No abstract

High-dimensionally structured Mo–Fe oxide (HDS-MoFeO) was synthesized through an assembly of structural units supplied from Keplerate-type polyoxometalate, {Mo72Fe30}, under an appropriate hydrothermal condition. HDS-MoFeO showed excellent catalytic activity for the selective oxidation of methanol with slightly lower selectivity for formaldehyde than that of a conventional Mo–Fe oxide catalyst.

The effects of the addition of crystalline Mo 3 VO x oxides (MoVO) seeds on an assembly of pentagonal [Mo 6 O 21 ] 6− building units with Mo and V octahedra for forming MoVO were investigated. In the absence of the seeds, the crystal phase of formed MoVO depended on the pH of the preparative solution, while the crystal phase of the formed MoVO was decided by the phase of the MoVO seeds used irrespective of the pH. Interestingly, MoVO were formed even in the pH condition where no crystals were formed in the absence of the seeds. It was shown by X-ray diffraction, scanning transmission electron microscopy−energy-dispersive X-ray spectroscopy, and scanning electron microscopy that MoVO crystals were grown from the crosssection of the rod-shaped crystals of the MoVO seeds.

The authors present metasurface‐inspired maintenance‐free Internet of things (IoT) tags that can be characterised not only by frequency‐domain profiles but also by time‐domain profiles. In particular, time‐domain characterisation is made possible by implementing the waveform‐selective mechanisms of recently developed circuit‐based metasurfaces that behave differently, even at the same frequency, in accordance with the pulse duration of the incident wave. The proposed designs are numerically and experimentally validated and potentially contribute to accommodating an increasing number of IoT tags within a single wireless network while reducing maintenance effort.