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Due to importance of the gas uptake topic in environment and energy issues, this work was performed for investigating ozone (Oz) gas uptake by means of a beryllium oxide (BeO) nanoflake. To this aim, density functional theory (DFT) calculations and the quantum theory of atoms in molecules (QTAIM) analysis were performed. The monolayer BeO nanoflake was decorated by a HEME-like N4Fe region to prepare an interacting region towards the Oz uptake. Accordingly, three models were optimized based on configurations of Oz molecule relaxation at the BeO surface, in which two types of O... Fe and O... N interactions were observed. In this case, Oz3@BeO model was involved with two mentioned types of interactions and three occurred interaction between Oz and BeO making it as the strongest bimolecular formation model of Oz@BeO. Moreover, electronic molecular orbital features indicated that the models formations could be also related to sensor functions by variations of electric conductivity because of Oz gas uptake. As a consequence, the investigated BeO nanoflake of this work was proposed for employing in Oz gas uptake for different purposes. [ABSTRACT FROM AUTHOR]

Water-electrolysis intends a favorable green technology to hold the worldwide energy and ecological disaster, but its efficacy is significantly restricted by the slow reaction kinetics of both the anodic oxygen evolution reaction (OER) and cathodic hydrogen evolution reaction (HER). Herein, the fabrication of multi-cation incorporated Fe2+/3+/Co2+ species into selenides nanorods (Fe@Co/Se 2 -NRs) and corresponding analysis of their catalytic activity for electrochemical (EC) and solar-driven water splitting as a purpose of the composition are reported. This efficient approach can fabulously endow electronic structure modulation and the direct evidence of electron-transfer-route between transition-metals and selenides, which are vital to improving the electrocatalytic activity, has never been confirmed before. For the first time, we explored the electron-transfer route of intensely-coupled Fe@Co/Se 2 -NRs catalyst, in which the Fe2+/3+/Co2+ species strongly-coupled to selenide through the Fe-coordinated Co-bridged-bond. Finally, density functional theory calculations disclose that the multi-cation doping effects into selenides are vital for enhanced electrocatalytic performance. [Display omitted] • The self-templated approach developed for bifunctional OER/HER electrocatalysts. • Iron-Cation-Coordinated Cobalt-Bridged-Selenides Nanorods structure increases the number of active sites. • The Fe@Co/Se 2 -nanorods reveal superior bifunctional OER/HER performance. • Requires only 1.5 V@10 mA cm−2 for electrochemical and solar-to-hydrogen conversion efficacy of ∼ 7.0% for water splitting. • DFT and XAS analysis exposed the electron-transfer route of intensely coupled Fe@Co/Se 2 -NRs. [ABSTRACT FROM AUTHOR]

To safely cope with the hazardous methylene blue (MB) and rhodamine (RhB) dyes in wastewater, ZnFe 2 O 4 has shown promise as attractive photocatalytic degradation material. Therefore, we synthesized CQDs-decorated ZnFe 2 O 4 microspheres and successfully degraded MB and RhB dyes under UV light. The CQDs/ZnFe 2 O 4 composites exhibited superior performance as compared to pure ZnFe 2 O 4 , achieving nearly 100% degradation of MB in 60 min and 95% degradation of RhB in 80 min. Additionally, the CQDs/ZnFe 2 O 4 material was found stable after four consecutive cycles during the photocatalytic activity. Density functional theory calculations revealed that CQDs generated new gap states near the Fermi level, enhancing the charge separation and conductivity of the composites. The photocatalytic mechanism involved the generation of holes, . OH and . O 2 radicals as the active species. These results demonstrate that CQDs/ZnFe 2 O 4 composites can be promising candidates in wastewater treatment along with other wide range of applications. • A facile impregnation-thermal method was developed to fabricate CQDs-decorated ZnFe 2 O 4 microspheres. • The active species in the photocatalytic system are confirmed as holes, ●OH, and ●O 2 − by the trapping experiments. • CQDs/ZnFe 2 O 4 microspheres showed superior performance to pure ZnFe 2 O 4 , achieving nearly 100% degradation of MB in 60 min and 95% degradation of RhB in 80 min. • Intrinsic photocatalytic degradation mechanism of CQDs/ZnFe 2 O 4 MSs towards organic dyes is tentatively proposed. [ABSTRACT FROM AUTHOR]

