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A unique architecture (Bi@NS-C) was rationally designed to address the internal mechanical stress, pulverization and shedding issues of the material. This work provides a strategy in alloying materials for boosting reversible and stable sodium/potassium-ion storage.

Bimetallic nanoparticles (NPs) usually exhibit some novel properties due to the synergistic effects of the two distinct metals, which is expected to play an important role in the field of gas sensing. PdPt bimetal NPs with Pd-rich shell and Pt-rich core were successfully synthesized and used to modify SnO2nanosheets. The 1P-PdPt/SnO2-A sensor obtained by self-assemblies of PdPt NPs exhibited temperature-dependent dual selectivity to CO at 100 °C and CH4at 320 °C. Furthermore, the sensor possessed good long term stability and antihumidity interference. The activation energy of adsorption for CO and CH4were estimated by the temperature-dependent response process modeled using Langmuir adsorption kinetics, which proved that the lower activation energy of adsorption corresponded to better sensing performance. The gas-sensing mechanism based on the diffusion depth of the tested gas in the sensing layer was discussed. The dramatically improved sensing performance could be ascribed to the high catalytic activity of PdPt bimetal, the electron sensitization of PdO, and Schottky barrier-type junctions at the interface between SnO2and PdPt NPs. Our present results demonstrate that bimetal NPs with special structure and components can significantly improve the gas-sensing performance of metal oxide semiconductor and the obtained sensor has great potential in monitoring coal mine gas.

A first principles approach based on adiabatic substitution is proposed to evaluate the redox potentials of a series of solute cations Mm + (Cu+, Au+, Tl+, Nd2+, Sc3+, Y3+, Ce3+, Pr3+, Nd3+, Gd3+, Tb3+, U3+, Pu3+, Np3+ and Am3+) in molten LiCl-KCl eutectic solvent at 723 K. A thermodynamic cycle is designed by adiabatic substitution of cation and neutral atom in molten salt with reference cation and reference neutral atom (Ag+ and Ag0 for monovalent cations, Ni2+ and Ni0 for divalent cation, and La3+ and La0 for trivalent cations) and vice versa. The redox potentials of these cations are evaluated relative to theAg+(sol)|AgCl(s)|Ag(s), Ni2 +(sol)|NiCl2(s)|Ni(s) and La3 +(sol)|LaCl3(s)|La(s) reference electrodes, respectively. Good agreements with experimental values are obtained with maximum absolute error of 0.354 V and standard deviation of 0.226 V. In addition, the first principles molecular dynamics (FPMD) is applied to the study of solvation structures of MClm in molten LiCl-KCl eutectic in terms of radial distribution functions and partial static structure factors in satisfactory agreement with X-ray and neutron diffraction characterizations. It is revealed that the solute cation affects significantly the intermediate-range order of Li+-Li+ but slightly of Cl[?]-Cl[?] and K+-K+.

Molten salts and molten salt mixtures (will be referred as molten salts for convenience) are important heat storage media and heat transfer fluids for concentrated solar power plants and molten salt reactors. Besides the heat capacity, the thermal conductivity, and the thermal and chemical stability, the viscosity is also widely studied by experimental measurements and theoretical predictions because of the importance in engineering applications. In this work, the experimental viscosities of molten salts are compiled from literatures, and a novel empirical equation is proposed for the prediction of the temperature dependence of viscosity of molten salts. This novel empirical equation extends the Arrhenius equation with three empirical parameters and performs better than the Arrhenius equation for the applications to fluorides, chlorides, nitrates, and carbonates. Finally, its physical basis is discussed and the empirical parameters are recommended for molten salts with experimental viscosity being reported in literatures.

Electrorefining is an important unit operation for the pyroprocessing of used nuclear fuel; however, the uncontrolled growth of uranium dendrites on the cathode is hindering its engineering application. In this study, the phase-field modelling is applied to the study of the growth of uranium dendrites using the finite element method, and the fractal dimension and the perimeter-to-area ratio are employed to classify quantitatively the morphologies of uranium dendrites. It is shown that uranium dendrites can form sprout-like, fishbone-like, and tree-like morphologies, and the effects of anisotropic strength, symmetry index, overpotential, and temperature to the morphologies of uranium dendrites are discussed. It is concluded that the diffusion of uranium cations (diffusion rate-controlling) in molten salt and the electrode kinetics (kinetic rate-controlling) are the two rate-controlling steps for the electrodeposition of uranium, and the diffusion rate-controlling mechanism is responsible for the growth of complicated dendritic morphologies.

