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Herein, a unique mesoporous heterostructure (average pore size: 15 nm) cobalt disulfide/carbon nanofibers (CoS 2 /PCNFs) composite with excellent hydrophilicity (contact angle: 23.5°) is prepared using polyethylene glycol (PEG) as a pore-forming agent. The CoS 2 /PCNF electrode exhibits excellent cycle stability (95.2% of initial specific capacitance at 10 A·g −1 after 8000 cycles), good rate performance (46.5% at 10 A·g −1 ), and high specific capacity (86.1 mAh·g −1 at 1 A·g −1 , about 688.8 F·g −1 at 1 A·g −1 ). Density functional theory (DFT) simulation elucidates that CoS 2 tends to transfer substantial charges to CNF. As the center of positive charge, CoS 2 is more likely to capture negative ions in the electrolyte, thus accelerating the ion diffusion process. The excellent properties of the electrode material can not only accelerate the electrochemical reaction kinetics, but also provide abundant redox-active sites and a high Faradaic capacity for the entire electrode due to the synergistic contributions of CoS 2 nanoparticles, mesoporous heterostructure of PCNF, and admirable hydrophilicity of the composite material. A CoS 2 /PCNF-0.25//AC (AC: activated carbon) asymmetric supercapacitor is assembled using CoS 2 /PCNF-0.25 as the positive electrode and AC as the negative electrode, which possesses a high energy density (35.5 Wh·kg −1 at a power density of 824 W·kg −1 ) and superior cycling stability (maintaining over 98% of initial capacitance after 2000 cycles). In addition, the unique CoS 2 /PCNF electrode is expected to be widely used in other electrochemical energy storage devices, such as lithium-ion batteries, sodium-ion batteries, lithium-sulfur batteries, etc.

The accurate and expeditious detection of minute biomolecules within human body fluids holds paramount significance in the advancement of novel electrode materials. In this research, a novel non-enzyme electrochemical sensor was constructed. It was founded on Au@Ni-MOF (Ni(CH 3 CO 2 ) 2 ) hybrids, with Ni(II) (nickel acetate) serving as the precursor. Specifically, [Ni 3 (BTC) 2 ] n (H 3 BTC = 1,3,5-trimesic acid) featuring coordinatively unsaturated Ni(II) sites and decorated with gold nanoparticles was synthesized via an in-situ growth methodology. The Au@Ni-MOF hybrids exhibit outstanding electrochemical and electrocatalytic characteristics, attributable to the meticulous assembly of AuNPs and Ni-MOF. The Au@Ni-MOF (Ni(CH 3 CO 2 ) 2 )/SPCE was fabricated onto the surface of the screen-printed electrode (SPCE). Subsequently, its electrochemical performance was probed for the discrete and concurrent quantification of dopamine (DA) and uric acid (UA) in 0.01 M phosphate-buffered saline through differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Notably, the cathodic peak current manifested a linear correlation with the DA and UA concentrations across an extensive range, spanning from 0.1 µM to 2 mM for DA and from 0.5 µM to 1.5 mM for UA, respectively. This sensor is applicable in non-enzyme sensing of DA and UA. Additionally, the adsorption energy and bond length of the 2D structures of Ni-MOF and Au@Ni-MOF (Ni(CH 3 CO 2 ) 2 ) were ascertained via DFT simulations, thereby affording valuable insights into the interaction mechanisms between biomolecules and the surfaces of these 2D structures.

