Reduction Of Gap Research Articles

Next-Generation BiOCl/MXene Nanocomposites: Optimized for Dye Removal and Supercapacitor Applications.

The study focuses on the development of an efficient and sustainable solution for synthetic dye degradation through the hydrothermal synthesis of BiOCl and BiOCl/MXene heterostructures. Structural and compositional properties were analyzed by using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy (XPS) techniques. A significant reduction in the band gap of BiOCl/MXene to 2.97 eV from 3.62 eV for BiOCl was observed via UV spectroscopy, leading to enhanced photocatalysis with 89% degradation efficiency in just 12 min. The mechanism involved and reactive species were confirmed by LC-HRMS and radical trapping tests, while ICP-MS verified metal content in water before and after degradation. Additionally, the nanocomposite demonstrated a specific capacitance of 431.24 F g-1 at a current density of 1 mA cm-2, with an excellent capacitance retention of 94.35% after 2000 cycles. This study highlights BiOCl/MXene as a promising material for both photodegradation and supercapacitor applications.

Computational Design of 3D Lantern Organic Framework.

This study employed a computational approach, particularly Density Functional Theory at B3LYP-D3/6-31+G(d) level to design two new classes of three-dimensional (3D) Lantern Organic Frameworks (LOFs) materials based on trisilasumanene and porphyrin core building units. Particularly, we detail strategies for transitioning from 1D-LOF nanowires to extended 3D structures: first by connecting planar-molecule base units of trisilasumanene or porphyrin using benzene-based linkers, and then connecting silicon anchoring atoms on the bases with other bases that are vertically stacked by sp3-hydrocarbon chains. The 3D-LOF structures are designed to have different pore sizes through the use of various bases, bridges, and linkers. Comparisons of electronic properties of these 3D structures lead to one designing rule. That is, the gap between highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the 3D materials depends only on its base and is nearly independent of the stack size or the length of the sp3-hydrocarbon bridges. Additionally, connecting base units with linkers also extends π-electron conjugation system leading to a reduction in HOMO-LUMO gap. For instance, linking two trisilasumanene molecules significantly narrows HOMO-LUMO gap by 1.75 eV while stacking these bases vertically and connecting them by linear pentane-based bridges yield insignificant change to the gap.

Development and Performance of a PANI@NiMnO3 Nanocomposite for Enhanced Supercapacitors and Photocatalytic Applications.

Conductive polymers are gaining considerable attention as a potential material for supercapacitor electrodes due to their favorable properties. Among these, polyaniline (PANI) stands out as a cost-effective and easy to synthesize, making it a promising candidate for improving energy storage applications. This study presents the synthesis of a hybrid composite consisting of PANI and NiMnO3 (NMO) perovskite using the chemical oxidative polymerization method. The morphology and structure of the composite were analyzed by using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. XRD results showed that the addition of NMO transformed the amorphous structure of PANI into a semicrystalline form, leading to enhanced conductivity. SEM images revealed a more uniform and compact structure, with NMO distributed unevenly within the polymer matrix. Optical analysis indicated that a reduction in the band gap of PANI@NMO reached 2.5 eV. N2 adsorption-desorption measurements confirmed an increase in the surface area and pore volume. The photocatalytic activity of the PANI@NMO nanocomposite was tested by degrading methylene blue (MB) dye under UV/visible light. The nanocomposite showed high efficiency, degrading 87.75% of MB dye after 125 min of irradiation as compared to their counter parts. Additionally, electrochemical tests demonstrated an improved electrochemical performance of the composite due to enhanced crystallinity, increased surface area, and reduced electron-hole recombination rate. These results suggest that the PANI@NMO nanocomposite has great potential for use in supercapacitors and photocatalysis.

Multi-Color Spaceplates in the Visible.

