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The lattice strain effect in Pd–Ni core–shell nanocubes on the selectivity of urea electrolysis is elucidated, which can facilitate catalyst design for efficient urea waste treatment and concomitant cathodic hydrogen production or CO2 reduction.

Plasmonic nanoparticles show highly sensitive optical properties upon local dielectric environment changes. Hybridisation of plasmonic nanoparticles with active polymeric materials can allow stimuli-responsive and multiplex sensing over conventional monotonic sensing capacity. Such heterogeneous adlayers around the plasmonic core component, however, are likely to perturb the local refractive index in the nanometre regime and lead to uncertainty in its intrinsic sensitivity. Herein we prepare a series of polystyrene-grafted polyhedral gold nanoparticles, cubic and concave cubic cores, with different edge lengths and polymer thicknesses with precise synthesis control. Their localised surface plasmon resonance (LSPR) spectral changes are monitored to understand the effect of core morphological details in the interplay of nanoscale polymeric shells. Quantitative image analysis of changes in the core and shell shape contours and finite-difference time-domain simulations of the corresponding LSPR spectra and electric field distributions reveal that the magnitude of the LSPR spectral shift is closely dependent on the core morphology, polymer shell thickness and electric field intensity. We also demonstrate that the polystyrene-grafted gold concave cube displays higher sensitivity for nanoscale refractive index change in the polymer shell than the polystyrene-grafted gold cube at different temperatures. Our systematic investigation will help design polymer-composited plasmonic nanosensors for desirable applications.

Core-shell hybrid nanomaterials have shown new properties and functions that are not attainable by their single counterparts. Nanoscale confinement effect by porous inorganic shells in the hybrid nanostructures plays an important role for chemical transformation of the core nanoparticles. However, metal-organic frameworks (MOFs) have been rarely applied for understanding mechanical insight into such nanoscale phenomena in confinement, although MOFs would provide a variety of properties for the confining environment than other inorganic shells such as silica and zeolite. Here, we examine chemical transformation of a gold nanorod core enclosed by a zeolitic imidazolate framework (ZIF) through chemical etching and regrowth, followed by quantitative analysis in the core dimension and curvature. We find the nanorod core shows template-effective behavior in its morphological transformation. In the etching event, the nanorod core is spherically carved from its tips. The regrowth on the spherically etched core inside the ZIF gives rise to formation of a raspberry-like branched nanostructure in contrast to the growth of an octahedral shape in bulk condition. We attribute the shell-directed regrowth to void space generated at the interfaces between the etched core and the ZIF shell, intercrystalline gaps in multi-domain ZIF shells, and local structural deformation from the acidic reaction conditions.

Ammonia has emerged as a potential working fluid in adsorption heat pumps (AHPs) for clean energy conversion. It would be necessary to develop an efficient adsorbent with high-density ammonia uptake under high gas pressures in the low-temperature range for waste heat. Herein, a porous nanocomposite with MIL-101(Cr)-NH

Various nanoparticle surface layers allow unique functionalities. We developed a coating method with tetracyanoquinodimethane that forms solid layers through π stacking on gold nanorod surfaces. Its reaction mechanism was investigated with reaction time, aging time and surfactant concentration. Our method could be generalizable to different nanoparticle shapes and crystal facets.