The rapid increase in antibiotic contaminants such as Tetracycline (TC) in aquatic environments poses significant threats to human health and ecosystems. This study presents a novel Mn-Al layered double hydroxide (LDH) composite with rice husk biochar (RHBC) as a highly efficient visible light photocatalyst for the degradation of TC in wastewater. The Mn-Al-LDH/RHBC composite was synthesized via a simple co-precipitation method and characterized by UV–vis DRS, PL, TRPL, EIS, and TPR tests, confirming its wide visible spectral absorption, low electron–hole recombination rate, and high charge transfer efficiency. Photocatalytic performance tests showed that Mn-Al-LDH/RHBC achieved a 90.10% TC degradation efficiency within 90 min of irradiation. Mechanistic studies using EPR and DFT analysis identified ·OH and ·O₂⁻ as the primary reactive species in TC degradation. Additionally, QSAR analysis demonstrated a reduction in the biotoxicity of TC and its intermediates post-degradation. This work offers a new insight for the utilization of biomass waste and the improvement of Mn-Al-LDH/RHBC photocatalytic performance, and extends the broad potential application of biochar-based photocatalyst in antibiotic-contaminated wastewater treatment applications.

Surface-enhanced Raman spectroscopy (SERS) is an ultra-sensitive and rapid technique that is able to significantly enhance the Raman signals of analytes absorbed on functional substrates by orders of magnitude. Recently, semiconductor-based SERS substrates have shown rapid progress due to their great cost-effectiveness, stability and biocompatibility. In this work, three types of faceted Co3O4 microcrystals with dominantly exposed 100 facets, 111 facets and co-exposed 100-111 facets (denoted as C-100, C-111 and C-both, respectively) are utilized as SERS substrates to detect the rhodamine 6G (R6G) molecule and nucleic acids (adenine and cytosine). C-100 exhibited the highest SERS sensitivity among these samples, and the lowest detection limits (LODs) to R6G and adenine can reach 10−7 M. First-principles density functional theory (DFT) simulations further unveiled a stronger photoinduced charge transfer (PICT) in C-100 than in C-111. This work provides new insights into the facet-dependent SERS for semiconductor materials.

Solid-state batteries offer significant advantages but present several challenges. Given the complexity of these systems, it is good practice to begin the study with simpler models and progressively advance to more complex configurations, all while maintaining an understanding of the physical principles governing solid-state battery operation. The results presented in this work pertain to cells without traditional electrodes, thus providing a foundation for guiding the development of fully functional solid-state cells. The open circuit voltage (OCV) of the Cu/Na2.99Ba0.005ClO composite in a cellulose/Zn pouch cell achieves 1.10 V, reflecting the difference in the chemical potentials of the current collectors (CCs), Zn and Cu, serving as electrodes. After 120 days, while set to discharge, conversely to what was expected, a higher potential difference of 1.13 V was attained (capacity of 5.9 mAh·g−1electrolyte). By incorporating a layer of carbon felt, the OCV became 0.85 V; however, after 95 days, the potential difference increased to 1.20 V. Ab initio simulations were additionally performed on a Cu/Na3ClO/Zn heterojunction showing the formation of dipoles and the Na deposition on Zn which is demonstrated experimentally. The sodium plating on the negative CC (Zn) takes place as the cell is set to discharge at room temperature but is not observed at 40 °C.

Sugarcane bagasse (SCB) was transformed into polyaminocarboxylated modified hydrochar (ACHC) by hydrothermal carbonization (HTC), which was then followed by activation, etherification, amination, and carboxylation successively. ACHC was systematically characterized, and batch adsorption studies were used to assess its methylene blue (MB) adsorption capacity. Adsorption was analyzed by adsorption isotherm models, the adsorption mass transfer model, and the adsorption thermodynamics model. Density functional theory (DFT) was utilized to explain adsorption mechanisms. The findings demonstrated the adsorption was one type of endothermic, spontaneous, and homogenous monolayer adsorption with intra-particle diffusion, containing both chemical and physical adsorption, involving electrostatic attraction, hydrogen bonding, and π-π interaction. At 303 and 323 K, the highest adsorption capacity was 1017.29 and 1060.45 mg·g−1, respectively. Furthermore, when the recycle time was 4, the equilibrium adsorption capacity remained at 665.43 mg·g−1, which implied fairly good regeneration performance. The modification provided a simple, environmentally friendly, and economical solution for converting sugarcane bagasse into an efficient adsorbent for MB treatment.