Photo/electrochemical fixation of atmospheric nitrogen (N 2) into valuable chemicals is a favorable strategy to utilize the abundant natural resources for efficient catalysis. It is extremely desirable to discover immensely active, durable, and selective catalysts for effective photoelectrochemical N 2 fixation. Herein, low-cost, non-noble metal-based porous Mo-doped WO 3 @CdS hollow microspheres as hierarchical heterostructures were synthesized that can effectively catalyze and reduce the gaseous N 2 into ammonia (NH 3). High Faradaic efficiency (36.72%) and fast average ammonia yield rate (38.99 µg h−1 mg cat −1) were observed at −0.3 V vs. RHE in the neutral solution at ambient conditions. Mo-doping and interconnected porous heterostructures synergistically deliver sufficient catalytic sites for effective photoelectrocatalytic N 2 reduction. Furthermore, density functional theory (DFT) calculations validate that the Mo-doping WO 3 is advantageous to decrease the energy barrier for N 2 activation and protonation. Therefore, this work demonstrates the rational construction of transition metals-based hierarchical hollow photoelectrocatalysts towards efficient artificial N 2 fixation. [Display omitted] • Porous Mo-WO 3 @CdS hierarchical hollow microspheres heterostructures (HMHs) are synthesized in the present work. • Hierarchical hollow microstructures increase the active surface area and accessibility to active sites. • Strong absorbance of light due to hollow Mo-WO 3 structures enhanced the light-harvesting capability and play a key role in the PEC N 2 reduction. • The hierarchical heterostructures demonstrated enhanced photoelectrocatalytic activity towards high FE and NH 3 yield. [ABSTRACT FROM AUTHOR]

[Display omitted] • The homogeneous nanotube of BC 3 NT is a highly active site for the adsorption of EBT dye. • B top site of BC 3 NT is the dominant active site for EBT dye adsorption. • The adsorption energy of EBT dye on the BC 3 NT surface was about −37.67 kcal/mol. Herein, we aim to investigate the structure, intermolecular forces, electronic features, and durability in a solution of complexes formed between Eriochrome black T dye (EBT) and BC 3 nanotube (BC 3 NT) by density functional theory modeling. Possible applications for the removal of EBT were studied with the help of BC 3 NT. The energy of adsorption is about −36.76 kcal/mol for the interaction between EBT and a boron atom of the tube via its O atom. The electrical features of BC 3 NT are significantly affected by EBT, making them appropriate for the adsorption process. Also, donor–acceptor interaction mainly controlled the adsorption mechanism of EBT. This work, on the one hand, boosts the enhancement of low-cost and tolerable heteroatom carbon-based materials. On the other hand, it systematically investigates the mechanism of adsorption heteroatom carbonaceous structures for EBT. [ABSTRACT FROM AUTHOR]

This work was performed to examine an idea about full chelation of Iron (Fe) by well-known favipiravir (Fav) as a possible mechanism of action for medication of COVID-19 patients. To this aim, formations of Fe- mediated dimers of Fav were investigated by performing density functional theory (DFT) computations of electronic and structural features for singular and dimer models. The results indicated that the models of dimers were suitable for formation, in which two cis (D1) and trans (D2) models were obtained regarding the configurations of two Fav counterparts towards each other. Energy results indicated that formation of D1 was slightly more favorable than formation of D2. Molecular orbital features affirmed hypothesized interacting sites of Fav for Fe-mediated dimers formations, in which atomic charges and other molecular orbital related representations affirmed such achievements. Moreover, detection of such dimer formation was also possible by monitoring variations of molecular orbitals features. As a consequence, formations of Fe-mediated dimers of Fav could be achievable for possible removal of excess of Fe as a proposed mechanism of action for Fav in medication of COVID-19 patients. [ABSTRACT FROM AUTHOR]

