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It is a highly relevant topic concerning how to improve the electrochemical performance of anode materials for the next generation lithium-ion batteries (LIBs). Herein, for the first time, we report a facile and controllable approach to modify MoS2 nanosheets, a typical 2D material, as an anode material for advanced LIBs via oxygen plasma engineering. An oxygen plasma treatment not only generates vacancies/defects but also incorporates heteroatom doping to form Mo–O–C bonds. This unique hybrid specialty enables the oxygen-plasma-treated MoS2 to achieve superior electrochemical performance with high reversible capacities, a long-term cycle life, and good rate capabilities. The plasma-assisted modification is believed to be applicable for other 2D materials as an efficient anode for energy storages.

To reduce the conservativeness of robust optimization-based unit commitment methods, an uncertainty set is usually prespecified with respect to the distributions of uncertain renewable resources, i.e., wind power. However, since the law of large numbers does not always work in practice, the obtained probability distribution may be unreliable. In this paper, a data-driven adaptive robust optimization method for the unit commitment of bulk power systems with high-level wind power integration is proposed. Different from the conventional robust unit commitment methods, the distributional uncertainty of wind power is well respected in the proposed approach. An imprecise-Dirichlet-model-based method is developed to construct the ambiguity set of wind power, which incorporates all possible probability distributions confirmed by historical data. The set can dynamically change with the data, i.e., the more valid data we have, the smaller the ambiguity set will become. With respect to the bounds of the ambiguity set, a polyhedron uncertainty set of wind power is constructed. By tuning the parameters of the uncertainty set, a balance between operational efficiency and risk can be achieved. An adaptive, robust unit commitment model is constructed based on the uncertainty set. By using the duality principle and big-M method, the formulations are converted into a mixed integer linear programming problem and solved using a column and constraint generation algorithm. Case studies on two benchmark systems illustrate the effectiveness and efficiency of the proposed method.

The interlayer interactions in nonpolar graphite and other B C N layered materials involving polar covalent bonds (h-BN, g-C3N4, graphite-like BC3 and BC2N) have been investigated by dispersion-corrected density functional calculations. Lattice parameters, bulk moduli and interlayer binding energies of these layered materials have been calculated using different dispersion correction schemes for comparison. Charge density difference plots have also been presented to elucidate the charge transfer behaviors along the nonpolar/polar covalent bonds as well as in the interlayer region. At first, graphite and h-BN were examined as benchmarks; the former contains planar graphene layers regardless of the interlayer binding, while the monolayers in the latter exhibit an asymmetric charge distribution along the B N polar bonds, leading to a slightly puckered feature induced by the interlayer interaction. Similar geometric deviations have also been observed in other layered structures involving C N and/or B C polar bonds, but with distinct characteristics directly related to their specific interlayer stacking situations. By contrast, all of the isolated monolayers free from interlayer binding show a pristine planar feature in despite of the polar covalent bonds involved. Our theoretical findings further address the necessity of considering the electron-density variations induced by specific bonding environments in polar B C N layered materials, which can be properly described by the Tkatchenko-Scheffler correction.

A large number of literatures have investigated the selective photocatalytic reaction of 4-aminothiophenol (PATP) to p,p'-dimercaptoazobenzene (DMAB). Most of them mainly study the contribution of substrate, excitation wavelength, exposure time, pH and added cations to plasmon-assisted surface catalytic reactions. However, we mainly study focuses on the effects of solvents on the dimerization of PATP to DMAB under the action of Ag nanoparticles (NPs). In experiments, a variety of diols was selected as solvents for the probe molecule PATP, and power-dependent SERS spectra were obtained at an excitation wavelength of 532 nm. From the laser-dependent SERS spectrum, we found that the characteristic peak enhancement effect of the product DMAB in different solvents is significantly different. That is, different solvents could regulate the rate at which DMAB is produced from PATP. Based on the experimental results, we further explored how different diol solvents regulate the response of PATP to DMAB. Our conclusion is that the solvent in the system can quickly capture the hot electrons generated by the decay of the plasmon, so that the remaining holes can oxidize PATP to form DMAB. The ability to trap hot electrons is different due to the difference in the position of the functional groups in the solvent, so that the photocatalytic reaction rate of the hole-oxidized PATP is different. The ability to capture electrons varies depending on the position of the functional groups in the solvent, so the oxidation rate of the photocatalytic reaction is also different. This work not only deepens our understanding of the mechanism of hole-driven surface catalysis oxidation reaction, but also provides a convenient method for regulating the rate of catalytic oxidation.

Turbostratic carbon nitride was prepared by the pyrolysis of melamine and then treated with a pulse discharge for different times. It is found that after this high-temperature short-time treatment, the structures of the products have changed while the high nitrogen content has been effectively maintained. The obtained product was characterized by X-ray diffraction and infrared spectroscopy. The composition was measured by an element analyzer. An orthorhombic CN x phase has been obtained, identified by transmission electron microscopy coupled with selected area electron diffraction. High-resolution transmission electron microscopy revealed that the product has some nanocrystals having a fringe spacing of approximately 0.32 nm, which embedded in a turbostratic matrix.