Search Results (119)

A layered bimetallic CoMo-LDH precursor was prepared on nickel foam via a hydrothermal method, and a 3D hierarchical flower-like nanosheet CoMoP/NF electrocatalyst with a crystalline–amorphous heterostructure was constructed in situ through low-temperature phosphidation. The water electrolysis performance was optimized by adjusting the Co/Mo molar ratio. The 3D hierarchical porous structure provides a large specific surface area and abundant active sites, and Mo doping effectively modulates the electronic structure. The catalyst exhibits superior HER performance with overpotentials of only 37 mV and 65 mV at 10 mA·cm⁻² in acidic and alkaline media and shows a lower HER overpotential than commercial Pt/C at current densities above 426 mA·cm⁻² in acidic conditions. Meanwhile, this catalyst delivers an OER overpotential of 729 mV at 500 mA·cm⁻² in alkaline media and can operate stably for 50 h. The assembled two-electrode overall water splitting cell only requires 1.42 V at 10 mA·cm⁻², outperforming Pt/CǁRuO₂ (1.52 V). This work offers a promising strategy for designing low-cost and high-efficiency overall water splitting electrocatalysts for high-current-density applications. Full article

Developing an ultrasensitive electrochemiluminescence (ECL) detection platform remains challenging due to the limited enrichment efficiency of ECL emitters and co-reactants at the electrode interface, as well as the insufficient catalytic enhancement of co-reactant conversion. Moreover, simultaneous in situ analyte enrichment and efficient anti-interference capability are often difficult to achieve in a single sensing interface. Herein, a new ECL platform was developed based on nanocatalyst-supported nanochannel-confined surfactant micelle (SM) system, which integrates an enhanced luminol-dissolved oxygen (DO) ECL response for the ultrasensitive detection of antibiotic rifampicin (RIF). A nanocomposite comprising nitrogen-doped graphene quantum dots and a molybdenum disulfide nanosheet (NGQDs@MoS₂) was modified on an indium tin oxide (ITO) electrode. This nanocomposite layer catalyzed the oxygen reduction reaction (ORR), boosting the co-reactant efficiency of DO. Vertically ordered mesoporous silica film filled with surfactant micelles (SM@VMSF) was subsequently grown in situ on the NGQDs@MoS₂ surface. The hydrophobic micelles enable the simultaneous enrichment of luminol, DO, and RIF. Integrating the triple-enrichment effect of surfactant micelles with the high electrocatalytic effect of NGQDs@MoS₂ nanocomposite results in significant ECL enhancement of the luminol–DO. SM@VMSF also provides an excellent molecular sieving effect, endowing the sensor with high anti-interference capability and stability. RIF quenches the ECL signal by consuming superoxide anion radicals, enabling sensitive detection. Detection of RIF was established with a high sensitivity (2927 a.u. per nM) wide linear range (10 pM to 10 μM) and a low limit of detection (LOD, 2.5 pM). The fabricated sensor exhibits good selectivity and high fabrication reproducibility (relative standard deviation, RSD, of 1.9%). Additionally, the determination of RIF in eye drops and seawater samples was realized. This work offers new insights for the design of high-performance ECL sensing interfaces and sensitive detection of RIF. Full article

In this work, a comprehensive first-principles investigation of the electronic, magnetic, and optical properties of pristine and Fe-, Co-, and Ni-doped MoS₂ monolayers is presented within the framework of density functional theory. Substitutional transition-metal doping at the Mo site is shown to induce spin-polarized impurity states within the pristine band gap, leading to significant modifications of the electronic structure, including metallic, semimetallic, or half-metallic behavior depending on the dopant species. The calculated spin-resolved band structures and projected density of states reveal a strong hybridization between the dopant $3d$ orbitals and the Mo-$4d$/S-$3p$ states, giving rise to sizable magnetic moments and dopant-dependent exchange splitting. When spin–orbit coupling is included, the combined effect of exchange interactions and relativistic effects leads to an effective valley splitting at the K and $K^{\prime }$ points, whose magnitude and sign depend sensitively on the chemical nature of the dopant. Optical properties are analyzed within a linear-response framework, showing pronounced dopant-induced modifications of the optical spectra. While the pristine monolayer exhibits well-defined excitonic features, transition-metal substitution introduces low-energy optical transitions associated with impurity-related states. Consequently, the exciton binding energies estimated from the difference between the electronic and optical gaps are interpreted as effective measures of dopant-induced perturbations to optical transitions, rather than as quantitative many-body excitonic binding energies in the strict sense. These results provide microscopic insight into the interplay between magnetism, spin–orbit coupling, and optical response in doped MoS₂ monolayers, highlighting the potential of transition-metal substitution as a route to engineer spin- and valley-dependent phenomena in two-dimensional materials. Full article

