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• Predict a new two-dimensional antiferromagnetic material (2D pyrite) and its property. • Explain the magnetism of two-dimensional FeS 2 in metal crystal-field theory. • Regulate the electronic property of two-dimensional pyrite by strain engineering. In this paper, a new two-dimensional antiferromagnetic material, 2D pyrite, was reported, which exhibited a completely planar pentagonal structure. Pentagonal FeS 2 were revealed by the first-principles calculation with GGA + U (U eff = 2 eV) method and proved excellent mechanically stable, dynamically stable and thermally stable. Intriguingly, this single-layer structure was perfectly in line with the geometric characteristic of "Cairo pentagon". Completely different from the bulk pyrite, the two-dimensional FeS 2 was proved an amazing magnetic semiconductor and the ground state configuration of the magnetic coupling is antiferromagnetic with a 0.31 eV band gap. Considering the spin–orbit coupling effect, the magnetocrystalline anisotropy energy (MAE) in different orientation was calculated and the easy axis was proved along the c axis. The highest MAE in our GGA + U calculation could reach 454.77 μeV per Fe atom. Furthermore, biaxial strain was applied to regulate the electronic structure of 2D FeS 2 and the results suggested that 2D pyrite would be converted into ferromagnetic configuration when the strain ranging from 2.2% to 5.0%. Therefore, our research predicted a new two-dimensional spintronic materials and proved a new thought for the application of pyrite. [ABSTRACT FROM AUTHOR]

A facial and efficient process for the synthesis of porous Zn x Co 3-x O 4 hollow nanoboxes using zeolitic imidazolate frameworks as precursors has been demonstrated in this study, the as-prepared electrodes are applied for both LIBs and SIBs. The porous structure and hollow interspace can not only provide valuable channels and voids for lithium/sodium ion transfer and storage, but also buffer the stress/strain caused by volume changes. Besides, the enhanced electrical conductivity can effectively improve the reaction kinetics by synergistic effect of the binary metal oxides, as studied by density functional theory (DFT) calculations and storage mechanism studies. For lithium-ion batteries, the electrode exhibits an ultrahigh reversible capacity of 1141.7 mAh g−1, with an initial coulombic efficiency of 95.6%, and an ultralong life up to 800 cycles at 500 mA g−1. Even at a high current of 3.0 A g−1, a superior capacity of 484 mAh g−1 can be achieved. When using for sodium-ion battery anode, the reversible capacity is remained at 310 mAh g−1 after 100 cycles at 200 mA g−1, with a capacity retention of 90.4%. The electrode materials show long-term cycle stability and excellent rate capability, which gives a bright prospect for energy storage devices. • The unique structure can accelerate the transportation of ions. • The synergistic effect shows enhanced electrical conductivities and ion diffusions. • The general phenomenon of the capacities rise is discussed in detail. • The electronic structures of Zn/Co oxides were studied by density functional theory (DFT) calculations. [ABSTRACT FROM AUTHOR]

Porous organic polymers (POPs) constructed through covalent bonds have raised tremendous research interest because of their suitability to develop robust catalysts and their successful production with improved efficiency. In this work, we have designed and explored the properties and catalytic activity of a template-free-constructed, hydroxy (-OH) group-enriched porous organic polymer (Ph-POP) bearing functional Pd nanoparticles (Pd-NPs) by one-pot condensation of phloroglucinol (1,3,5-trihydroxybenzene) and terephthalaldehyde followed by solid-phase reduction with H 2 . The encapsulated Pd-NPs rested within well-defined POP nanocages and remained undisturbed from aggregation and leaching. This polymer hybrid nanocage Pd@Ph-POP is found to enable efficient liquid-phase hydrodeoxygenation (HDO) of acetophenone (AP) with high selectivity (99%) of ethylbenzene (EB) and better activity than its Pd@Al 2 O 3 counterpart. Our investigation demonstrates a facile, scalable, catalyst-template-free methodology for developing novel porous organic polymer catalysts and next-generation efficient greener chemical processes from platform molecules to produce value-added chemicals. With the aid of comprehensive in situ ATR-IR spectroscopy experiments, it is suggested that EB can be more easily desorbed in a solution, reflecting from the much weaker but better-resolved signal at 1494 cm -1 in Pd@Ph-POP compared to that in Pd@Al 2 O 3 , which is the key determining factor in favoring an efficient catalytic mechanism. Density functional theory (DFT) calculations were performed to illustrate the detailed reaction network and explain the high catalytic activity observed for the fabricated Pd@Ph-POP catalyst in the HDO conversion of AP to EB. All of the hydrogenation routes, including direct hydrogenation by surface hydrogen, hydrogen transfer, and the keto-enol pathway, are evaluated, providing insights into the experimental observations. The presence of phenolic hydroxyl groups in the Ph-POP frame structure facilitates the hydrogen-shuttling mechanism for dehydration from the intermediate phenylethanol, which was identified as a crucial step for the formation of the final product ethylbenzene. Besides, weaker binding of the desired product ethylbenzene and lower coverage of surface hydrogen atoms on Pd@Ph-POP both contributed to inhibiting the overhydrogenation reaction and explained well the high yield of EB produced during the HDO conversion of AP on Pd@Ph-POP in this study.

