Isomerization of surface functionalized SWCNTs and the critical influence on photoluminescence: static calculations and excited-state dynamics simulations.

Single-walled carbon nanotubes (SWCNTs) functionalized with sparse surface chemical groups are promising for a variety of optical applications such as quantum information and bio-imaging. However, the luminescence efficiencies and stability, two key aspects, undoubtedly govern their practical usage. Herein, we assess the surface migration of oxygen and triazine groups on as-modified SWCNT fragments by adopting transition state theory and explore the de-excitation of oxygen-functionalized SWCNT fragments by performing non-adiabatic excited-state dynamics simulations. According to the predicted moderate or even small reaction barriers, the migration of both oxygen and triazine groups is feasible from an sp3 defect configuration forming an energetically more stable sp2 configuration at moderate or even room temperatures. Such isomerization leads to drastically different light emission capabilities as indicated by the large or zero oscillator strengths. During the dynamics simulations, the lowest excited singlet (S1) state rapidly decays in energy within 20 fs and then fluctuates until the end, providing insights into the emission mechanism of SWCNTs. This study highlights the potential intrinsic limitations of surface-functionalized SWCNTs for luminescence applications.

Co-Doped Ni3V2O8 Nanofibers Achieving d-d Orbital Coupling for Electrocatalytic Oxygen Reduction.

Efficient and robust non-platinum-group metal electrocatalysts for O2 reduction are a prerequisite for practical high-performance fuel cells and metal-air batteries. Herein, we reported an integrated principle of gradient electrospinning and controllable pyrolysis to fabricate various Co-doped Ni3V2O8 nanofibers with high oxygen reduction reaction (ORR) activity. The representative Co1.3Ni1.7V2O8 nanofibers showed outstanding ORR performance in an alkaline solution with a half-wave potential (E1/2) of 0.874 V vs RHE, along with high long-term stability. Furthermore, the introduction of Co could effectively restrain the growth of nanoparticles and change the electronic structure of Ni3V2O8. Control experiments and theoretical calculations demonstrated that upon Co-doping, the hybridization between the 3d orbital for both Co and Ni guaranteed the stable adsorption interaction with O2 over Ni and Co metal centers. Meanwhile, the weakened binding ability of Ni3V2O8 to OH* reduced the ORR free energy. Overall, the synergistic effect of Co and Ni metal cations essentially reflected the origin of ORR activity on the Co-doped Ni3V2O8 nanofibers. This work offers new insights and practical guidance for designing highly active ORR catalysts for electrochemical clean energy conversion and storage.

0D/1D CuWO4/Mn0.3Cd0.7S S-scheme heterojunctions for full-spectrum bifunctional photocatalytic degradation and hydrogen production.

Integrating photocatalytic oxidation for pollutant removal with hydrogen production via photocatalysis presents a promising approach for sustainable water purification and renewable energy generation, circumventing the sluggish multi-electron transfer inherent in photocatalytic water oxidation. This study introduces novel zero-/one-dimensional (0D/1D) CuWO4/Mn0.3Cd0.7S step-scheme (S-scheme) heterojunctions that exhibit exceptional bifunctional capabilities in photocatalytic degradation and hydrogen production under full-spectrum illumination. The degradation efficiency for tetracycline (TC) using 5 %-CuWO4/Mn0.3Cd0.7S reaches 94.3 % and 94.5 % within 60 min and 6 h, respectively, under ultraviolet-visible (UV-Vis) and near-infrared (NIR) light. Notably, these 0D/1D CuWO4/Mn0.3Cd0.7S S-scheme heterojunctions demonstrate superior hydrogen production, achieving rates of 12442.03 µL g-1h-1 and 2418.54 µL g-1h-1 under UV-Vis light and NIR light irradiation, respectively-these rates are 2.3 times and 55.2 times higher than that of Mn0.3Cd0.7S alone. This performance enhancement is attributed to the intrinsic dimensional effects, transitions of transition metal d-d orbitals, and S-scheme hole/electron (h+/e-) separation characteristics. Additionally, experimental results and density functional theory (DFT) calculations have clarified the modulation of electronic configurations, band alignment, and interfacial interactions via 0D/1D S-scheme heterojunction engineering. This study sheds light on the electron transfer mechanism within S-scheme heterojunction and enhances the effectiveness, economy, and sustainability of recalcitrant pollutant removal and hydrogen production.