Hydrogen is regarded as a future sustainable and clean energy carrier. Formic acid is a safe and sustainable hydrogen storage medium with many advantages, including high hydrogen content, nontoxicity, and low cost. In this work, a series of highly active catalysts for hydrogen production from formic acid are successfully synthesized by controllably depositing Pd onto Ag nanoplates with different Ag nanofacets, such as Ag{111}, Ag{100}, and the nanofacet on hexagonal close packing Ag crystal (Ag{hcp}). Then, the Pd–Ag nanoplate catalysts are supported on Vulcan XC-72 carbon black to prevent the aggregation of the catalysts. The research reveals that the high activity is attributed to the formation of Pd–Ag alloy nanofacets, such as Pd–Ag{111}, Pd–Ag{100}, and Pd–Ag{hcp}. The activity order of these Pd-decorated Ag nanofacets is Pd–Ag{hcp} > Pd–Ag{111} > Pd–Ag{100}. Particularly, the activity of Pd–Ag{hcp} is up to an extremely high value, i.e., TOF{hcp}= 19 000 ± 1630 h–1at 90 °C (lower limit value), which is more than 800 times higher than our previous quasi-spherical Pd–Ag alloy nanocatalyst. The initial activity of Pd–Ag{hcp} even reaches (3.13 ± 0.19) × 106h–1at 90 °C. This research not only presents highly active catalysts for hydrogen generation but also shows that the facet on the hcp Ag crystal can act as a potentially highly active catalyst.

To obtain suitable data for the pyrometallurgical post-processing in the fusion-fission hybrid reactor, the structure and transport characteristics of molten LiCl-KCl mixture containing UCl3were studied by molecular dynamics simulation. The radial distribution functions, densities, and self-diffusion coefficients were investigated at various molar fractions of UCl3. In the molten LiCl-KCl-UCl3salt mixture, the first peak for gU-Cl(r) was located at 0.266 nm, which was slightly left-shifted than the X-ray diffraction data, i.e., 0.285 nm for pure molten UCl3. The preexponential factors for U3+decreased from 46.2×10−5cm2/s to 32.2×10−5cm2/s as the molar fraction of U3+increased from 0.005 to 0.05.

Electrorefining is an important unit operation for the pyroprocessing of spent nuclear fuel; however, the uncontrolled growth of uranium dendrites traps molten salt into the deposited uranium, increases the short-circuit risk, decreases the current efficiency, and thus hinders the engineering application of the electrorefining technology. In this study, the finite element method is applied to the study of the electrorefining dynamics subjected to convection, diffusion, electromigration, and electrode reaction. The velocity field, concentration field, electric field, and flux density field are evaluated. The local current density on the cathode is evaluated under different overall current densities, overpotentials, cathodic shapes and positions for the evaluation of dendritic growth. Finally, it is concluded that the uranium will be deposited priorly onto the cathode tip and the frontside of the cathode facing the anode, the position of the electrode and the shape of the cathode tip will not have significant influence to the priority of deposition, and a glass insulated tip can effectively improve the uneven growth of uranium dendrites on the cathode surface as proposed by Srihari et al. (Sep. Sci. Technol. 51, 1397).

An aspartic acid-functionalized water-soluble perylene bisimide, N,N′-di(2-succinic acid)-perylene-3,4,9,10-tetracarboxylic bisimide (PASP) was synthesized and characterized. It has absorbance maximum A0–0and A0–1at 527 and 498 nm (ε ≈ 1.7 × 104L cm–1mol–1) respectively in pH 7.20 HEPES buffer. Two quasi-reversible redox processes with E1/2at −0.17 and −0.71 V (vs Ag/AgCl) respectively in pH 7–12.5 aqueous solutions. PASP can react with Na2S in pure aqueous solution to form monoanion radical and dianion species consecutively. PASP–•has EPR signal with g= 1.998 in aqueous solution, whereas PASP2-is EPR silent. The monoanion radical formation is a first-order reaction with k= 8.9 × 10–2s–1. Dianion species formation is a zero-order reaction and the rate constant is 4.3 × 10–8mol L–1s–1. The presence of H2O2greatly increases the radical formation rate constant. PASP as a two-electron transfer reagent is expected to be used in the water photolysis.

Quantitative Structure–Property Relationship QSPR model was developed to correlate structures of aromatic compounds with their noctanol–water partition coefficient logKow. The 68 molecular descriptors derived solely from the structures of the aromatic compounds were calculated using Gaussian 03, HyperChem 7.5, and TSAR V3.3. The descriptors were screened by the minimum Redundancy Maximum Relevance mRMRGenetic Algorithm GASupport Vector Regression SVR method. The parameters of the SVR model were optimized using the fivefold crossvalidation method. The QSPR model was developed from a training set consisting of 300 compounds using the SVR method with a good determination coefficient R2=0.85. The QSPR model was then tested using an external test set consisting of 50 compounds with satisfactory external predictive ability q2=0.84. The results show that mRMRGASVR feature selection method and SVR method can be used to model logKowfor a diverse set of aromatic compounds and could be promising tools in the field of QSPR research.