The adsorption properties and microscopic mechanism of CO 2 adsorption in 1,1-dimethyl-1,2-ethylenediamine (dmen) functionalized M 2 (dobpdc) (dobpdc 4- =4,4'-dioxidobiphenyl-3,3'-dicarboxylate; M = Mg, Sc-Zn) have been completely unveiled for the first time via comprehensive investigations based on first-principles density functional theory (DFT) calculations. The results show that for the primary-primary amine, dmen prefers to interact with the open metal site of M 2 (dobpdc) via the end with smaller steric hindrance. The binding energies of dmen with MOFs are in the range of 104-174 kJ/mol. In presence of CO 2 , it fully inserts into the metal-N bond, forming ammonium carbamate. The CO 2 binding energies vary from 53 to 89 kJ/mol, showing strong metal dependence. Among the 11 metals, dmen-Sc 2 (dobpdc) and dmen-Mg 2 (dobpdc) have the highest CO 2 binding energies of 89 and 84 kJ/mol, respectively, and may have large CO 2 adsorption capacity for practical applications. More importantly, the microscopic CO 2 capture process of dmen-M 2 (dobpdc) is revealed at the atomic level. The whole reaction process includes two steps, that is, formation of zwitterion intermediate (step 1) and rearrangement of the zwitterion intermediate (step 2). The first step in which nucleophilic addition between CO 2 and the metal-bound amine and proton transfer from the metal-bound amine to free amine simultaneously occur is a rate-determining step, with higher energy barriers (0.99-1.35 eV). The second step with much lower barriers (maximum of 0.16 eV) is extremely easy, which can promote the whole CO 2 uptake process in dmen-M 2 (dobpdc). This study provides a fundamental understanding of the underlying mechanism of the rather complicated CO 2 adsorption process and sheds important insights on design, synthesis, and optimization of highly efficient CO 2 capture materials.

This manuscript reports the improved synthesis of the α,α,α,α isomer of tetra-p-iodophenyl tetra-methyl calix[4]pyrrole and the X-ray characterization of two solvate polymorphs. In the solid state, the calix[4]pyrrole receptor adopts the cone conformation, including one acetonitrile molecule in its aromatic cavity by establishing four convergent hydrogen bonds between its nitrogen atom and the four pyrrole NHs of the former. The inclusion complexes pack into rods, displaying a unidirectional orientation. In turn, the rods form flat 2D-layers by alternating the orientation of their p-iodo substituents. The 2D layers stack on top of another, resulting in a head-to-head and tail-to-tail orientation of the complexes or their exclusive arrangement in a head-to-tail geometry. The dissimilar stacking of the layers yields two solvate polymorphs that are simultaneously present in the structures of the single crystals. The ratio of the two polymorph phases is regulated by the amount of acetonitrile added to the chloroform solutions from which the crystals grow. Halogen bonding interactions are highly relevant in the crystal lattices of the two polymorphs. We analyzed and characterized these interactions by means of density functional theory (DFT) calculations and several computational tools. Remarkably, single crystals of a solvate containing two acetonitrile molecules per calix[4]pyrrole were obtained from pure acetonitrile solution. [ABSTRACT FROM AUTHOR]

