesive energy within range of 4.96 eV, indicating its high stability. Present work has uncovered that adsorption of Cis drug over pristine C3N sheet is weak, with low adsorption energy (Eads) values of approximately −3.26 eV and −2.19 eV in a gaseous (aqueous) phase, respectively. However, Eads is significantly enhanced by approximately 85.92 % through introduction of Al doping in pristine C3N sheet. Primary interactions within the complexes are examined employing non-covalent interaction (NCI) analysis, utilizing a reduced density gradient (RDG) map. Cis@Al-C3N complex reveals that non-covalent interactions have a significant role in drug adsorption. Moreover, NCI indicates van der Waals interactions exert a substantial impact on interaction between carrier sheets and anticancer drug. Present investigation sets foundation for future research focusing on utilization of doped C3N sheets as effective drug carriers in targeted DDSs, potentially benefiting a wide range of drugs.

(Keynote) Oxygen Reduction and Evolution Reactions on Faceted MnxCo1-XFe2O4 Nanoparticles Prepared By Induction-Coupled Plasma

Substantial research efforts are directed toward the development of precious metal-free catalysts for fuel cells, metal-air batteries and electrolyzers, because the deployment of these technologies requires the synthesis of low-cost catalysts with controlled properties in large quantities.Mixed spinel oxides are a promising class of catalytic materials for the oxygen evolution (OER) and oxygen reduction (ORR) reactions, and thus several works have been devoted to the understanding of the structure – composition – activity relationships. Examples include the correlation between activity of spinel oxides and the covalency of the bond formed between the oxygen species and the metal cation in the octahedral sites1, or the possible role of metal cations in the tetrahedral sites in the oxygen electrocatalysis2. However, studies highlighting the importance of the facet engineering on the electrocatalytic activity of spinel oxides3 are still rare.Here, we will present our recent work on facetted nanoparticles MnxCo1-xFe2O4 (0 ≤ x ≤ 1) prepared by thermal plasma induction; a one step4, cost-effective and scalable method allowing the synthesis of large amounts (up to 30 g h-1 for 50 kW units) of uniform and crystalline nanoparticles5.Structural characterization by X-ray diffraction and TEM-EELS analysis showed that the mixed ferrite nanoparticles are formed by individual nanocrystals with well-defined truncated octahedron shape and with {100} and {111} facets mainly exposed, have high crystallinity, a median particle size of 40 nm and a homogeneous composition down to the atomic level.Electrochemical studies conducted in 0.1M KOH using the rotating disk electrode showed the highest activity was found for carbon black + Mn0.5Co0.5Fe2O4 composite electrode: half-wave potential for oxygen reduction 140 mV more negative than that of 20 wt% Pt/C; 420 mV oxygen evolution overpotential at 10 mAcm-2 (identical to IrO2/C). These are among the best performances reported for ferrites considering the size of the nanocrystals.Computational studies using density functional theory used to study the adsorption of oxygen molecule on the {100} and {111} facets of both CoFe2O4 and Mn0.5Co0.5Fe2O4 demonstrated that the Mn0.5Co0.5Fe2O4 {111} surface appears to have a highest affinity for the O2 molecule. The sites with lowest adsorption energy on each surface were identified and further analysis of O-O bond length and frequency as well as the Mulliken charge and populations confirmed the activation of the adsorbed O2 molecule. The energy diagrams of the ORR and OER computed for both Mn0.5Co0.5Fe2O4 {100} and {111} surfaces also pointed for a higher electrocatalytic activity for the {111} facet.