• A Novel layer-stacked well designed and highly crystalline 2D MOF named as Co 3 (HADQ) 2 MOF. • This Unique MOF features Co-N 4 motifs along with pyridinic Nitrogen (total N content: 28.6 at. %) as the active sites for ORR. • Outclass most of the electrocatalysts with a high activity (E 1/2 = 0.836 V vs. RHE, n = 3.93, and j L = 5.31 mAcm−2) in acidic media. • Exceptionally electrochemical stability up to 20,000 cycles for ORR in an acidic media at 0.29 pH. Efficient and robust electrocatalysts for acidic Oxygen reduction reaction (ORR) is crucial for the proton exchange membrane hydrogen fuel cells. However, the current electrocatalysts suffer from the stability issues in the acidic enviorment during ORR. Herein, we introduce a new layer-stacked two-dimensional (2D) metal-organic framework (MOF), Co 3 (HADQ) 2 (HADQ = 2,3,6,7,10,11-hexaamine dipyrazino quinoxaline), synthesized for the first time. This novel MOF material shows the extremely high conductivity of 8,385.744 S/m with extraordinary activity (E 1/2 = 0.836 V vs. RHE, n = 3.93, and j L = 5.31 mAcm−2) and an exceptional stability (up to 20,000 cycles) as the electrocatalyst for ORR in an acidic media (pH = 0.29), outperforming most of the state of the art Metal-N-C and single-atom electrocatalysts for acidic ORR. Density functional theory calculations indicate that the Co-sites are the active sites. We propose that Co 3 (HADQ) 2 is a promising model catalyst for mechanistic studies of acidic ORR, due to its well defined and tunable structure. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new strategy is adopted to prepare a 3D hierarchical smart scaffold (CNCs/NF). • Obtained O 0.075 -V 2 O 5 /CNCs/NF composite enable high capacitive performance. • Doping of S into CNCs composite exhibits enhanced performance. • Asymmetric supercapacitor (ASCs) was assembled. • DFT calculations validate the experimental results. Electronic structural engineering via integration of oxygen deficiencies and a variety of dopants in metal oxide electrodes has fascinated the research interest for developing next-generation supercapacitors. Herein, by incorporating Ni dopants and creating O vacancies, it has thoroughly been explored the potential of vanadium oxide (V 2 O 5) nanosheets anchored on the carbon nanocoils (CNCs) grown on nickel foam (NF) for supercapacitor electrodes (O V -Ni-V 2 O 5 /CNCs/NF). We validate a synergistic effect provided by heterostructure designed with multifunctional nano geometries. It is found that O vacancies and Ni dopants alter the electronic states of V 2 O 5 with enhanced electrical conductivity and enriched redox active sites. We optimized O vacancies and achieved a specific capacity of 3485F g−1 (1742.5C g−1) at 1 A/g, representing ∼ 3.8 × higher compared to the best prior report. Furthermore, an asymmetric supercapacitor device was assembled with binder-free electrodes, using O 0.075 -V 2 O 5 /CNCs/NF as a cathode and sulfur-doped CNCs as an anode, which delivered a high energy density of 144 W h kg−1 and long-term stability of 5000 cycles, which is superior to most of the previous studies. This study paves a rational strategy to design high-performance electrodes for next-generation supercapacitors and other energy storage technologies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe-single atom anchored on carbon nanotubes catalyst was fabricated. • The catalyst exhibits excellent ORR catalytic activity in alkaline and acidic media. • The activity is boosted by the decorated Fe-N 4 on carbon nanotubes. Developing cost-effective and high-performance non-precious electrocatalysts for ORR in acidic and alkaline media is an urgent need for clean energy generation. A significant improvement in the ORR performance has been realized by the single-atom catalysts (SACs). However, activity deterioration caused by the dissolution of catalyst structure is still a lingering challenge. Herein, we report a simple strategy for protecting the structure of SAC by implanting/decorating Fe-ZIF-derived carbon nanotubes with Fe-N 4 , denoted as FeSA@CNTs. The as-developed FeSA@CNTs catalyst exhibits an outstanding ORR activity in an alkaline medium with onset potential (E o) = 0.998 V and half-wave potential E 1/2 = 0.898 V, which are 28 mV and 29 mV higher than commercial 20% Pt/C, respectively. Moreover, FeSA@CNTs in an acidic medium show an impressive high half-wave potential (E 1/2 = 0.8290 V) comparable to Pt/C (E 1/2 = 0.8292 V) which is better than most recently reported ORR catalysts. The density functional theory (DFT) validates that the smaller difference in the energy orbitals of Fe in Fe-N 4 and O 2 improved the electron transfer onto the reaction intermediate (OH*) in the rate-determining step, which provides the higher catalytic activity for FeSA@CNTs' in both acidic and alkaline media. [ABSTRACT FROM AUTHOR]