Suppressing lithium dendrites in carbonate electrolyte remains a grand challenge for high voltage lithium metal batteries. The role of adhesion between the interfacial layer and the lithium metal in controlling lithium growth is often overlooked. Here, we find that the adhesion energy significantly influences lithium dendrite growth by the phase-field simulations, and LiAl is an attractive material with strong adhesion with lithium metal by density functional theory (DFT) calculations. Then a simple solution process is developed to form conformal nanostructured LiAl interfacial layer on the lithium metal surface. With the nanostructured LiAl alloy-based interfacial layer, the Li/Li symmetric cell can be cycled stably for more than 1100 times at 5 mA/cm2, 1 mAh/cm2 with a low overpotential of 170 mV. For the LiNi 1/3 Co 1/3 Mn 1/3 O 2 /Li full cell, this interfacial layer improves the capacity retention from 59.8% to 88.7% for 120 cycles at 1 C rate, and for the LiFePO 4 /Li system, the modified lithium anode also improves capacity retention from 79.5% to 99.4% after 150 cycles. This study represents a new approach to enhance the performance of lithium anode for rechargeable batteries with high voltage and high energy density. Image 1 • The lithium dendrites could be suppressed effectively with high interfacial adhesion energy between interfacial layer and lithium metal matrix. • The LiAl alloy interfacial layer with high interfacial adhesion energy was formed in situ on lithium surface. • It displays excellent performance in Li/Li, LFP/Li and NCM/Li cell with nanostructured interface in carbonate electrolyte without any additives. [ABSTRACT FROM AUTHOR]

• A reed-derived biochar modified nickel-foam cathode was elaborated. • Sulfamerazine (SMR) was firstly degraded by electro-Fenton. • Fe2+- tetrapolyphosphate has a relative higher OH generation ability. • Absolute rate constant for oxidation of SMR by OH= (3.4 ± 0.09) × 109 M−1 s−1. • DFT suggested hydroxylation of SMR was dominant during its oxidation degradation. A nickel-foam cathode modified by a self-nitrogen-doped biochar derived from waste giant reed was synthesized. The fabricated cathode (B@Ni-F) proved to be with high oxygen reaction reactive (ORR) reactivity and H 2 O 2 selectivity (70.41%) owing to the enrichment of oxygen functional groups and pyridinic N when low-temperature pyrolyzed biochar was incorporated. The charge transfer resistance of B@Ni-F decreased to 7.18 Ω, which was 95.7 Ω for the original nickel-foam, proving by electrochemical impedance spectroscopy (EIS). Expectedly, Its H 2 O 2 accumulation improved 14 times, thus making it comparable with commonly used electrodes like carbon cloth and graphite plate. Subsequently, B@Ni-F cathode and iron-foam (Fe-F) catalyst were firstly used in the electro-Fenton (EF) process for sulfamerazine (SMR) degradation. Double-functional polyphosphate electrolytes including tetrapolyphosphate (4-TPP), tripolyphosphate (3-TPP), pyrophosphate (PP) and Na 3 PO 4 were compared with the conventional Na 2 SO 4 electrolyte in EF for SMR degradation. The absolute rate constant for oxidation of SMR by OH was determined to be (3.4 ± 0.09) × 109 M−1 s−1. SMR degradation enhancement in the presence of polyphosphate-based electrolytes is associated with bulk OH generation from Fe2+- polyphosphate ligand complexes via O 2 activation. The Fe2+-3-TPP complexes have relatively higher oxidation ability compared to Fe2+-PP, Fe2+-PO 4 species. A plausible SMR oxidation pathway is proposed based on the by-products detected by UPLC-MS/MS and density functional theory (DFT) calculations. The dominant SMR degradation pathway was hydroxylation of aniline residue of SMR, followed with the cleavage of S N and then breakage of aromatic rings. [ABSTRACT FROM AUTHOR]