Adsorption of gas molecules on intrinsic and defective MoSi2N4 monolayer: Gas sensing and functionalization

The adsorption behaviors of CO, NH3, NO, and NO2 on intrinsic and defective MoSi2N4 monolayer, and the electronic properties, magnetic and gas sensing properties are researched by first-principles calculations. The low adsorption energies of gas molecules adsorbed on the intrinsic MoSi2N4 systems demonstrate that physisorption characteristics. The CO and NH3 adsorbed on MoSi2N4 systems exhibit non-magnetic semiconductor behavior, whereas the NO and NO2 adsorbed on MoSi2N4 systems emerge magnetic semiconductor behavior. The recovery time of the CO, NH3, NO, and NO2 adsorbed on MoSi2N4 systems is 1.70 × 10−11, 3.6 × 10−10, 2.60 × 10−11, and 3.21 × 10−10 s, respectively. Meanwhile, the sensitivities are 0.42 (CO), 0.41 (NH3), 0.51 (NO), and 0.27 (NO2) for the intrinsic MoSi2N4, respectively, demonstrating that MoSi2N4 can be an invertible sensor to detect CO, NH3, NO, and NO2 in the environment. Interestingly, the N defect MoSi2N4(VN/MoSi2N4) system displays magnetic semiconductor features, while the NO adsorbed VN/MoSi2N4 system has non-magnetic semiconductor feature. The Si defect MoSi2N4 (VSi/MoSi2N4) system appears magnetic semimetal characteristics, while the NH3 adsorbed VSi/MoSi2N4 system appears nonmagnetic semiconductor characteristics. Compared with the intrinsic MoSi2N4, the defect MoSi2N4 adsorption systems has stronger adsorption energy, suggesting that the stronger capture ability of the defect MoSi2N4 for CO, NH3, NO, and NO2.

H2 adsorption isotherms of Mg-MOF-74 isoreticulars: An integrated approach utilizing a thermochemical model and density functional theory

A thermochemical model was developed to calculate the H2 adsorption isotherm of theoriginal Mg-MOF-74 framework, and its computationally designed isoreticular employing the adsorption energies and vibrational frequencies obtained from density functional theory calculations as input variables. The model reasonably replicates the experimental adsorption isotherm of the original framework at -196oC within the pressure range up to 1 bar. The strongest adsorption site of the new Mg-MOF-74 isoreticular exhibits saturation at lower pressure compared to the original one, despite a lower adsorption energy. This emphasizes the importance of vibrational, rotational, and translational contributions for comprehensively assessing the site’s adsorption performance. Because only the strongest adsorption site was taken into account for the site-site interaction, the model is only valid for low coverage rates of secondary sites. Consequently, it strongly overestimates the hydrogen uptake of the original isoreticular at higher temperature and pressure ranges where the cumulative coverage rate of the secondary adsorption sites is comparable to that of the strongest sites. In contrast, the model remains valid for the new isoreticular at a specific temperature between -40oC and 60oC within the pressure range up to 25 bar where the coverage rate of the secondary adsorption site is low. Its predictions highlights the significantly improved performance of the new framework compared to the original framework. Specially, it achieves a gravimetric hydrogen uptake value between 2.8 wt% and 1.9 wt% at a pressure of 25 bar within the mentioned temperature swing which is substantially higher than that of the original framework.

High-sensitivity NH3 gas detection at room temperature using In2O3 nanoparticles-modified VO2(B) nanorods heterojunction

In2O3 nanoparticles-modified VO2(B) nanorods heterojunction was proposed to improve the NH3 sensing performance at room temperature (25 ℃). VO2(B) nanorods were prepared by hydrothermal method and modified with In2O3 nanoparticles through chemical deposition and annealing. The effect of annealing temperature on microstructure and NH3 sensing performance was investigated. The morphology and crystal structure of the composite structure were characterized using SEM, TEM, and XRD. The results show that In2O3 nanoparticles with a diameter of 20–25 nm were uniformly distributed on the surface of VO2(B) nanorods when the annealing temperature was 400 ℃. Room temperature NH3 sensing performance was tested for six concentrations (1–100 ppm). Results showed that samples annealed at 400 ℃ exhibited the highest sensitivity, with a response value of up to 92 for 100 ppm NH3. This excellent sensing performance can be attributed to the excitation of electrons in narrow bandgap semiconductor VO2(B) at room temperature and the surface modification by In2O3 nanoparticles, which promote the adsorption of surface oxygen. Density functional theory indicated the composite structure has lower NH3 adsorption energy compared to VO2(B) and In2O3. A possible sensing mechanism combined heterojunction effect with hydroxylization effect was proposed to explain the sensing enhancement for composite structure.

