Wetting sub-nanochannels via ionic hydration effect for improving charging dynamics

The ionic transport in sub-nanochannels plays a key role in energy storage,yet suffers from a high energy barrier.Wetting sub-nanochannels is crucial to accelerate ionic transport,but the introduction of water is challenging because of the hydrophobic extreme confinement.We propose wetting the channels by the exothermic hydration process of pre-intercalated ions,the effect of which varies distinctly with different ionic hydration structures and energies.Compared to the failed pre-intercalation of SO_(4)^(2-),HSO_(4)^(-) with weak hydration energy results in a marginal effect on the HOMO(Highest Occupied Molecular Orbital)level of water to avoid water splitting during the electrochemical intercalation.Meanwhile,the ability of water introduction is reserved by the initial incomplete dissociation state of HSO_(4)^(-),so the consequent exothermic reionization and hydration processes of the intercalated HSO_(4)^(-) promote the water introduction into sub-nanochannels,finally forming the stable confined water through hydrogen bonding with functional groups.The wetted channels exhibit a significantly enhanced ionic diffusion coef-ficient by~9.4 times.

Density functional theory and kinetic Monte Carlo simulation study the strong metal-support interaction of dry reforming of methane reaction over Ni based catalysts

Oxide supports modify electronic structures of supported metal nanoparticles,and then affect the catalytic activity associated with the so-called strong metal-support interaction(SMSI).We herein report the strong influence of SMSI employing Ni_(4)/α-MoC(111) and defective Ni_(4)/MgO(100) catalysts used for dry reforming of methane(DRM,CO_(2)+CH_4→2 CO+2 H_(2)) by using density functional theory(DFT) and kinetic Monte Carlo simulation(KMC).The results show that α-MoC(111) and MgO(100) surface have converse electron and structural effect for Ni_(4) cluster.The electrons transfer from a-MoC(111) surface to Ni atoms,but electrons transfer from Ni atoms to MgO(100) surface;an extensive tensile strain is greatly released in the Ni lattice by MgO,but the extensive tensile strain is introduced in the Ni lattice by α-MoC.As a result,although both catalysts show good stability,H_(2)/CO ratio on Ni_(4)/α-MoC(111) is obviously larger than that on Ni_(4)/MgO(100).The result shows that Ni/α-MoC is a good catalyst for DRM reaction comparing with Ni/MgO catalyst.

Engineering Sodium Metal Anode with Sodiophilic Bismuthide Penetration for Dendrite-Free and High-Rate Sodium-Ion Battery

Sodium(Na)metal batteries with a high volumetric energy density that can be operated at high rates are highly desirable.However,an uneven Na-ion migration in bulk Na anodes leads to localized deposition/dissolution of sodium during high-rate plating/stripping behaviors,followed by severe dendrite growth and loose stacking.Herein,we engineer the Na hybrid anode with sodiophilic Na_(3)Bi-penetration to develop the abundant phase-boundary ionic transport channels.Compared to intrinsic Na,the reduced adsorption energy and ion-diffusion barrier on Na_(3)Bi ensure even Na^(+)nucleation and rapid Na^(+)migration within the hybrid electrode,leading to uniform deposition and dissolution at high current densities.Furthermore,the bismuthide enables compact Na deposition within the sodiophilic framework during cycling,thus favoring a high volumetric capacity.Consequently,the obtained anode was endowed with a high current density(up to 5 mA∙cm^(−2)),high areal capacity(up to 5 mA∙h∙cm^(−2)),and long-term cycling stability(up to 2800 h at 2 mA∙cm^(−2)).

A DFT study on the interaction of Co with an anatase TiO_2 (001)-(1×4) surface

The substitution/adsorption structures of Co on an anatase TiO2 （001）-（1 × 4） surface are investigated using the DFT/local density approximation （LDA） method. Theoretical calculation shows that the Co ion prefers to be adsorbed on the surface of anatase TiO2. The density of states （DOS） analysis finds that the Co 3d is located mainly in the energy gap region. The Co 3d partial density of states （PDOS） indicates that there is a substantial degree of hybridization between O 2s and Co 3d in valence band （VB） regions in the substitution models. The conclusion is that the mode of substitution is more active when the catalyst is a higher-energy surface.

Facet-dependent catalytic activity of CeO_(2) toward methanol synthesis from methane

The relationship between CeO_(2) morphology(nano rods,NR;nano cubes,NC;nano octahedra,NO) and methanol synthesis from methane at low reaction temperature was studied by using density functional theory(DFT) and experiments.CeO_(2)(110) displays the lowest energy barriers among CeO_(2)(100),CeO_(2)(111) and CeO_(2)(110) surfaces due to the strongest hybridization between O 2p orbital of OH and Ce4f orbital.As a result,CeO_(2)-NR has the highest methanol yield(1.52 μmol/gcat) compared with CeO_(2)-NC(0.60 μmol/gcat)and CeO_(2)-NO(0.66 μmol/gcat) at 453 K and 101325 Pa.These results show that methanol synthesis from methane at low reaction temperature on CeO_(2)is a morphology sensitive reaction.

New strategy for production of primary alcohols from aliphatic olefins by tandem cross-metathesis/hydrogenation

Primary alcohols are widely used in industry as solvents and precursors of detergents.The classic methods for hydration of terminal alkenes always produce the Markovnikov products.Herein,we reported a reliable approach to produce primary alcohols from terminal alkenes combining with biomass-derived allyl alcohol by tandem cross-metathesis/hydrogenation.A series of primary alcohol with different chain lengths was successfully produced in high yields(ca.90%).Computational studies revealed that self-metathesis and hydrogenation of substrates are accessible but much slower than crossmetathesis.This new methodology represents a unique alternative to primary alcohols from terminal alkenes.