The ability to incorporate high content of interstitial oxygen ions (Oi) in La1+xSr1‐xGa3O7+0.5x melilite owing to the good size match between La3+ and Sr2+ ions is well documented. Here, the complete substitution of Sr2+ by Pb2+ lone‐pair cations results in a significant loss of this ability, even though Sr2+ and Pb2+ have almost the same effective ionic radius. To explore the fundamental mechanism underlying this result, density functional theory (DFT) calculations are performed on both the LaSrGa3O7‐based and LaPbGa3O7‐based materials, revealing a new chemical bonding effect on the incorporation of mobile oxygen interstitial defects in melilites. For LaSrGa3O7‐based melilites, the interstitial oxygens have cooperatively weak antibonding interactions with the framework oxygen atoms (Of). This antibonding Oi‐Of interaction pushes Oi toward a 3‐linked Ga ion, enhancing the covalent bonding between this Ga ion and Oi. In addition, the antibonding Oi–Of interaction makes the oxygen interstitial defects and framework atoms highly active, benefiting the migration of defects. In contrast, for LaPbGa3O7‐based materials, the 6s2 electrons of Pb2+ point toward the c‐axis and form antibonding with framework O2−. This antibonding projects into the tunnel void, thereby directly hindering the entrance of interstitial oxygen atoms into the pentagonal rings. [ABSTRACT FROM AUTHOR]

Charge injection barriers at metal/organic interfaces can be tuned by modifying the work function of metallic electrodes using self‐assembled monolayers (SAMs) of polar molecules. An interesting example of polar molecules is offered by donor–acceptor (D–A) dyads based on ferrocene (Fc) as electron‐donor unit and either a polychlorotriphenylmethyl radical or a polychlorotriphenylmethane as electron‐acceptor units, connected by a π‐conjugated vinylene bridge. The D–A radical exhibits high chemical and thermal stability and presents different electronic, optical, and magnetic properties with respect to the closed‐shell form. The magnitude of the shift in the charge injection barriers for these two D–A systems is estimated by means of surface potential measurements performed by Kelvin probe force microscopy. The experimental data are compared with density functional theory calculations, which evidence the importance of the molecular dipole moments and polarizabilities to understand the experimental values. In order to achieve high work function shifts of metals upon SAM formation, the molecules forming the SAM have to exhibit both a high permanent dipole moment and a low polarizability along the direction normal to the substrate. In presence of polarizable molecules, the work function shifts can be enhanced by reducing the intermolecular interactions; by using mixed SAMs with active molecules embedded into a passive matrix. [ABSTRACT FROM AUTHOR]

Lithium–sulfur batteries are currently being explored as promising advanced energy storage systems due to the high theoretical specific capacity of sulfur. However, achieving a scalable synthesis for the sulfur electrode material whilst maintaining a high volumetric energy density remains a serious challenge. Here, a continuous ball‐milling route is devised for synthesizing multifunctional FeS2/FeS/S composites for use as high tap density electrodes. These composites demonstrate a maximum reversible capacity of 1044.7 mAh g−1 and a peak volumetric capacity of 2131.1 Ah L−1 after 30 cycles. The binding direction is also considered here for the first time between dissolved lithium polysulfides (LiPSs) and host materials (FeS2 and FeS in this work) as determined by density functional theory calculations. It is concluded that if only one lithium atom of the polysulfide bonds with the sulfur atoms of FeS2 or FeS, then any chemical interaction between these species is weak or negligible. In addition, FeS2 is shown to have a strong catalytic effect on the reduction reactions of LiPSs. This work demonstrates the limitations of a strategy based on chemical interactions to improve cycling stability and offers new insights into the development of high tap density and high‐performance sulfur‐based electrodes. FeS2/FeS/S composites for Li–S batteries with high tap density are prepared via a scalable ball‐milling route. The binding direction between polysulfides and sulfur hosts is considered, concluding that weak or even no interactions exist if only one Li atom bonds with the sulfur atoms of FeS2 and FeS, indicating the limitations of a strategy based on chemical interactions. [ABSTRACT FROM AUTHOR]