Mechanistic Study on the Possibility of Converting Dissociated Oxygen into Formic Acid on χ-Fe5C2(510) for Resource Recovery in Fischer-Tropsch Synthesis.

During Fischer-Tropsch synthesis, O atoms are dissociated on the surface of Fe-based catalysts. However, most of the dissociated O would be removed as H2O or CO2, which results in a low atom economy. Hence, a comprehensive study of the O removal pathway as formic acid has been investigated using the combination of density functional theory (DFT) and kinetic Monte Carlo (kMC) to improve the economics of Fischer-Tropsch synthesis on Fe-based catalysts. The results show that the optimal pathway for the removal of dissociated O as formic acid is the OH pathway, of which the effective barrier energy (0.936 eV) is close to that of the CO activation pathway (0.730 eV), meaning that the removal of dissociated O as formic acid is possible. The main factor in an inability to form formic acid is the competition between the formic acid formation pathway and other oxygenated compound formation pathways (H2O, CO2, methanol-formaldehyde); the details are as follows: 1. If the CO is hydrogenated first, then the subsequent reaction would be impossible due to its high effective Gibbs barrier energy. 2. If CO reacts first with O to become CO2, it is difficult for it to be hydrogenated further to become HCOOH because of the low adsorption energy of CO2. 3. When the CO + OH pathway is considered, OH would react easily with H atoms to form H2O due to the hydrogen coverage effect. Finally, the removal of dissociated O to formic acid is proposed via improving the catalyst to increase the CO2 adsorption energy or CO coverage.

Selective Anchoring by Surface Sulfur Species Coupled with Rapid Interface Electron Transfer for Ultrahigh Capacity Extraction of Uranium from Seawater.

Improving the adsorption selectivity, enhancing the extraction capacity, and ensuring the structural stability of the adsorbent are the key to realize the high efficiency recovery of uranium. In this work, we utilized the strong Lewis acid-base interaction between S2- and U(VI)O22+ coupling rapid electron transfer at the MnS/U(VI)O22+ solid-liquid interface to achieve excellent selectivity, high adsorption capacity, and rapid extraction of uranium. The as-synthesized MnS adsorbent exhibited an ultrahigh uranium extraction capacity (2457.05 mg g-1) and a rapid rate constant (K = 9.11 × 10-4 g h-1 mg-1) in seawater with 100.7 ppm of UO2(NO3)2 electrolyte. The kinetic simulation reveals that this adsorption process is a chemical adsorption process and conforms to a pseudo-second-order kinetic model, indicating electron transfer at the MnS/U(VI)O22+ solid-liquid interface. The relevant (quasi) in situ spectroscopic characterization and theoretical calculation results further revealed that the outstanding uranium extraction property of MnS could be attributed to the highly selective UO22+ adsorption of MnS with lower adsorption energy as a result of the strong interaction between S2- and UO22+ and the rapid mass transfer and interface electron transfer from S2- and low-valent Mn(II) to U(VI)O22+.

Cu- and Al-Decorated Monolayer TiSe2 for Enhanced Gas Detection Sensitivity: A DFT Study.