The ultimate miniaturization of any optical system relies on the reduction or removal of free-space gaps between optical elements. Recently, nonlocal flat optic components named "spaceplates" were introduced to effectively compress space for light propagation. However, space compression over the visible spectrum remains beyond the reach of current spaceplate designs due to their inherently limited operating bandwidth and functional inefficiencies in the visible range. Here, we introduce "multi-color" spaceplates performing achromatic space compression at three distinct color channels across the visible spectrum to markedly miniaturize color imaging systems. In this approach, we first design monochromatic spaceplates with high compression factors and high transmission amplitudes at visible wavelengths based on a scalable structure and dielectric materials widely used in the fabrication of meta-optical components. We then show that the dispersion-engineered combination of monochromatic spaceplates with suitably designed transmission responses forms multicolor spaceplates that function achromatically. The proposed multicolor spaceplates, composed of amorphous titanium dioxide and silicon dioxide layers, efficiently replace free-space volumes with compression ratios as high as 4.6, beyond what would be achievable by a continuously broadband spaceplate made of the same materials. Our strategy for designing monochromatic and multicolor spaceplates, along with the presented theoretical and computational results, show that strong space-compression effects can be achieved in the visible range. Our findings may ultimately enable a new generation of ultrathin optical devices for various applications.

The impact of digitization in manufacturing on female employment and gender wage gap

This paper comprehensively examines the impact of digitization in manufacturing on female employment and the gender wage gap, utilizing data from Chinese manufacturing enterprises. The findings indicate that digitization creates more employment opportunities for female workers, increases their employment share, and narrows the gender wage gap. Notably, the increase in female employment due to digitization is more pronounced in private enterprises, as well as in the eastern and central regions, particularly within low-tech industries. Similarly, the effect of digitization on reducing the gender wage gap is most significant in private enterprises, eastern regions, and low-tech sectors. The mechanism underlying these changes suggests that manufacturing digitization enhances female employment through increased output and productivity, thereby contributing to a reduction in the gender wage gap. This study holds significant value for advancing digitization and promoting gender equality in the labor market.

Group VIII Transition Metal (Fe, Ru & Os) Embedded Graphitic Carbon Nitride as an Acetone Sensor: A First Principle Investigation

This study investigates the acetone sensing behavior of pristine graphitic carbon nitride (gCN) and group VIII transition metal (Fe, Ru & Os) embedded gCN monolayer using DFT calculations. Key structural and electronic properties such as adsorption energy, band structure, and density of states (DOS) have been examined. The calculated adsorption energy of pristine gCN is −1.32 eV, which improves to –3.52, −2.75, and −1.73 eV for Fe, Ru, and Os embedded gCN, respectively. The band structure also indicates a reduction in the band gap of gCN after acetone adsorption due to the introduction of Fe, Ru, and Os. Furthermore, after the adsorption of acetone, the DOS values exhibit a significant increase from 13.48 eV−1 for pristine gCN to 439, 423, and 332 eV−1 for Fe, Ru, and Os embedded gCN, respectively.

Synthesis and characterization of zinc-doped hematite nanoparticles for photocatalytic applications and their electronic structure studies by density functional theory

Hematite nanoparticles doped with 1, 3 and 5 % Zn (all % are in molar) were prepared using mechanical alloying. Morphological and phase structure studies using scanning electron microscopy and X-ray diffraction showed nanoparticles possessing a semi-spherical shape and particle size of <50 nm crystallized in rhombohedral structure. The lattice parameters of hematite increased upon Zn doping. The energy-dispersive X-ray and Fourier-transform infrared results demonstrated that Zn was successfully incorporated. The optical behavior of nanoparticles was examined by UV–Vis diffuse reflectance spectroscopy and revealed that Zn doping increased the absorption intensity in the visible light region and decreased the band gap from 1.95 (hematite) to 1.83 eV (3 % Zn). Methylene blue dye degradation by the 3 % Zn sample proved doubling of the photocatalytic activity due to electronic structure modification upon Zn doping. First principles studies using density functional theory performed to investigate the effect of Zn on the electronic band structure of hematite showed that Zn doping caused band gap reduction, causing formation of new energy states, mainly above the valence band. Eventually, the enhancement of Urbach energy and reduction of effective mass, respectively accountable for increasing the relaxation time and mobility of charge carriers, were considered the two main mechanisms regarding the increased photocatalytic behavior of hematite by Zn doping.