Lithium sulfide (Li 2 S) is a promising cathode material with high capacity, which can be paired with nonlithium metal anodes such as silicon or tin so that the safety issues caused by the Li anode can be effectively avoided. However, the Li 2 S full cell suffers from rapid capacity degradation due to the dissolution of intermediate polysulfides. Herein, a Li 2 S/Si full cell is designed with a Li 2 S cathode incorporated by titanium nitride (TiN) polysulfide immobilizer within parallel hollow carbon (PHC). This full cell delivers a high initial reversible capacity of 702 mAh g Li2S -1 (1007 mAh g sulfur -1 ) at 0.5 C rate and excellent cyclability with only 0.4% capacity fade per cycle over 200 cycles. The long cycle stability is ascribed to the strong polysulfide anchor effect of TiN and highly efficient electron/ion transport within the interconnected web-like architecture of PHC. Theoretical calculations, self-discharge measurements, and anode stability experiments further confirm the strong adsorption of polysulfides on the TiN surface. The present work demonstrates that the flexible Li 2 S cathode and paired Si anode can be used to achieve highly efficient Li-S full cells., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Enabling long cyclability of high-voltage oxide cathodes is a persistent challenge for all-solid-state batteries, largely because of their poor interfacial stabilities against sulfide solid electrolytes. While protective oxide coating layers such as LiNbO 3 (LNO) have been proposed, its precise working mechanisms are still not fully understood. Existing literature attributes reductions in interfacial impedance growth to the coating's ability to prevent interfacial reactions. However, its true nature is more complex, with cathode interfacial reactions and electrolyte electrochemical decomposition occurring simultaneously, making it difficult to decouple each effect. Herein, we utilized various advanced characterization tools and first-principles calculations to probe the interfacial phenomenon between solid electrolyte Li 6 PS 5 Cl (LPSCl) and high-voltage cathode LiNi 0.85 Co 0.1 Al 0.05 O 2 (NCA). We segregated the effects of spontaneous reaction between LPSCl and NCA at the interface and quantified the intrinsic electrochemical decomposition of LPSCl during cell cycling. Both experimental and computational results demonstrated improved thermodynamic stability between NCA and LPSCl after incorporation of the LNO coating. Additionally, we revealed the in situ passivation effect of LPSCl electrochemical decomposition. When combined, both these phenomena occurring at the first charge cycle result in a stabilized interface, enabling long cyclability of all-solid-state batteries.

Herein, a metal-organic framework (MOF)/polythiophene (PTh)-derived S-doped carbon is successfully designed and prepared employing zeolitic imidazolate frameworks (ZIF-8/ZIF-67) and thiophene (Th) as precursors. The S-doped carbon presents a neuronlike three-dimensional network structure (3DSC). The 3DSC delivers extra-high capacities (225 mAh/g at 5000 mA/g after 3000 cycles) and excellent endurance ability of current changes when applied in Na-ion batteries (SIBs). Moreover, when the 3DSC-700 anode is coupled with a sodium vanadium phosphate cathode to construct a Na-ion full cell, after 50 cycles, a high capacity of ∼229.64 mAh/g is obtained at 100 mA/g. Electrochemical impedance spectroscopy analysis, density functional theory calculations, and pseudocapacitance contributions are adopted to investigate the excellent sodium storage mechanism of the 3DSC electrode. A new idea has been provided in this work to open up the possibility of MOF materials and carbon-based materials applications in SIBs in the future.

The development of functional materials for the highly efficient capture of radionuclides, such as uranium from nuclear waste solutions, is an important and challenging topic. Here, few‐layered N, P, and S codoped graphene‐like carbon nanosheets (NPS‐GLCs) that are fabricated in the 2D confined spacing of silicate RUB‐15 and applied as sorbents to remove U(VI)ions from aqueous solutions are presented. The NPS‐GLCs exhibit a large capacity, wide pH suitability, an ultrafast removal rate, stability at high ionic strengths, and excellent selectivity for U(VI) as compared to multiple competing metal ions. The 2D ultrathin structure of NPS‐GLCs with large spacing of 1 nm not only assures the rapid mass diffusion, but also exposes a sufficient active site for the adsorption. Strong covalent bonds such as POU and SOU are generated between the heteroatom (N, P, S) with UO22+ according to X‐ray photoelectron spectroscopy analysis and density functional theory theoretical calculations. This work highlights the interaction mechanism of low oxidation state heteroatoms with UO22+, thereby shedding light on the material design of uranium immobilization in the pollution cleanup of radionuclides. Few‐layered N, P, and S codoped graphene‐like carbon nanosheets are produced in the 2D confined spacing of silicate RUB‐15. With the aid of X‐ray photoelectron spectroscopy analysis and density functional theory calculation, the strong covalent bonds (POU and SOU) are proved to be the key for the excellent performance and selectivity on UO22+ fixation. [ABSTRACT FROM AUTHOR]