The rapid industrial development has contributed to worsening global pollution, necessitating the urgent development of highly sensitive, cost-effective, and portable gas sensors. In this work, the adsorption of CO, CO2, H2S, NH3, NO, NO2, O2, and SO2 gas molecules on pristine and Cu- and Al-decorated monolayer TiSe2 has been investigated based on first-principles calculations. First, the results of the phonon spectrum and ab initio molecular dynamics simulations demonstrated that TiSe2 is dynamically stable. In addition, compared to pristine TiSe2 (-0.029 to -0.154 eV), the adsorption energy of gas molecules (excluding CO2) significantly decreased after decorated with Cu or Al (-0.212 to -0.977 eV in Cu-decorated TiSe2, -0.438 to -2.896 eV in Al-decorated TiSe2). Among them, NH3 and NO2 have the lowest adsorption energies in Cu and Al-decorated TiSe2, respectively. Further research has shown that the decrease in adsorption energy of gas molecules is mainly due to orbital hybridization and charge transfer between decorated Cu and Al atoms and gas molecules. These findings suggest that TiSe2 decorated with Cu and Al can effectively improve its sensitivity to NH3 and NO2, respectively, making it promising in gas sensing applications.

MXenes quantum dots for efficient pesticide adsorbents: A first principal study of the adsorption capability

In the quest for environmental preservation, illness prevention, and food safety, the development of highly sensitive pesticide sensors is crucial. This study delves into the electronic properties, adsorption traits, reusability, and intermolecular interactions of Ti2C quantum dots and passivated Ti2C quantum dots regarding three hazardous pesticides: acetamiprid, atrazine, and bentazon. We explore both surface and edge configurations of these nanomaterials to assess their suitability for pesticide detection and removal. Adsorption energy estimates reveal the bond strength between quantum dots and pesticides. Ti2C quantum dots exhibit superior intermolecular bonding compared to Ti2CO quantum dots, promising efficient pesticide adsorption. Concerning reusability, Ti2CO quantum dots prove environmentally friendly and cost-effective due to their lower adsorption energy. Non-covalent interaction analysis unveils significant van der Waals and attractive non-covalent interactions between pesticides and the Ti2C substrate, shedding light on pesticide-nanomaterial complex stability.

Ultrasound and defect engineering-enhanced nanozyme with high laccase-like activity for oxidation and detection of phenolic compounds and adrenaline

Perusing metal-based redox nanozyme offers new opportunity for pollutant removal and biosensor, but ultrasound (US)-driven laccase-like nanozyme remains a significant challenge, especially in combination with defect engineering strategy. Herein, the Cu2Ov@Ce-TCPP was synthesized by doping Ce3+ on the surface of Cu2O nanocube and then coating with the porphyrin sonosensitizer. The Ce-doped porphyrin metal-structure in nanozyme was demonstrated to generate oxygen vacancy defects, which could obviously promote the laccase-like activity of Cu2Ov@Ce-TCPP nanozyme under US. XPS characterization and density functional theory (DFT) theoretical calculation revealed that the ultrasonic stimulation is beneficial to accelerate the electron transfer rate and O2 adsorption to improve catalytic activity, and Cu2Ov@Ce-TCPP nanozyme exhibits low adsorption energy and activation energy due to the presence of oxygen defect site, resulting in high laccase-like activity. The interaction between Ce atom and porphyrin structure also improved the sonocatalytic ability of the nanozyme. Meanwhile, Cu2Ov@Ce-TCPP nanozyme has been used for detecting and degrading a series of phenolic compounds. The detection adrenaline method has a linear range of 3.3–1000 μM and a detection limit as low as 0.96 μM with good reproducibility. The developed US-enhancing and recyclable laccase-like nanozyme system provides a promising strategy for the oxidation and detection of phenolic compounds.