Interlayer-sliding ferroelectricity in van der Waals bilayers enables ultralow-power switching, but practical devices are often limited by contact/interface scattering and weak coupling between polarization and transport. We propose homophase lateral architectures based on bilayer Janus MoSSe: a 1T/2H/1T ferroelectric tunnel homojunction and an H-phase lateral p–i–n photodetector (artificially doped electrode). Metallic 1T electrodes largely eliminate contact barriers and maximize polarization-driven tunneling modulation. Using non-equilibrium Green’s function–density functional theory (Perdew–Burke–Ernzerhof approximation, without explicit spin–orbit coupling), we find that AB to BA sliding reduces the current from the nA range to the pA range, with the minimum current of|I_OFF|_min = 2.83 pA, yielding giant tunneling electroresistance up to 5.3 × 10⁴%. Projected local density of states reveals a non-rigid long-range potential redistribution that reshapes the tunneling barrier and opens high-transmission channels. In the p–i–n photodetector, the response is strongly anisotropic and stacking-dependent: AB reaches photocurrent density J_ph ≈ 7.2 µA·mm⁻² at 2.6 eV for in-plane light versus ≈ 2.9 µA·mm⁻² at 3.5 eV for out-of-plane, and exceeds BA by 1.5–1.8 times due to density of states advantages and Mo-d orbital selection rules. Bilayer Janus MoSSe therefore provides a reconfigurable platform for high-contrast memory and polarization-sensitive photodetection. Full article

To overcome the physical constraints during the miniaturization of conventional semiconductor devices, spintronics is playing an increasingly prominent role. The Rashba effect, characterized by spin–momentum locking, has emerged as a promising solution to address challenges. Two-dimensional (2D) Janus transition metal dichalcogenides (TMDCs) break spatial inversion symmetry, creating favorable conditions for the Rashba effect. Based on first-principles calculations, 2D Janus materials XMoYZ₂ (X = S/Se/Te; Y = Si/Ge; Z = N/P) were investigated, with strain, external electric field and charge doping employed to modulate the Rashba effect. The strain results reveal that the Rashba constants of XMoYZ₂ increase significantly with compressive strain. Specifically, after applying uniaxial strain, the Rashba constant of TeMoSiP₂ is enhanced to ~2.2 times its initial value. Compressive strain reduces atomic spacing, enhances orbital overlap, and increases spin–orbit coupling (SOC) strength. All the TeMoYZ₂ materials exhibit significant anisotropy under uniaxial strain, which is favorable for spin-oriented transport. SeMoGeP₂ shows an almost linear Rashba constant–electric field correlation, while TeMoGeP₂ and TeMoSiP₂ show non-monotonic variation. The Rashba constant of TeMoSiP₂ can be enhanced to ~2.7 times its intrinsic value under either positive or negative applied electric fields. Charge doping induces negligible changes in the SOC effect. Finally, the optical absorption properties of TeMoGeP₂, TeMoSiN₂, and TeMoSiP₂ were investigated. This study clarifies the mechanism underlying the enhancement of Rashba constants in XMoYZ₂ materials, enriching the research landscape of spintronics. Full article

This study investigates pure and Ag-doped SrMoO₄ powders (Sr_1−xAg_xMoO₄, x = 0, 0.01, 0.07), focusing on structural, optical, and functional properties. We evaluate its photocatalytic performance, capacitance response in lactate solution and water, and antimicrobial activity in textiles. The diffraction patterns could be indexed to the pure tetragonal phase SrMoO₄. The doping of SrMoO₄ with Ag⁺ ions affects the morphology and particle size of the samples designed by co-precipitation. SrMoO₄ pure and Ag⁺-doped samples exhibited promising results in detecting water and lactate solutions, as well as photocatalysis. Pure SrMoO₄ was more efficient in the photodegradation of methylene blue (MB) than the sample doped with Ag⁺. Among the bactericidal test results, sample SMO:0.01-P4, without light, in S. aureus, and SMO:0.07-P3, with light in E. coli, showed a slight distance from the inhibition halo. These results suggest that the treated textile may possess a characteristic bactericidal capacity that deserves further exploration. This comprehensive analysis offers insights into the structure–function relationship of SrMoO₄:Ag and advances the development of multifunctional materials. Full article