Computational study of transition metal coordinated polyaniline: A first principle investigation into tuning the electronic properties of the resulting hybrid material

Tuning the electronic properties of polyaniline remains one of the most important features for the development of advanced materials in electronics. In this contribution, we use density functional theory to investigate the electronic properties of polyaniline when coordinating transition metals (Mn, Fe, Co, Cu, Zn) are embedded in the polymer structure.Importantly, the results reveal that in the presence of transition metal with high electronegativity, the coordinated polyaniline winds up with a decreased gap. Indeed, the band gap for H-PANI decreases from 0.911 eV to 0.513 eV for H-PANI-Mn (lower electronegativity) and to 0.201 eV for H-PANI-Zn (higher electronegativity). This reduction in the energy gap is attributed to enhanced electron delocalization due to increased overlap of electron wavefunctions in the hybrid structure. The results also reveal that the presence of transition metals lead to lower the chemical hardness from 3.252 eV in the case of H-PANI into 0.256 eV for H-PANI-Mn and 0.100 eV for H-PANI-Zn. Additionally, the results from molecular electrostatic potential highlight that PANI-Transition metal sustains more delocalization of charge density distribution compared to H-PANI, leading to molecule polarization which does play a crucial role in various chemical phenomena. These later reveal that the electron density polarization in polyaniline can interestingly be controlled through doping and coordinating the polymer structure with additional transition metals. Therefore, the obtained results might be used in the optimization of electrochemical charge storage in supercapacitors.

Structural and optical properties of Ce-stabilized tetragonal phase and intense blue emission of monoclinic phase in ZrO2 nanoparticles

Structural and optical properties of Ce-stabilized tetragonal zirconium dioxide (ZrO2) and intense blue emission of monoclinic ZrO2 are presented in this paper. Nanoparticles of ZrO2 in the stabilized tetragonal and monoclinic phases have been prepared by the solution combustion method. X-ray diffraction studies and Rietveld refinement of the diffraction pattern show the stabilization of ZrO2 in the tetragonal phase (t-ZrO2) with Ce doping. It is the host-dopant ionic size mismatch that leads to lattice distortion and hence the t-ZrO2 stabilized phase. Raman modes confirm the phase transformation from the monoclinic to a tetragonal phase of ZrO2. The presence of oxygen vacancies and surface states in the samples play a role in altering the optical band gap. The dopant Ce-ions create defects/oxygen vacancies, which act as the trapping sites for electrons and holes/the donor and vacancy-related impurity levels. It is transition between these levels or between delocalized conduction bands that lead to band gap reduction. Photoluminescence studies reveal the presence of structural phase transformation dependent emission bands. The monoclinic phase (m-ZrO2) exhibits an intense blue emission originating from the asymmetric and unusual oxygen coordination of Zr in the m-ZrO2. The chromaticity coordinates indicate that the prepared material and adopted strategies are suitable in the field of optoelectronic application.

Using Er/Cd-Codoped Bi4O5Br2 Microspheres to Enhance Antibiotic Degradation under Visible Illumination: A Combined Experimental and DFT Investigation.

High levels of antibiotic accumulation and the difficulty of degradation can have serious consequences for the environment and, therefore, require urgent attention. To solve this problem, a synergistic Er and Cd ion-codoped Bi4O5Br2 photocatalyst was proposed. The degradation rate of sulfamethoxazole (SMX) by Er/Cd-Bi4O5Br2 was eight times higher than that of pure Bi4O5Br2, exceeding that of single Er-doped or Cd-doped Bi4O5Br2, which was attributed to the ability of Er/Cd-Bi4O5Br2 to generate a variety of free radicals. Experimental results and theoretical calculations suggested a possible mechanism for the improved photocatalytic degradation rate. The reduction of the band gap can facilitate the production of electron-hole pairs, which play a significant role in the production of reactive radicals. Furthermore, an optimal stabilized structure of the ErCd-Bi4O5Br2 dopant system was identified based on the formation energy formulas of different ligand configurations. These findings offer promising potential for the degradation of broad-spectrum antibiotics and provide valuable insights for the design and modification of photocatalytic materials.