Efficient fenton-like catalysis enabled by single cobalt atoms anchored on expanded graphite: Remarkable intrinsic activity of Co-N4 sites and the enhanced mass transfer facilitated by gradient mesopore structure

The single-atom catalysts derived from traditional Zeolitic Imidazolate Framework (ZIF) materials are exclusively characterized by a micropore structure, which severely hampers both the mass transfer efficiency and the accessibility of metal sites during catalysis. Herein, by utilizing mesoporous expanded graphite (EG) and ZIF-67 as precursors, a novel single-atom cobalt catalyst anchored on three-dimensional porous carbon materials (ZIF-67-x@EG) has been developed. Experiments demonstrate that introducing cobalt atoms in the formed bulges of EG increases carrier concentration and significantly enhances carrier mobility. The resulting ZIF-67-1@EG catalyst exhibits remarkable efficiency in degrading levofloxacin (LEVO concentration = 48 mg/L), with a degradation rate constant (0.078 min−1) 3.25 times higher than EG@N (0.024 min−1). The Co amounts in all ZIF-67-x@EG catalysts positively correlated with the reaction rate constant (R2 = 0.995). The ZIF-67-1@EG, with a small amount of cobalt loading (2.29 at%), exhibited an exceptionally high turnover frequency (TOF) value for LEVO (0.49 min−1). The degradation process involves an electron transfer pathway (ETP) and the contribution of singlet oxygen (1O2). The toxicity of the intermediates was characterized by quantitative structure-activity relationship (QSAR) prognostication, and the toxicity was reduced post-reaction. PMS/Co-N4 (-0.37 eV) and PMS/pyridinic N (-0.39 eV) configurations exhibit lower adsorption energies than PMS/pyrrolic N (-0.32 eV) structure, indicating that PMS primarily binds to these sites in the ZIF-67-1@EG/PMS system.

Effective Adsorption of Chlorinated Polyfluoroalkyl Ether Sulfonates from Wastewater by Nano-Activated Carbon: Performance and Mechanisms

Chlorinated polyfluoroalkyl ether sulfonates (F-53B) were often used as mist suppressants in the chrome plating industry, resulting in the large discharge of F-53B-containing electroplating wastewater into the aquatic environment. Due to the high toxicity of F-53B, increasing attention has been paid to its efficient removal from wastewater. In this study, three nano-activated carbons were successfully prepared from coconut shell carbons by a simple one-step KOH activation method. The nitrogen adsorption/desorption experiments showed that the synthesized coconut shell activated carbons possessed a well-developed nano-pore structure, which was favorable for the adsorption of F-53B. The results suggested that the adsorption of F-53B on the coconut shell activated carbons followed pseudo-second-order kinetics and was better fitted in the Langmuir isotherm, indicating that the adsorption of F-53B was mainly controlled by chemical adsorption and was mainly monolayer adsorption. Theoretical calculation results revealed that the faster adsorption rate of F-53B on CSAC_800 than on CSAC_600 and CSAC_700 could be contributed to the lower adsorption energy of F-53B on CSAC_800 and the higher self-diffusion coefficients of F-53B in CSAC_800. The higher adsorption capacity of CSAC_800 (qm = 537.6 mg·g−1) for F-53B than that of CSAC_600 (qm = 396.83 mg·g−1) and CSAC_700 (qm = 476.19 mg·g−1) could be attributed to the higher specific surface area and larger number of adsorption sites of CSAC_800. The results of this study demonstrate that coconut shell activated carbons with a well-developed nano-pore structure are an effective adsorbent for F-53B removal and have a good application prospect.

Tailoring TiO2 finite nanotubes: Doping-induced modulation of electronic, optical, and hydrogen storage properties