[Display omitted] • CaFe LDH intercalated with tolyl-triazole inhibitor (TTA) was synthesized using the in-situ intercalation co-precipitation approach. • g-C 3 N 4 was then used to fabricate the nanohybrid of CaFe-TTA LDH and g-C 3 N 4 via simple sonication and stirring. • The prepared materials were used as nanofillers in epoxy coatings for corrosion protection application. • The electrochemical and salt-spray test results revealed the excellent protection and self-healing activity of the coating. • The DFT simulation supported the corrosion protection mechanism and reaction kinetics during the corrosion process. Nanofillers are considered the most aspiring materials in recent years for the anti-corrosion functional coatings applied to the metal surface. Herein, the CaFe-tolyl-triazole layered double hydroxide (CaFe-TTA LDH) nanoplates and CaFe-tolyl-triazole layered double hydroxide@graphitic carbon nitride (CaFe-TTA LDH@g-C 3 N 4) nanohybrids were successfully prepared using the facile approaches. The prepared CaFe-TTA LDH nanoplates/CaFe-TTA LDH@g-C 3 N 4 nanohybrids were incorporated into the epoxy resin to develop corrosion-resistant nanocomposite coatings. The resistances at 0.01 Hz (|Z| 0.01) of EP/CaFe-TTA LDH and EP/CaFe-TTA LDH@g-C 3 N 4 samples were reduced by one order of magnitude after 60 days of immersion in 3.5% NaCl solution (from 5.49 × 108 Ω cm2 to 4.42 × 107 Ω cm2 and from 1.18 × 109 Ω cm2 to 2.25 × 108 Ω cm2 respectively), compared to the pristine EP coating, which decreased approximately two orders of magnitude (from 2.61 × 108 Ω cm2 to 7.69 × 106 Ω cm2). The localized electrochemical impedance spectroscopy (LEIS) and salt spray tests further explored the self-healing activity of the coatings and revealed that the scratched EP/CaFe-TTA LDH@g-C 3 N 4 coatings maintained excellent corrosion resistance. The pull-off adhesion test showed an improved adhesion strength as compared to the pristine epoxy coating. Moreover, the density functional theory simulation confirmed the reaction mechanism of the nanofillers during the corrosion process. Hence, the results revealed that the EP/CaFe-TTA LDH@g-C 3 N 4 -based coatings delivered superior barrier/active inhibition performance due to the labyrinth and self-healing effect of nanofillers, suggesting a promising avenue for the development of a variety of nanocomposite coatings for various functional applications. [ABSTRACT FROM AUTHOR]