Understanding the adsorption performance of hetero-nanocages (C12-B6N6, C12-Al6N6, and B6N6-Al6N6) towards hydroxyurea anticancer drug: a comprehensive study using DFT.

Cancer is a paramount health challenge to global health, which forms tumors that can invade nearby tissues and spread to neighboring cells. Recently, nanotechnology has been used to control the growth of cancer, in which anticancer drugs are delivered to cancerous cells via nanoparticles without damaging healthy tissues. In this study, DFT investigations were carried out to examine the adsorption behavior of C24, B12N12, and Al12N12 nanocages as well as their heterostructures C12-B6N6, C12-Al6N6, and B6N6-Al6N6 towards the hydroxyurea (HU) anticancer drug. In this regard, adsorption energy, interaction distance between the drug and nanocages, charge transfer, energy gap, dipole moment, quantum molecular descriptors, work function, and COSMO surface analysis were analyzed to understand their adsorption performance. Findings demonstrate that the adsorption energies of two hetero-nanocages on their hexagonal (SH) and tetragonal (ST) sites are favorable for the drug delivery process. The computed adsorption energy of B6N6-Al6N6 of the ST/AlN site is 183.59 kJ mol-1, which is higher than that of the C12-Al6N6 nanocage, including minimum adsorption distances. Negative adsorption energy with low adsorption distances implies an attractive interaction between the drug and nanocages. During the interaction, a significant amount of charge is transferred between the drug and nanocages. Furthermore, for both complexes, larger dipole moments were observed in water media compared to gas media. From DOS spectra, prominent peaks were found in the Fermi level after adsorption of HU on the nanocages, implying the reduction of the energy gap. Noticeable overlaps between the PDOS spectra of the nanocages and HU's close contact atom demonstrate the formation of chemical bonds between two specific atoms. Therefore, it can be concluded that among the nanocages, C12-Al6N6 and B6N6-Al6N6 may be suitable carriers for HU drug.

Harnessing the potential of Type-II heterostructures: NiO/TiO2/ZnO fibers for enhanced photocatalytic and electrochemical performance in asymmetric supercapacitors

A novel two-step approach, electrospinning followed by wet chemical route, was used for the synthesis of NiO/TiO2/ZnO heterostructure fibers. Structural, morphological, and elemental analyses confirmed the single-phase formation with a unique, one-dimensional furry insect-like morphology, free of impurities. BET analysis revealed a significant increase in the specific surface area from 12.64 to 54.50 m2/g for NiO/TiO2/ZnO heterostructure fibers, indicating the existence of more active sites for catalytic and redox activities. Optical studies demonstrated a reduction in the band gap of NiO in the presence of TiO2 and ZnO, enhancing the photocatalytic properties. The Langmuir-Hinshelwood kinetic model was employed to measure the reaction rate constant, showing improved photocatalytic performance of NiO by enhancing the separation rate of photo-generated electrons and holes on its surface. Furthermore, the electrochemical performance of the prepared fibers-based asymmetric supercapacitors (ASCs) showed a low polarization, attributed to low charge transfer resistance. The NiO/TiO2/ZnO fibers-based ASCs exhibited higher specific capacitance (108 F/g), with a maximum specific energy density of 9.6 Wh/kg at a specific power density of 2000 W/kg indicating excellent performance suitable for finding potential uses in energy storage applications. Various practical and physical tests further certified the efficient performance of the prepared NiO/TiO2/ZnO heterostructure fibers-based asymmetric supercapacitors. The contribution of NiO and TiO2 to the inner surface were ∼52.02 and ∼47.08 %, respectively. In contrast, the NiO/TiO2/ZnO fibers showed a notable difference, with ZnO-NWs contributing ∼4.99 % to the overall surface. This increase in the inner surface contribution to around 95.01 % indicates that the growth of ZnO-NWs provides additional channels for electrochemical reactions during redox processes and enhances adhesion between the ZnO-NWs and NiO/TiO2 heterostructure, facilitating OH− ions transportation.