In this study, we employ density functional theory calculations to investigate the properties of finite single walled TiO2 finite nanotubes (TiO2NTs). The constructed nanotubes demonstrate geometric stability, as evidenced by positive binding energy and real positive vibrational frequencies obtained from the infrared spectra. Substitutional doping with various atoms (B, N, C, Si, Li, Sc, Fe, and Cu) introduces intriguing effects on the electronic and optical properties of TiO2NTs. Doping with Fe slightly reduces the wide energy gap (∼5 eV) of unmodified TiO2NTs to 4.2 eV, while Si doping significantly decreases the energy gap by half. Furthermore, we investigate the impact of doping TiO2NTs with boron, carbon, nitrogen, iron, cesium, and silicon on their UV–Vis absorption spectra. The introduction of these dopants induces significant redshifts in the absorption peaks, indicating alterations in the electronic energy gap and transitions between specific states. These findings provide valuable insights into the structural and electronic modifications of TiO2NTs. Moreover, we explore the adsorption properties of TiO2NTs for H2 molecules. While unmodified TiO2NTs exhibit low adsorption energy, doping with a small number of C or Si atoms leads to a substantial enhancement in the adsorption energy. Specifically, Si doping achieves adsorption energy of approximately 0.2 eV, accompanied by a hydrogen storage capacity of 6.1 wt%, exceeding the standard capacity of 6.0 wt%. Importantly, the desorption temperature remains comparable to room temperature, ensuring long-term recyclability. These results highlight the potential of doped single-walled TiO2 nanotubes as efficient hydrogen storage devices.

Boron-modified CuO as catalyst for electroreduction of CO2 towards C2+ products

The development for electroreduction of carbon dioxide (CO2) is crucial for achieving sustainable cycles and carbon neutrality. Electroreduction of CO2 to C2+ products can not only mitigate environmental issues by reducing CO2 but also provide high-value chemicals for modern industry. In this study, we synthesized CuO nanosheets (CuO NS) via simple hydrothermal method and modified its electron structure by in-situ boron (B) doping to produce B-CuO NS catalyst. The XPS spectra revealed the successfully doping of B into CuO NS, which obviously changes the electron density of Cu on the surface of CuO NS. As a result, B-CuO NS displayed a higher performance for electroreduction of CO2 compared with original CuO NS. The optimized B-CuO NS catalyst exhibits a faradaic efficiency of 54.78 % for C2+ production at −1.2 V vs. reversible hydrogen electrode (RHE). Based on the structural characterization and Density Functional Theory (DFT) calculations, the introduction of B increases the charge density of Cu, which could process free electrons to adsorb *CO. Thanks to the easier adsorbing of *CO on B-CuO NS as well as the lower adsorption energy of *CO on Cu, C–C coupling reaction was promoted to produce more C2+ products. This work shows a rational design strategy for developing efficient catalysts for electroreduction of CO2.

Visible light-driven C/O-g-C3N4 activating peroxydisulfate to effectively inactivate antibiotic resistant bacteria and inhibit the transformation of antibiotic resistance genes: Insights on the mechanism

Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) dissemination within water pose a serious threat to public health. Herein, C and O dual-doped g-C3N4 (C/O-g-C3N4) photocatalyst, fabricated via calcination treatment, was utilized to activate peroxydisulfate (PDS) to investigate the disinfection effect on tetracycline-resistant Escherichia coli and the transformation frequency of ARGs. As a result, approximately 7.08 log E. coli were inactivated, and 72.36 % and 53.96 % of antibiotics resistance gene (tetB) and 16 S rRNA were degraded respectively within 80 min. Futhermore, the transformation frequency was reduced to 0.8. Characterization and theoretical results indicated that C and O doping in g-C3N4 might lead to the electronic structure modulation and band gap energy reduction, resulting in the production of more free radicals. The mechanism analysis revealed that C/O-g-C3N4 exhibited a lower adsorption energy and reaction energy barrier for PDS compared to g-C3N4. This was beneficial for the homolysis of O-O bonds, forming SO4•− radicals. The attack of the generated active species led to oxidative stress in cells, resulting in damage to the electron transport chain and inhibition of ATP production. Our findings disclose a valuable insight for inactivating ARB, and provide a prospective strategy for ARGs dissemination in water contamination.