Bimetallic sulfide/N-doped carbon composite derived from Prussian blue analogues/cellulose nanofibers film toward enhanced oxygen evolution reaction.

Exploiting effective, stable, and cost-efficient electrocatalysts for the water oxidation reaction is highly desirable for renewable energy conversion techniques. Constructional design and compositional manipulation are widely used approaches to efficaciously boost the electrocatalytic performance. Herein, we designed a NiFe-bimetallic sulfide/N-doped carbon composite via a two-step thermal treatment of Prussian blue analogues/cellulose nanofibers (PBA/CNFs) film. The NiFe-bimetallic sulfide/N-doped carbon composite displayed enhanced OER performance in an alkaline environment, with an overpotential of 282 mV at 10 mA cm-2, a Tafel slope of 59.71 mV dec-1, and good stability, making the composite a candidate electrocatalyst for OER-related energy equipment. The introduction of CNFs in the precursor prevented the aggregation of PBA nanoparticles (NPs), exposed more active sites, and the resulting carbon substrate enhanced the electroconductivity of the composite. Moreover, the synergistic effect of Ni and Fe in the bimetallic sulfide could modulate the configuration of electrons, enrich the catalytically active sites, and augment the electric conductivity, thus ameliorating the OER performance. This study broadens the application of MOF-CNF composites to construct hierarchical structures of metal compounds and provides some thoughts for the development of cost-effective precious-metal-free catalysts for electrocatalysis.

Efficient wide-spectrum one-dimensional MWO4 (M = Mn, Co, and Cd) photocatalysts: Synthesis, characterization and density functional theory study.

Broadening the absorption region to near-infrared (NIR) light is critical for the photocatalysis due to the larger proportion and stronger penetration of NIR light in solar energy. In the present paper, one-dimensional (1D) MWO4 (M = Mn, Co, and Cd) materials synthesized by electrospinning technique, were studied by combining the density functional theory (DFT) with experiment results, which possessed the enhanced light absorption capability within the range of 200-2000 nm. It was proved that in the ultraviolet-visible (UV-Vis) region, the absorption bands of CoWO4 and MnWO4 samples were attributed to the metal-to-metal charge transfer mechanism, while the absorption of CdWO4 sample may be referable to the ligand-to-metal charge transfer mechanism. In the near-infrared (NIR) region, the absorption of CoWO4 and MnWO4 primarily originated from the d-d orbital transitions of Mn2+ and Co2+. The photocatalytic experimental results showed that the degradation rates for bisphenol A (BPA) over CoWO4, MnWO4, and CdWO4 photocatalysts under UV-Vis/NIR light irradiation for 140 min/12 h were 78.8 %/75.9 %, 23.8 %/21.3 %, 12.8 %/8.7 %, respectively. This research offers the novel insights into the precise construction of tungstate catalytic systems and contributes to the advancement of UV-Vis-NIR full spectrum photocatalytic technology, and lays a foundation for a cleaner and more environmental-friendly future.

Cerebellar Structural Abnormality in Autism Spectrum Disorder: A Magnetic Resonance Imaging Study.

OBJECTIVE: This study uses structural magnetic resonance imaging to explore changes in the cerebellar lobules in patients with autism spectrum disorder (ASD) and further analyze the correlation between cerebellar structural changes and clinical symptoms of ASD. METHODS: A total of 75 patients with ASD and 97 typically developing (TD) subjects from Autism Brain Imaging Data Exchange dataset were recruited. We adopted an advanced automatic cerebellar lobule segmentation technique called CEREbellum Segmentation to segment each cerebellar hemisphere into 12 lobules. Normalized cortical thickness of each lobule was recorded, and group differences in the cortical measures were evaluated. Correlation analysis was also performed between the normalized cortical thickness and the score of Autism Diagnostic Interview-Revised. RESULTS: Results from analysis of variance showed that the normalized cortical thickness of the ASD group differed significantly from that of the TD group; specifically, the ASD group had lower normalized cortical thickness than the TD group. Post-hoc analysis revealed that the differences were more predominant in the left lobule VI, left lobule Crus I and left lobule X, and in the right lobule VI and right lobule Crus I. Lowered normalized cortical thickness in the left lobule Crus I in the ASD patients correlated positively with the abnormality of development evident at or before 36 months subscore. CONCLUSION: These results suggest abnormal development of cerebellar lobule structures in ASD patients, and such abnormality might significantly influence the pathogenesis of ASD. These findings provide new insights into the neural mechanisms of ASD, which may be clinically relevant to ASD diagnosis.