S-shaped dinaphtho[2,1-b:2′,1′-f]thieno[3,2-b]thiophene (S-DNTT) molecules have shown promise for applications in organic electronic devices, though their molecular characteristics are not fully understood yet. In this study, we first revealed the material characteristics of S-DNTT-10 by vibrational dynamics using Raman spectroscopy and density functional theory (DFT) simulations, employing the B3LYP functional method and the 6-311G (d, p) basis set. The molecular vibrations identified included C–H bending in alkyl chains and the deformation of S-shaped thiophene rings. In addition, surface-enhanced Raman scattering (SERS) with 785 nm incident light was applied to thermally deposited 25 nm S-DNTT-10 thin films with gold (Au) nanostructures. It showed enhanced Raman signals from the lower S-DNTT-10 layers. The findings significantly contribute to the knowledge of S-DNTT-10 molecular properties and also contribute insights into using this material into organic electronic devices in the future.

Human serum albumin (HSA) efficiently transports drugs in vivo: most are organic. Therefore, it is important to delineate the binding of small molecules to HSA. Here, for the first time, we show that HSA binding depends not only on the identity of the d[sup.8] metal ion, Ni[sup.II] or Pd[sup.II], of their complexes with bis(pyrrole-imine), H[sub.2]PrPyrr, but on the pH level as well. Fluorescence quenching data for native and probe-bound HSA showed that sites close to Trp-214 (subdomain IIA) are targeted. The affinity constants, Ka, ranged from ~3.5 × 10[sup.3] M[sup.−1] to ~1 × 10[sup.6] M[sup.−1] at 37 °C, following the order Pd(PrPyrr) > Ni(PrPyrr) at pH levels of 4 and 7; but Ni(PrPyrr) > Pd(PrPyrr) at a pH level of 9. Ligand uptake is enthalpically driven, dependent mainly on London dispersion forces. The induced CD spectra for the protein-bound ligands could be simulated by hybrid QM:MM TD-DFT methods, allowing us to delineate the binding site of the ligands and to prove that the metal chelates neither decompose nor demetallate after uptake by HSA. The transport and delivery of the metal chelates by HSA in vivo is therefore feasible.

In this work, first-principles methods were performed to simulate interactions between hydrogen and common alloying elements of high strength low alloy (HSLA) steel. The world has been convinced that hydrogen could be one of the future clean energy sources. HSLA steel with a balance of strength, toughness, and hydrogen embrittlement susceptibility is expected for application in large-scale hydrogen storage and transportation. To evaluate the property deterioration under a hydrogen atmosphere, hydrogen embrittlement (HE) of HSLA steel attracts attention. However, due to the small size of hydrogen atoms, the mechanism of HE is challenging to observe directly by current experimental methods. To understand the HE mechanism at an atomic level, DFT methods were applied to simulate the effects of alloying elements doping in bcc-Fe bulk structure and grain boundary structure. Furthermore, the potential application of DFT to provide theoretical advice for HSLA steel design is discussed.

Human serum albumin (HSA) efficiently transports drugs in vivo: most are organic. Therefore, it is important to delineate the binding of small molecules to HSA. Here, for the first time, we show that HSA binding depends not only on the identity of the d8 metal ion, NiII or PdII, of their complexes with bis(pyrrole-imine), H2PrPyrr, but on the pH level as well. Fluorescence quenching data for native and probe-bound HSA showed that sites close to Trp-214 (subdomain IIA) are targeted. The affinity constants, Ka, ranged from ~3.5 × 103 M−1 to ~1 × 106 M−1 at 37 °C, following the order Pd(PrPyrr) > Ni(PrPyrr) at pH levels of 4 and 7; but Ni(PrPyrr) > Pd(PrPyrr) at a pH level of 9. Ligand uptake is enthalpically driven, dependent mainly on London dispersion forces. The induced CD spectra for the protein-bound ligands could be simulated by hybrid QM:MM TD-DFT methods, allowing us to delineate the binding site of the ligands and to prove that the metal chelates neither decompose nor demetallate after uptake by HSA. The transport and delivery of the metal chelates by HSA in vivo is therefore feasible.