We employed density functional theory (DFT) to investigate the effect of tungsten (W) doping on the crystal structure, electronic properties, and optical response of Bi₂MoO_6−xW_xO₆. The results show that W doping retains the Aurivillius orthorhombic lattice structure while inducing localized distortions. All doping systems retain semiconductor characteristics with a band gap ranging from 2.11 to 2.26 eV. The valence band is mainly composed of O-2p orbitals, while the conduction band consists of Mo-4d and W-5d states. As W doping increases, the influence of W-5d states near the conduction band edge intensifies, modulating the electronic structure. Optical calculations show that W doping shifts the absorption edge and allows for precise adjustment of the absorption threshold in the visible light range. These findings provide insight into how W doping affects the electronic and optical properties of γ-Bi₂MoO₆ and offer a theoretical basis for improving Bi₂MoO₆-based photocatalytic materials. Full article

Four different MIL-68(Al) catalysts were synthesized and characterized by XPS, SEM, TEM, XRD, DLS, Nitrogen adsorption removal, and other methods. An aluminum-based MOF (Metal Organic Framework) (MIL-68(Al))/graphite oxide (GO) composite with TiO₂ showed the largest BET specific area with best adsorption performance. Representation demonstrated that MIL-68(Al) and TiO₂ nanoparticles are uniformly dispersed on the surface of the GO lamellar, and a tight heterojunction structure is formed between them. The MIL-68(Al)/GO/TiO₂ exhibits good pore characteristics, structural morphology, and catalytic performance. Adsorption experiments of methyl orange can reach 99.7% with the effect of MIL-68(Al)/GO/TiO₂ in water for 20 min. Moreover, the pH range can be applied to 1–13 and a high concentration of 200 mg/L methyl orange solution also worked well. In addition, this kind of catalyst can also be used for rhodamine B, methylene blue, congo red, and tetracycline in 20 min with good adsorption. Meanwhile, simple filtration can quickly recover MIL-68(Al)/GO/TiO₂ and effectively reuse it. Free radical capture experiments showed a large number of •OH radicals during the adsorption of MO (Methyl Orange) solution by MIL-68(Al)/GO/TiO₂. Meanwhile, the electrostatic interaction, π-π packing and hydrogen bonding make MIL-68(Al)/GO/TiO₂ have a higher adsorption capacity for MO. Therefore, co-doping optimized the structure of MIL-68(Al), enhancing its stability in strong acids and bases while improving adsorption performance across a broader pH range than previously reported. This work addresses the instability of MIL-68(Al) under extreme conditions, demonstrating its significant potential for wastewater treatment applications. Full article

This research introduces a synergistic photoelectrocatalytic (PEC) system designed for the effective degradation of tetracycline (TC), integrating a PO₄³⁻-grafted Mo-doped BiVO₄ (PO₄³⁻-Mo:BiVO₄) photoanode with a Pd-loaded ordered mesoporous carbon (Pd/CMK-3) cathode. The incorporation of Mo doping and PO₄³⁻ modification significantly improved the photoanode’s charge separation efficiency, achieving a photocurrent density of 2.9 mA cm⁻², and fine-tuned its band structure to enhance hydroxyl radical (·OH) generation. Meanwhile, the Pd/CMK-3 cathode promoted a two-electron oxygen reduction reaction pathway, producing hydrogen peroxide (H₂O₂) and facilitating molecular oxygen activation via atomic hydrogen (H*) intermediates. Under optimized conditions—1.0 V vs. Ag/AgCl of anodic potential, pH 6.58, and oxygen saturation—the combined system accomplished 80% TC degradation within 60 min, markedly surpassing the performance of the photoanode (72%) or cathode (71%) alone. Notably, this synergistic approach also reduced energy consumption to 0.0065 kWh m⁻³, outperforming individual components. Radical quenching experiments and liquid chromatography–mass spectrometry (LC-MS) analysis revealed that the photogenerated holes (h⁺) and ·OH were the key reactive species responsible for TC mineralization. The system demonstrated remarkable stability, with only a 2.96% decline in activity, and effectively degraded other contaminants, such as phenol, 4-chlorophenol, and ciprofloxacin. This study highlights an energy-efficient PEC strategy that harnesses the combined strengths of anodic oxidation and cathodic molecular oxygen activation to significantly enhance the removal of organic pollutants. Full article