Enhanced photocatalytic degradation activity of titanium dioxide by adsorbing aromatic amines through N-bonding

Narrowing the wide band gap of TiO2 (∼3.2 eV) to enhance its visible light efficiency is crucial for advancing photocatalytic degradation of organic pollutants in industrial wastewater. In this study, we achieved band gap reduction and slowed recombination rates by adsorbing some aromatic amines, like aniline and its electron-donating derivatives, onto TiO2. The predominantly present N-bonded amine species reduced the band gap and decelerated charge carriers’ recombination, enhancing photocatalytic degradation under visible light. In contrast, the amine with electron-withdrawing group is adsorbed as only H-bonded species, which showed no improvement in photocatalytic activity, performing similarly to pristine TiO2. This surface modification strategy offers potential for creating visible light-driven photocatalysts for effective degradation of organic pollutants in water.

Financial Openness and Income Inequality in Sub-Saharan Africa: The Role of Development Level and Access to Land

The aim of this study is to analyze the relationship between financial openness and income inequality in Sub-Saharan Africa by controlling the level of development and access to land. By applying the generalized method of moments (GMM) to a sample of 38 countries over the period 2010–2019, the main results are as follows: (i) De facto financial openness reduces income inequality, while de jure financial openness exacerbates income inequality; (ii) Access to land mitigates the effect of de jure openness on income inequalities; (iii) the income level amplifies the effect of reducing financial openness on income inequalities. It follows from these results that access to land can be an excellent instrument for reducing income inequality at the national level due to the reduction of the income gap between rural and urban areas.

Multifaceted insights into Cu(II) complexes with bis(benzimidazole) ligands: Structural investigation, theoretical studies, cytotoxicity evaluation, and antioxidant summarizing

In this study, the synthesized two new ligands, namely bis(1H-benzo[d]imidazole-1-yl) methane [L1] and 1,2-bis(1H-benzo[d]imidazole-1-yl) ethane [L2], from benzimidazole. They chose 1,2-dibromomethane and 1,2-dibromoethane as they are widely used in environmental catalysis and as ligands in conjugated configurations. The researchers were able to synthesize the Cu(II) complexes, [Cu(L1)2]Cl2 or [1] and [Cu(L2)2]Cl2 or [2], at room temperature. They used several analytical techniques, including elemental analysis, magnetic moment measurement, UV–visible spectroscopy, FT-IR spectroscopy, FT-Raman spectroscopy, NMR spectroscopy (including 1H, 13C, DEPT-135, HSQC, and HMBC techniques), ESI-MS analysis, thermogravimetric analysis, and ESR spectroscopy, to characterize the synthesized compounds. They found that the ESR spectra of complexes [1] and [2] suggest that both metal complexes have square planar coordination spheres. In the DFT study of the geometrical optimization of both complexes, the central plane consists of the Cu metal atom connected to four nitrogen atoms. The Cu–N bond lengths are measured at 2.194 Å for [1] and 2.176 Å for [2] whereas the FMO theory's slight reduction in the HOMO-LUMO gap for [2] suggests that it is more reactive and less stable compared to [1]. In addition, the researchers tested the effect of these compounds on human cervical cancer cell lines (HeLa) which showed significant cytotoxic effects under laboratory conditions. Complex [2] had a significant inhibitory impact on the growth of cancer cells. The researchers also assessed the antioxidant effects of the ligands and metal complexes using DPPH, OH, and NO assays and found that [2] had the most potent inhibitory effect on the radicals, with IC50 values of 36.11 μM (DPPH), 28.18 μM (OH), and 26.20 μM (NO).

Research on the Impact of Digital Inclusive Financial Development on the Income Gap between Urban and Rural Residents in Henan Province

This paper begins with an introduction of what digital inclusive finance is; it immediately describes and analyzes the development of digital inclusive finance in Henan, and analyzes the status of disposable incomes of urban and rural residents in Henan from 2011-2021; secondly, based on the digital inclusive finance index released by Peking University from 2011-2021, and based on the panel data of the corresponding years and prefectural cities of Henan Province, it applies the Stata software, through econometric regression and other methods, to empirically analyze the relationship between the development of digital inclusive finance and the income differences between urban and rural residents, to explore the intrinsic relationship between the development of digital inclusive finance and the income differences between urban and rural residents, and to meticulously examine the impact of the coverage, depth of use, and degree of digitalization of digital inclusive finance on the income differences between urban and rural residents. Through the empirical analysis, it is found that the index of digital inclusive finance development has a significant effect on the reduction of the income gap between urban and rural residents, in which the index of the degree of digital inclusive finance digitization has a greater impact on the reduction of the gap between urban and rural residents' incomes.