We study the electrical characteristics of a group of glycine oligopeptides (1-, 3-, 6-, and 9-mers) molecules attached to gold nanoelectrodes using a combined density functional theoryGreen's function approach. Our procedure considers the applied voltage through the molecule and contacts, recalculates self-consistently the molecular orbitals, Hamiltonian and overlap matrices at each applied voltage, and uses these results to estimate the current−voltage characteristics such that the chemistry of the molecule is fully considered when including the effect of the nanoelectrodes. Our results show that oligoglycines can be used to tailor specific properties for the fabrication of molecular devices and the characteristics may be strongly affected by the few contact atoms addressing the molecule. Oligoglycines show transport behaviors that go from ohmic conductance to Schottky barriers as the length of the oligomers and conformation of the electrode atoms vary.

Gas–liquid–solid (G–L–S) three-phase slug flow provides an efficient pathway to utilize solid catalysts in continuous flow and was adopted in the mesoporous graphite carbon nitride (mpg-C3N4)-catalyzed photoinduced electron/energy transfer reversible addition–fragmentation chain transfer (PET-RAFT) polymerization of methyl methacrylate (MMA) in this work. Kinetic studies and chain extension experiments illustrated the realization of reversible deactivation radical polymerization (RDRP) and the “easy to scale up” advantage of a continuous-flow reactor as compared to its batch counterpart. The light intensity played an important role on the PET-RAFT polymerization. An increasing amount of photocatalyst favored the monomer conversion within a limited range due to higher light blockage, and the monomer conversion reached a stable level at a lower catalyst concentration when higher light power was applied. When compared with fully continuous flow, the G–L–S slug flow was beneficial to the PET-RAFT polymerization due to the intensified swirling strength and narrower velocity field. Decreasing the gas-to-slurry ratio also led to narrower velocity distribution, which favored the polymerization as well. Moreover, the polymerization rates remained stable in multiple recycles, demonstrating that the present G–L–S slug flow was a reliable and easy processing approach for utilizing the solid catalyst.

A calculation procedure of redox potential with respect to the standard hydrogen electrode (SHE) in ionic liquid of 3-(2-carboxyethyl)?1-methyl-1H-imidazol-3-ium bis((trifluoromethyl)sulfonyl)amide () is developed based on density functional theory (DFT) and Nernst equation in terms of Gibbs free energy. The Gibbs free energy is evaluated at the theory level of B3LYP/6-311++G(d,p)/SDD and the solvation effect is corrected using conductor-like polarizable continuum model (CPCM). The solvation Gibbs free energy of proton in ionic liquid is evaluated using hybrid solvent models of explicit solvent molecules and implicit solvent model of CPCM. Our calculated redox potentials agree satisfactorily with experimental observations reported in literatures with maximum absolute of 0.237 V.

A first principles approach based on adiabatic substitution is proposed to evaluate the redox potentials of a series of solute cations Mm+(Cu+, Au+, Tl+, Nd2+, Sc3+, Y3+, Ce3+, Pr3+, Nd3+, Gd3+, Tb3+, U3+, Pu3+, Np3+and Am3+) in molten LiCl-KCl eutectic solvent at 723 K. A thermodynamic cycle is designed by adiabatic substitution of cation and neutral atom in molten salt with reference cation and reference neutral atom (Ag+and Ag0for monovalent cations, Ni2+and Ni0for divalent cation, and La3+and La0for trivalent cations) and vice versa. The redox potentials of these cations are evaluated relative to theAg+(sol)|AgCl(s)|Ag(s), Ni2 +(sol)|NiCl2(s)|Ni(s) and La3 +(sol)|LaCl3(s)|La(s) reference electrodes, respectively. Good agreements with experimental values are obtained with maximum absolute error of 0.354 V and standard deviation of 0.226 V. In addition, the first principles molecular dynamics (FPMD) is applied to the study of solvation structures of MClmin molten LiCl-KCl eutectic in terms of radial distribution functions and partial static structure factors in satisfactory agreement with X-ray and neutron diffraction characterizations. It is revealed that the solute cation affects significantly the intermediate-range order of Li+–Li+but slightly of Cl−–Cl−and K+–K+.