This study presents the development of Cu-doped NiMo/TiO₂ photoelectrocatalysts for simultaneous green hydrogen production and pharmaceutical pollutant removal under simulated solar irradiation. The catalysts were synthesized via wet impregnation (15 wt.% total metal loading with 0.6 wt.% Cu) and thermally treated at 400 °C and 900 °C to investigate structural transformations and catalytic performance. Comprehensive characterization (XRD, BET, SEM, XPS) revealed phase transitions, enhanced crystallinity, and redistribution of redox states upon Cu incorporation, particularly the formation of NiTiO₃ and an increase in oxygen vacancies. Crystallite sizes for anatase, rutile, and brookite ranged from 21 to 47 nm at NiMoCu400, while NiMoCu900 exhibited only the rutile phase with 55 nm crystallites. BET analysis showed a surface area of 44.4 m²·g⁻¹ for NiMoCu400, and electrochemical measurements confirmed its higher electrochemically active surface area (ECSA, 2.4 cm²), indicating enhanced surface accessibility. In contrast, NiMoCu900 exhibited a much lower BET surface area (1.4 m²·g⁻¹) and ECSA (1.4 cm²), consistent with its inferior photoelectrocatalytic performance. Compared to previously reported binary NiMo/TiO₂ systems, the ternary NiMoCu/TiO₂ catalysts demonstrated significantly improved hydrogen production activity and more efficient photoelectrochemical degradation of paracetamol. Specifically, NiMoCu400 showed an anodic peak current of 0.24 mA·cm⁻² for paracetamol oxidation, representing a 60% increase over NiMo400 and a cathodic current of −0.46 mA·cm⁻² at −0.1 V vs. RHE under illumination, nearly six times higher than the undoped counterpart (–0.08 mA·cm⁻²). Mott–Schottky analysis further revealed that NiMoCu400 retained n-type behavior, while NiMoCu900 exhibited an unusual inversion to p-type, likely due to Cu migration and rutile-phase-induced realignment of donor states. Despite its higher photosensitivity, NiMoCu900 showed negligible photocurrent, confirming that structural preservation and surface redox activity are critical for photoelectrochemical performance. This work provides mechanistic insight into Cu-mediated photoelectrocatalysis and identifies NiMoCu/TiO₂ as a promising bifunctional platform for integrated solar-driven water treatment and sustainable hydrogen production. Full article

This study employs density functional theory (DFT) to investigate the electronic and optical properties of molybdenum (Mo) and chalcogen (S, Se, Te) co-doped anatase TiO₂. Two co-doping configurations were examined: Model 1, where the dopants are adjacent, and Model 2, where the dopants are farther apart. The incorporation of Mo into anatase TiO₂ resulted in a significant bandgap reduction, lowering it from 3.22 eV (pure TiO₂) to range of 2.52–0.68 eV, depending on the specific doping model. The introduction of Mo-4d states below the conduction band led to a shift in the Fermi level from the top of the valence band to the bottom of the conduction band, confirming the n-type doping characteristics of Mo in TiO₂. Chalcogen doping introduced isolated electronic states from Te-5p, S-3p, and Se-4p located above the valence band maximum, further reducing the bandgap. Among the examined configurations, Mo–S co-doping in Model 1 exhibited most optimal structural stability structure with the fewer impurity states, enhancing photocatalytic efficiency by reducing charge recombination. With the exception of Mo–Te co-doping, all co-doped systems demonstrated strong oxidation power under visible light, making Mo-S and Mo-Se co-doped TiO₂ promising candidates for oxidation-driven photocatalysis. However, their limited reduction ability suggests they may be less suitable for water-splitting applications. The study also revealed that dopant positioning significantly influences charge transfer and optoelectronic properties. Model 1 favored localized electron density and weaker magnetization, while Model 2 exhibited delocalized charge density and stronger magnetization. These findings underscore the critical role of dopant arrangement in optimizing TiO₂-based photocatalysts for solar energy applications. Full article

MXenes have emerged as promising candidates for energy storage and catalyst design. Through detailed density functional theory (DFT) calculations, we designed a series of new 2D composite MXene-based nanomaterials by covering excellent TM₃N₂ MXenes (TM = Nb, Ta, Mo, and W) with graphene or buckled silicene. Our findings demonstrate that this coating can lead to high catalytic activity for hydrogen evolution reactions (HER) in these composite MXene-based systems, with silicene exhibiting superior performance compared to graphene. The relevant carbon and silicon atoms in the coated materials serve as active sites for HER due to complex electron transfer processes. Additionally, doping N or P atoms into graphene/silicene, which have similar atomic radii, but larger electronegativity than C/Si atoms, can further enhance the HER activity of adjacent carbon or silicon atoms, thus endowing the composite systems with higher HER catalytic performance. Coupled with their high stability and metallic conductivity, all these composite systems show great potential as electrocatalysts for HER. These remarkable findings offer new strategies and valuable insights for designing non-precious and highly efficient MXene-based HER electrocatalysts. Full article

