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Heteroatom doping, especially with elements of lower electronegativity and smaller atomic radius, can effectively modulate the electronic structure and surface properties of electron materials, facilitating the electrochemical performance of supercapacitors. Herein, we have designed boron-doped NiCoP nanoarrays grown on carbon cloth (B-NCP-CC) for supercapacitor cathode materials using a simple process method combining hydrothermal, calcined phosphating and boronation processes. The introduction of boron, with lower electronegativity (2.04) and smaller atomic radius (0.85 Å) than phosphorus (2.19 and 1.00 Å), induces electron redistribution and shortens the Ni/Co–B bonds, enhancing their redox activity and charge transfer kinetics. The boron doping greatly enables the B-NiCoP-CC-18 (NiCoP-CC borated for 18 h) cathode material to provide a high capacity of 801 C g−1. The assembled B-NiCoP-CC-18‖‖AC hybrid supercapacitor achieves a high energy density of 73.22 W h kg−1 at a power density of 963.8 W kg−1 and retains 90% capacity after 5000 cycles, significantly improving the stability of nickel-based materials. Besides, density functional theory (DFT) calculations further elucidate that the introduction of boron increases the d-band centers of Ni and Co in NiCoP, promoting the conductivity and enhancing the electrochemical properties. [ABSTRACT FROM AUTHOR]

Advancing the development of economical, high-performance, and durable non-precious metal electrocatalysts for oxygen evolution reaction (OER) holds critical significance. This study presents a self-supporting ternary metal phosphide (NiCoFe–P/NF) electrode developed by direct phosphating metal-organic frameworks (MOFs) precursor. Benefiting from a three-dimensional hierarchical porous structure, optimized electronic configuration, high electrical conductivity, and synergistic effect of multiple elements, the synthesized NiCoFe–P/NF electrocatalyst exhibits exceptional catalytic performance compared to the monometallic or bimetallic phosphides, achieving a low overpotential of 209 mV and a Tafel slope of 29 mV dec−1 at 10 mA cm−2 in 1 M KOH solution. In addition, the prepared catalyst exhibits superior stability and durability, as evidenced by its well-preserved morphology after 48 h of stability test. Furthermore, at a high current density of 100 mA cm−2, the long-term efficiency remains >90% even after 96 h. Density functional theory (DFT) calculations reveal that the high catalytic performance of the NiCoFe–P/NF catalyst is ascribed to modified electronic states and lower adsorption energy to the related species. This study not only presents the synthesis of extremely stable and active OER catalysts but also offers a novel and practical method for the development of new catalysts. [Display omitted] • Self-supporting trimetallic phosphide was investigated for OER. • NiCoFe–P/NF electrode provides superior OER activity and stability. • DFT calculations explain the origin of the high catalytic activity. • A chemically uniform trimetallic two-dimensional MOF served as the precursor. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (CN) materials have drawn remarkable research attention due to their extraordinary optical properties, which are especially promising for metal-free photocatalysis and photoluminescence. Herein we theoretically study the light absorption, electronic, and excitonic characteristics of covalently hybrid structures of CN quantum dots (CNQDs) and graphene quantum dots (GQDs). Density functional theory (DFT) and time-dependent DFT (TD-DFT) reveal that the relative size of CNQDs and GQDs and chemical modification to GQDs or CNQDs surface are critical determining the absorption and photocatalytic/photoluminescent performances of the as-studied structures. Importantly, the distribution position of the photoexcited electron–hole pair is found to depend on the relative size of CNQDs and GQDs, and chemical groups such as epoxy group may lead to distinct exciton distributions in the CNQD–GQD hybrid structures after attaching them to GQD or CNQD surface as compared to the case of pristine GQD and CNQD, indicating a non-negligible influence of unintended chemical reactions to CNQDs and/or GQDs under working conditions on the efficiencies of the materials for photocatalytic and photoluminescent applications. [ABSTRACT FROM AUTHOR]

Enhancing the photoconversion efficiency of graphene-based nanomaterials, especially graphene quantum dots (GQDs) and graphene nanoribbons (GNRs), has been a long pursued interest in diverse optical applications. Though chemical modification has shown its effectiveness to enhance the photoluminescence efficiencies of these materials, an accurate, comprehensive fundamental understanding of this enhancement is demanded for further development. Herein, density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations reveal that chemical species on the graphene nanostructure surface perturb the intrinsic electronic structures of the graphene moiety, with the perturbation manner and extent crucially depending on the binding positions of the species. In several configurations studied, the surface species lead to significantly enlarged oscillator strengths for the lowest optical transition (S 1 →S 0) and localized excitons (bounded electron and hole) compared to those of the pristine nanographene structures, indicative of their role in enhancing the photoluminescence as emission centers. By contrast, the surface species in the other configurations show trivial influence on the emission efficiency, as indicated by the only slightly altered electronic/excitonic structures and oscillator strengths. These results provide a fundamental understanding of the trap emission mechanism and also the tuning/engineering of photoluminescence efficiencies in relevant materials. Image 1 [ABSTRACT FROM AUTHOR]

[Display omitted] • 1D MWO 4 (M = Mn, Co, Cd) nanomaterials were synthesized by electrospinning method. • CoWO 4 nanotubes exhibited superior efficiency in degrading BPA under UV–Vis–NIR light. • The wide-spectrum responses mechanism for MWO 4 (M = Mn, Co, Cd) were explained by DFT. 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) MWO 4 (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 CoWO 4 and MnWO 4 samples were attributed to the metal-to-metal charge transfer mechanism, while the absorption of CdWO 4 sample may be referable to the ligand-to-metal charge transfer mechanism. In the near-infrared (NIR) region, the absorption of CoWO 4 and MnWO 4 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 CoWO 4 , MnWO 4 , and CdWO 4 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. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effect of atomic structures on GFA was studied by AIMD. • The average degree of LFFS is critical factor for enhancing GFA. • The effect of electronic structures on M s was studied by DFT. The poor glass forming ability (GFA) and magnetic properties of Co-based metallic glasses limit their applications. Herein the effects of similar element substitution of Co by Fe on the GFA and magnetic properties of Co 72.5-x Fe x Si 12.5 B 15 (x = 0, 4.5, 20, and 36) amorphous alloys were studied by experiments and density functional theory (DFT) calculations. The experimental results indicate that Fe substitution for Co improves the GFA of the studied metallic glasses, but in a concentration dependent manner, where Co 52.5 Fe 20 Si 12.5 B 15 shows the best GFA. Meanwhile, the saturated mass magnetization (M s) enhances with increasing Fe content. The atomic structures were analyzed by pair distribution function, coordination number, chemical short-range order, Voronoi polyhedron, and locally five-fold symmetry, and it was found that the highest average degree of the locally five-fold symmetry in Co 52.5 Fe 20 Si 12.5 B 15 is a critical factor for enhancing GFA, which improves the stability of the local atomic structures by increasing the packing density and reducing the potential energy. Density of states and magnetic moments calculated for the four metallic glasses manifest that the larger magnetic moment of Fe atoms and gradual increase in the contribution of the Fe 3d state are responsible for the increase in the M s with Fe content. This work links the GFA and magnetic properties of Co–Fe–Si–B metallic glasses with their atomic/electronic structures, providing reference for designing Co-based metallic glasses with good GFA and enhanced magnetism. [ABSTRACT FROM AUTHOR]