High-Temperature Liquid-Liquid Phase Transition in Glass-Forming Liquid Pd43Ni20Cu27P10.

Liquid-liquid phase transition (LLPT) is a transition from one liquid state to another with the same composition but distinct structural change, which provides an opportunity to explore the relationships between structural transformation and thermodynamic/kinetic anomalies. Herein the abnormal endothermic LLPT in Pd43Ni20Cu27P10 glass-forming liquid was verified and studied by flash differential scanning calorimetry (FDSC) and ab initio molecular dynamics (AIMD) simulations. The results show that the change of the atomic local structure of the atoms around the Cu-P bond leads to the change in the number of specific clusters <0 2 8 0> and <1 2 5 3>, which leads to the change in the liquid structure. Our findings reveal the structural mechanisms that induce unusual heat-trapping phenomena in liquids and advance the understanding of LLPT.

Hierarchically Porous WO3/CdWO4 Fiber-in-Tube Nanostructures Featuring Readily Accessible Active Sites and Enhanced Photocatalytic Effectiveness for Antibiotic Degradation in Water.

The intentional design and construction of photocatalysts containing heterojunctions with readily accessible active sites will improve their ability to degrade pollutants. Herein, hierarchically porous WO3/CdWO4 fiber-in-tube nanostructures with three accessible surfaces (surface of core fiber and inner and outer surfaces of the porous tube shell) were fabricated by an electrospinning method. This WO3/CdWO4 heterostructure, assembled by interconnected nanoparticles, displays good photocatalytic degradation of ciprofloxacin (CIP, 93.4%) and tetracycline (TC, 81.6%) after 90 min of simulated sunlight irradiation, much higher than the pristine WO3 (<75.3% for CIP and <53.6% for TC) or CdWO4 materials (<58.9% for CIP and <39.5% for TC). The WO3/CdWO4 fiber-in-tube promotes the separation of photoinduced electrons and holes and also provides readily accessible reaction sites for photocatalytic degradation. The dominant active species determined by trapping active species and electron paramagnetic resonance were hydroxyl radicals followed by photogenerated holes and superoxide anions. The WO3/CdWO4 materials formed a Z-scheme heterojunction that generated superoxide anion and hydroxyl radicals, leading to degradation of antibiotics (CIP and TC) via photocatalysis in aqueous solution.

Electrospun Mesoporous InVO4 /TiO2 Nanobelts with Enhanced Photocatalytic Properties.

In the present paper, mesoporous InVO4 /TiO2 nanobelts with diameter about 400 nm have been synthesized by elaborately designed electrospinning process. The microstructures of InVO4 /TiO2 nanobelts are characterized in detail, and their photoelectrocatalytic properties are comprehensively investigated by the photocatalytic degradation tests with tetracycline (TTC) and rhodamine B (RhB) waste water. Furthermore, the energy bandgap and density of states of orthorhombic InVO4 and anatase TiO2 are modeled and analyzed by density functional theory. Compared with single InVO4 nanobelts and TiO2 nanofibers, mesoporous InVO4 /TiO2 nanobelts possess the extraordinary photocatalytic efficiencies and exceptional cycle performances, which may be ascribed to the successful construction of heterostructures between InVO4 and TiO2 and unique one-dimensional belt structures.

Facile Electrospinning of CeO2 /Bi2 WO6 Heterostructured Nanofibers with Excellent Visible-light-driven Photocatalytic Performance.

One-dimensional (1D) CeO2 /Bi2 WO6 heterostructured nanofibers with a diameter of about 300 nm were successfully synthesized by using a straightforward strategy combining an electrospinning technique with a sintering process. The acquired products were characterized by thermogravimetric and differential scanning calorimetric (TG-DSC), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) surface area measurements, and UV/Vis spectroscopy. The obtained CeO2 /Bi2 WO6 heterostructured nanofibers exhibited an excellent photocatalytic property for the degradation of Rhodamine B (RhB) dye driven by visible light due to the promoted separation of photoelectrons and holes and the large contact area between the photocatalyst and organic pollutant.