Polyaniline/Polydopamine-Regulated Nitrogen-Doped Graphene Aerogel with Well-developed Mesoporous Structure for Supercapacitor Electrode

Graphene-based materials have been widely studied in the field of supercapacitors. However, their electrochemical properties and applications are still restricted by the susceptibility of graphene-based materials to curling and agglomeration during production. In this study, a nitrogen-doped graphene aerogel (NGA) based on the regulation of polydopamine (PDA) and polyaniline (PANI) is proposed for the development of supercapacitors using industrial grade graphene oxide (GO, 2.67 m2/g) as raw material. Due to the rigidity of the PANI, agglomeration is prevented during the reduction of GO sheets. Meanwhile, the flexibility and adhesion of the PDA ensure a stable interaction between the graphene sheets and the PANI. NGAs feature a well-developed mesoporous structure and a high content of nitrogen, which enables the rapid transfer of ions inside them. As revealed by density functional theory (DFT) calculations, NGA heterojunction is characterized by high electronic conductivity, fast electron transfer, and low adsorption energy. For this reason, the supercapacitor obtained with NGA as an electrode produces an excellent capacitive performance, achieving a high area capacitance (123.6 mF·cm−2 at 0.5 mA·cm−2) and a superior long-cycle compression performance (80.7%, 5000 cycles). This study provides an effective solution for the development of supercapacitor electrodes using low-cost GO as raw materials.

Comprehensive protection of Zn metal anode via caprolactam towards highly stable aqueous zinc ions batteries

Rampant side reactions such as hydrogen evolution reaction (HER), corrosion and uncontrollable dendrite growth at anodes greatly impede the application of AZIBs. Herein, caprolactam (CPL) is employed as a crucial electrolyte medium to achieve the aim of highly reversible zinc anodes. CPL molecules exhibit a lower adsorption energy (−1.94 eV) than H2O and preferential binding with Zn anodes, resulting in a H2O-poor anode/electrolyte interface and an enhanced steric effect at the anode surface. This effect effectively hinders the contact between zinc metal and water molecules, consequently facilitating the uniform and controlled deposition of Zn2+. Furthermore, the combination between CPL and Zn2+ contributes to the optimization of solvation structures. Consequently, Zn/Zn batteries with CPL additives realized more than 2100 h stable cycling life under 1 mA cm−2 and 1 mAh cm−2. Moreover, Zn/Cu batteries with CPL additives achieved a reversible plating/stripping process for over 3000 cycles with high average CE of 99.4%. Besides, the assembled Zn/NH4V4O10 full batteries using electrolyte of ZnSO4/CPL also exhibited excellent cyclic performance. The batteries yielded 77.1 mAh g−1 under the current density of 5 A g−1 after 1000 cycles. CPL demonstrates significant potential as a cost-effective and multifunctional electrolyte additive for achieving stable and reliable AZIBs.

Enhanced tetracycline degradation by a confinement structure rGO/Fe1/C3N4 photocathode during the sequential oxygen reduction process

Photoelectrocatalytic (PEC) process based on hydroxyl radicals (•OH) can effectively remove refractory pollutants, however, reducing molecular oxygen to •OH by a PEC process remains a challenge. In this work, an atomically dispersed Fe catalyst (rGO/Fe1/C3N4) was proposed. The rGO/Fe1/C3N4 photocathode showed high efficiency (88.3%, 60 min) and low energy consumption (0.072 kWh/g) in removing tetracycline (TC), and •OH was the main active species for TC degradation. The results of experimental and theoretical calculations revealed that the efficient TC degradation is due to the coupling effect of rGO and Fe atoms. The rGO enhances light absorption and effective electron transfer, thus facilitating the reduction of O2 to H2O2. Subsequently benefiting from the low H2O2 adsorption energy on Fe single atoms, enhanced electron and mass transfer between Fe single atoms and the coordination environment, H2O2 is further reduced to •OH in the confinement structure. Stability test and toxicity analysis in TC degradation demonstrate that the PEC process is an environmentally friendly technology that is stable in the long term. This work provides a new idea for designing photoelectrocatalysts with excellent •OH generation and TC degradation capacity.