In this study, Bi₂MoO₆ nanoflowers with different molybdenum sources were in situ grown on the surface of g-C₃N₄ nanosheets (OCN) by a simple one-step solvothermal method. The effects of doping and different molybdenum sources on the photocatalytic degradation and bactericidal activity of Bi₂MoO₆/OCN were discussed. Among them, the solvothermal preparation of P-Bi₂MoO₆/OCN using phosphomolybdic acid as molybdenum source can make up for the shortcomings caused by the destruction of OCN structure by generating more lattice defects to promote charge separation and constructing Lewis acid/base sites to effectively improve the photocatalytic performance. In addition, by adding phosphoric acid to increase the P-doped content, more exposed alkaline active sites are induced on the surface of P-Bi₂MoO₆/OCN, as well as larger specific surface area and charge transfer efficiency, which further improve the photocatalytic performance. Finally, the optimized 16P-Bi₂MoO₆/OCN showed a degradation rate of 99.7% for 20 mg/L rhodamine B (RhB) within 80 min under visible light, and the antibacterial rates against E. coli, S. aureus and P. aeruginosa within 300 min were 99.58%, 98.20% and 97.48%, respectively. This study provides a reference for optimizing the synthesis of environmentally friendly, solar-responsive, photocatalytic sterilization materials from the perspective of preparation, raw materials and structure. Full article

Two-dimensional (2D) n-MoS₂ nanosheets (NSs) synthesized via the sol–gel method were deposited onto p-type heavily boron-doped diamond (BDD) film to form a n-MoS₂/p-degenerated BDD (DBDD) heterojunction device. The PL emission results for the heterojunction suggest strong potential for applications using yellow-light-emitting optoelectronic devices. From room temperature (RT) to 180 °C, the heterojunction exhibits typical rectification characteristics with good results for thermal stability, rectification ratio, forward current decrease, and reverse current increase. Compared with the n-MoS₂/p-lightly B-doped (non-degenerate) diamond heterojunction, the heterojunction demonstrates a significant improvement in both its rectification ratio and ideal factor. At 100 °C, the rectification ratio reaches the maximum value and is considered an ideal high temperature for achieving optimal heterojunction performance. When the temperature exceeds 140 °C, the heterojunction transforms into the Zener diode. The heterojunction’s electrical temperature dependence is due to the Fermi level shifting resulting in the weakening of the carrier interband tunneling injection. The n-MoS₂ NSs/p-DBDD heterojunction will broaden future research application prospects in the field of high-temperature consumption in future optoelectronic devices. Full article

Ensuring effective water purification is essential for addressing freshwater scarcity and achieving the United Nations Sustainable Development Goals (SDGs). An efficient hybrid mixture, composed of FeCr quantum dots doped into mesoporous silica SBA-15 support and activated carbon (AC) derived from olive mill solid wastes, has been developed for treating high optical density polluted aqueous environments. This hybrid, denoted as FeCr-SBA-15/AC, was examined for its efficacy in the adsorption and photo-Fenton degradation of met orange dye (MO), a model high-optical-density pollutant, under visible light exposure. Characterization of the prepared samples was conducted using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer–Emmett–Teller (BET) surface area analysis, diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Key parameters investigated included catalyst dosage, dye concentration, solution pH, and H₂O₂ concentration. Remarkably, the FeCr-SBA-15/AC hybrid exhibited superior photocatalytic activity, achieving a degradation efficiency of 97% for MO under optimized conditions (catalyst dosage = 0.75 g L⁻¹, dye concentration = 20 mg L⁻¹, pH = 5.47, and 0.5 mL H₂O₂) after 180 min of irradiation with visible light. This performance surpassed that of FeCr-SBA-15 alone by 20%, due to the synergistic effects of adsorption and photo-Fenton. The adsorption of MO onto AC followed the Freundlich model equilibrium isotherm, while the experimental data for the hybrid mixture aligned well with the pseudo-first-order Langmuir–Hinshelwood kinetic model with a rate constant of 0.0173 min⁻¹. The leaching of Cr in the solution was very low—0.1 ppm—which is below the detection limit. These findings underscore the potential of the synthesized FeCr-SBA-15/AC hybrid as a cost-effective, environmentally friendly, and highly efficient photo-Fenton catalyst for treating wastewater contaminated by industrial effluents. Full article