The development of high‐performance transparent conductors (TCs) is critical to various technologies from transparent electronics to solar cells. Whereas n‐type TCs have been extensively applied in many electronic devices, their p‐type counterparts have not been largely commercialized due to the lack of ideal materials. Combining atomic replacement and first‐principles calculations, seven stable layered double perovskites are identified, i.e., Cs4CuSb2Cl12‐like Cs4M2+B3+2XVII12 compounds as promising p‐type TCs with sufficiently large bandgaps, delocalized wavefunction distribution with s‐orbital components in valence band maximum (VBM) and the antibonding character of VBM to ensure their optical transparency, light hole effective masses, and intrinsic good p‐type conductivities, respectively. Taking Cs4CdSb2Cl12 as a representative example, it is demonstrated that under Cd‐poor (Cl‐rich) conditions, Cs4CdSb2Cl12 could exhibit excellent p‐type conductivity with high hole concentration, contributed by the intrinsic shallow‐acceptor CdSb with extremely low formation energy. Generally, the other 6 Cs4M2+B3+2XVII12 compounds exhibit similar intrinsic p‐type defect properties as Cs4CdSb2Cl12, which could rank them as the top p‐type TCs discovered or predicted until now. Combining atomic replacement and first‐principles calculations, seven Cs4M2+B3+2XVII12 layered perovskite compounds as promising intrinsic p‐type transparent conductors are identified. They exhibit good crystallographic, dynamical and thermodynamic stabilities, optical transparency, light hole effective masses, and intrinsic good p‐type conductivities. [ABSTRACT FROM AUTHOR]

The environmental instability and uneliminable electronic trap states in black phosphorus quantum dots (BPQDs) limit the optoelectronics and related applications of BPQDs. Here, fluorinated BPQDs (F-BPQDs) are successfully synthesized by using a facile electrochemical exfoliation and synchronous fluorination method. The F-BPQDs exhibit robust ambient stability and limited fluorination capability, showing a nonstoichiometric fluorination degree ( D F ) maximum of ≈0.68. Density functional theory calculations confirm that due to the edge etching effect of fluorine adatoms, the simulated F-BPQDs become structurally unstable when D F surpasses the limit. Furthermore, the trap states of BPQDs can be effectively eliminated via fluorination to obtain a coordination number of 3 or 5 for fluorinated and unfluorinated phosphorus atoms. The results reveal that the air-stable F-BPQDs exhibit fluorine defect-enhanced electronic tolerance, which is crucial for nanophotonics and nanoelectronics applications.

Synthetic β-peptides are potential functional mimetics of native α-proteins. A recently developed, novel, synthetic approach provides an effective route to the broad group of β-proline oligomers with alternating patterns of stereogenic centers. Conformation of the pyrrolidine ring, Z / E isomerism of β-peptide bonds, and hindered rotation of the neighboring monomers determine the spatial structure of this group of β-proline oligopeptides. Preferences in their structural organization and corresponding thermodynamic properties are determined by NMR spectroscopy, restrained molecular dynamics and quantum mechanics. The studied β-proline oligopeptides exist in dimethyl sulfoxide solution in a limited number of conformers, with compatible energy of formation and different spatial organization. In the β-proline tetrapeptide with alternating chirality of composing pyrrolidine units, one of three peptide bonds may exist in an E configuration. For the alternating β-proline pentapeptide, the presence of an E configuration for at least of one β-peptide bond is mandatory. In this case, three peptide bonds synchronously change their configurations. Larger polypeptides may only exist in the presence of several E configurations of β-peptide bonds forming a wave-like extended structure.

