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Graphical abstract Abstract The NiFe-layered double hydroxide (LDH) nanosheets were decorated on the surface of doped BiVO 4 to structure an integrating photoanode for improving solar photoelectrochemical (PEC) water splitting efficiency, which is a dynamic research topic to solve the energy crisis and remit environmental pollution caused by fossil fuel combustion. The fabricated photoanode exhibits rapid response to visible light, enhances photocurrent density and shows significant cathodic shift compared to BiVO 4. Moreover, the measured incident photon-to-current efficiency (IPCE) of the photoanode is comparable to that reported in the literature. The amount of evolution oxygen was measured and the faradaic efficiency produced oxygen was also obtained by comparing the theoretical calculation value. The enhancement is attributed to the increase of the carrier density, the effective separation of photogenerated electron-hole and consuming of the photogenerated holes accumulated at the electrode surface, which has been confirmed by electrochemical impedance spectra (EIS) and the intensity modulated photocurrent spectra (IMPS). The work may offer a promising method for designing a high efficiency and low-cost photoanode. [ABSTRACT FROM AUTHOR]

Abstract: The static and dynamic instabilities of a torsional MEMS/NEMS actuator caused by capillary effects are studied, respectively. An instability number, η, is defined, and the critical gap distance, , between the mainplate and the substrate is derived. According to the values of η and g, the instability criteria of the actuator are presented. The dimensionless motion equation of the MEMS/NEMS torsional actuator is derived when it makes nonlinear oscillation under capillary force. The qualitative analysis of the nonlinear equation is made, and the phase portraits are presented on the phase plane. In addition, the bifurcation phenomena in the system are also analyzed. [Copyright &y& Elsevier]

The FHTiNs cathode combines the dual effects of chemical adsorption and physical restriction. It reduces the dissolution of polysulfides and promotes the transformation process of polysulfides. Finally, It realizes the result of inhibiting shuttle effect and has good application potential. [Display omitted] Lithium-sulfur battery(LSB)'s commercial manufacturing has been mainly retarded by the "shuttle effect" and low electrical conductivity of polysulfides (LiPSs). Designing a cathode with hollow and hierarchically porous structures was expected to solve the above problems. Herein, a kind of TiN particles with the hierarchical hollow double-shelled structures was synthesized and applied to cathodes of LSB. The Fig-like hollow TiO 2 particles (FHTiO 2 s) were firstly synthesized by the hard-template method. Subsequently, the Fig-like hierarchical hollow double-shelled TiN particles (FHTiNs) were synthesized by the template-free sequential transformation and separation approach (STSA). It was verified that the heating temperature and time were key parameters. Special Fig-like double-shell hollow structures could greatly increase the loading of S, and the excellent initial capacity of FHTiNs cathodes was up to 1159 mAh/g. On the one hand, the Fig-like framework in internal cavity and double-shell structures could promote the ultrahigh specific surface area, and the adsorption to LiPSs was improved by increasing active sites; On the other hand, the shuttle effect of LiPSs was weakened by the fig-like framework and double-shell structures, which slowed down the massive dissolution of sulfur in the electrolyte. As a result, the pleasant rate performance of FHTiNs cathodes was up to 400 mAh/g at 5C. This novel structures and synthesis method provided a new strategy for the designing of LSB cathodes. [ABSTRACT FROM AUTHOR]

Abstract: Among various coating processes, slot die coating belongs to a class of pre-metered coating, in which the coating film thickness can be predetermined. In the past, most research works on slot die coating have focused mainly on polymer solutions; very little information is available using suspensions as coating fluids. In this study, the effect of adding TiO2 and SiO2 in aqueous polyvinyl alcohol (PVA) solutions on slot die coating is investigated. It was found that the stable coating window was enlarged with the addition of particles, and its size increased with solids concentration. This is due to the strong interaction between polymer and particles, resulting in a higher viscosity and surface tension. As a result, the upstream coating bead is more stable and the maximum coating speed is extended to a high value, hence the coating window becomes larger. Although both viscosity and surface tension appear to contribute to the stability of coating flow, the effect of surface tension is more dominant. The surface tension of a suspension with porous particles was higher than one with hard solid particles. Consequently, the coating window obtained with the former was significantly larger than the latter. Flow visualization revealed that under the same operating conditions, the upstream dynamic contact angle for the suspension was smaller than for the aqueous polymer solution. This observation could be related to the stability of the upstream coating bead, and hence the coating window. The experimental flow fields were verified numerically with the aid of a numerical simulation package (Flow-3D). [Copyright &y& Elsevier]