Early placement of a non-invasive, pressure-regulated, fascial reapproximation device improves reduction of the fascial gap in open abdomens: a retrospective cohort study

BackgroundSince current fascial traction methods involve invasive procedures, they are generally employed late in the management of the open abdomen (OA). This study aimed to evaluate early versus late placement...

The black-white lifetime earnings gap

The average white male born in 1900 earned 2.6 times more labor income over their lifetime than the average Black male. This gap is nearly twice as large as the more commonly studied cross-sectional Black-white earnings gap because 48% of Black males born in 1900 died before the age of 30 as compared to just 26% of white males. We calibrate a model of optimal consumption in a world with mortality risk to data describing the life-cycle earnings and survival probabilities of Black and white males born between 1900 and 1970. We find that convergence in Black and white mortality rates led to a 50% reduction in Black-white welfare gaps between the 1900 and 1920 birth cohorts, even as cross-sectional Black-white income gaps for those cohorts remained relatively constant. However, the Black-white welfare gap stagnated for the 1920 to 1970 birth cohorts as gaps in Black-white life expectancy and income remained stable and large.

Molecular design and characterization of the PANI/yttrium oxide multifunctional nanocomposite material

A detailed density functional theory study was conducted on the nanocomposites formed by polyaniline and yttrium oxide clusters, employing the mixed 6-311G(d,p)/LANL2DZ basis set. The investigation identified the formation of the nanocomposites through strong covalent bonding and moderate electrostatic interactions, resulting in significant binding energies. These interactions contributed to a reduction in the band gap, increased electron activity, and higher chemical reactivity compared to pure polyaniline. The formation of the nanocomposites induced a redshift in the UV-vis absorption spectra, moving the maximum absorption wavelength from the ultraviolet to the visible region, indicating n-type doping. Natural bond orbital analysis confirmed the role of yttrium oxide clusters as electron acceptors, with polyaniline serving as an electron donor.

Studies on Electronic Structure and Optical Properties of MoS2/X (X = WSe2, MoSe2, AlN, and ZnO) Heterojunction by First Principles

The single-layer MoS2 is a highly sought-after semiconductor material in the field of photoelectric performance due to its exceptional electron mobility and narrow bandgap. However, its photocatalytic efficiency is hindered by the rapid recombination rate of internal photogenerated electron–hole pairs. Currently, the construction of heterojunctions has been demonstrated to effectively mitigate the recombination rate of photogenerated electron–hole pairs. Therefore, this paper employs the first principles method to calculate and analyze the four heterojunctions formed by MoS2/WSe2, MoS2/MoSe2, MoS2/AlN, and MoS2/ZnO. The study demonstrates that the four heterojunctions exhibit structural stability. The construction of heterojunctions, as compared to a monolayer MoS2, leads to a reduction in the band gap, thereby lowering the electron transition barrier and enhancing the light absorption capacity of the materials. The four systems exhibit II-type heterojunction. Therefore, the construction of heterojunctions can effectively enhance the optical properties of these systems. By forming heterojunctions MoS2/WSe2 and MoS2/MoSe2, the absorption coefficient in the visible light region is significantly increased, resulting in a greater ability to respond to light compared to that of MoS2/ZnO and MoS2/AlN. Consequently, MoS2-based heterojunctions incorporating chalcogenide components WSe2 and MoSe2, respectively, exhibit superior catalytic activity compared to MoS2 heterojunctions incorporating non-chalcogenide components ZnO and AlN, respectively. The absorption spectrum analysis reveals that MoS2/MoSe2 exhibits the highest light responsivity among all investigated systems, indicating its superior photoelectric performance.