High-resolution vacuum ultraviolet photoabsorption measurements in the wavelength range of 115-320 nm (10.8-3.9 eV) have been performed together with comprehensive relativistic time-dependent density functional calculations (TDDFT) on the low-lying excited sates of tungsten hexacarbonyl, W(CO) 6 . The higher resolution obtained reveals previously unresolved spectral features of W(CO) 6 . The spectrum shows two higher-energy bands (in the energy ranges of 7.22-8.12 eV and 8.15-9.05 eV), one of them with clear vibrational structure, and a few lower-energy shoulders in addition to a couple of lower-energy metal-to-ligand charge-transfer (MLCT) bands reported in the literature before. Absolute photoabsorption cross sections are reported and, where possible, compared to previously published results. On the basis of this combined experimental/theoretical study the absorption spectrum of the complex has been totally re-assigned between 3.9 and 10.8 eV under the light of spin-orbit coupling (SOC) effects. The present comprehensive knowledge of the nature of the electronically excited states may be of relevance to estimate neutral dissociation cross sections of W(CO) 6 , a precursor molecule in focused electron beam induced deposition (FEBID) processes, from electron scattering measurements.

Large-area (∼cm 2 ) films of vertical heterostructures formed by alternating graphene and transition-metal dichalcogenide (TMD) alloys are obtained by wet chemical routes followed by a thermal treatment at low temperature. In particular, we synthesized stacked graphene and W x Mo 1-x S 2 alloy phases that were used as hydrogen evolution catalysts. We observed a Tafel slope of 38.7 mV dec -1 and 96 mV onset potential (at current density of 10 mA cm -2 ) when the heterostructure alloy was annealed at 300 °C. These results indicate that heterostructures formed by graphene and W 0.4 Mo 0.6 S 2 alloys are far more efficient than WS 2 and MoS 2 by at least a factor of 2, and they are superior compared to other reported TMD systems. This strategy offers a cheap and low temperature synthesis alternative able to replace Pt in the hydrogen evolution reaction (HER). Furthermore, the catalytic activity of the alloy is stable over time, i.e., the catalytic activity does not experience a significant change even after 1000 cycles. Using density functional theory calculations, we found that this enhanced hydrogen evolution in the W x Mo 1-x S 2 alloys is mainly due to the lower energy barrier created by a favorable overlap of the d-orbitals from the transition metals and the s-orbitals of H 2 ; with the lowest energy barrier occurring for the W 0.4 Mo 0.6 S 2 alloy. Thus, it is now possible to further improve the performance of the "inert" TMD basal plane via metal alloying, in addition to the previously reported strategies such as creation of point defects, vacancies and edges. The synthesis of graphene/W 0.4 Mo 0.6 S 2 produced at relatively low temperatures is scalable and could be used as an effective low cost Pt-free catalyst.

At present, metal/metal oxide composites are considered as potential oxygen reduction reaction (ORR) catalysts for energy-related applications like fuel cells. Here, we fabricated a high-activity, low Pt loading ORR electrocatalyst composed of nanoporous Pt (np-Pt) in intimate contact with lamellar (Mn,Al) 3 O 4 nanosheet (NS). In comparison to Pt/C (Johnson Matthey), the np-Pt/(Mn,Al) 3 O 4 NS catalyst shows a 11.5-fold enhancement in the mass-normalized ORR activity and much better methanol tolerance because of the metal-support interactions between np-Pt and (Mn,Al) 3 O 4 . Furthermore, the combination of electrochemical experiments with theoretical calculations verifies that the ORR on the np-Pt/(Mn,Al) 3 O 4 NS catalyst is a direct 4e - pathway in the alkaline solution. In addition, the electrocatalytic mechanisms have also been rationalized by density functional theory (DFT) calculations.

The charge transfer and photophysics in a new light-emitting cocrystal with ribbon-like morphology are revealed in-depth. These cocrystals can serve as an efficient 1D optical waveguide, and the cocrystal waveguide couplers fabricated by a probe-assisted crystal-moving technique exhibit interfacial white emission and can function as basic photonic logic gates, showing potential for future integrated photonics., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

By using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) coupled with density functional theory (DFT) calculations, we demonstrate the atomic-level imaging of cation ordering in inverse spinel Zn2SnO4 nanowires. This cation ordering was identified as 1:1 ordering of Zn(2+) and Sn(4+) at the octahedral sites of the inverse spinel crystal with microscopic symmetry transition from original cubic Fd3̅m to orthorhombic Imma group. This ordering generated a 67.8% increase in the elastic modulus and 1-2 order of magnitude lower in the electric conductivity and electron mobility compared to their bulk counterpart.