Hot electron chemistry has drawn tremendous attention from applications related to materials, energy, sensing, and catalysis. The plasmon‐induced generation of hot electrons and their transfer behavior are very important for understanding plasmonic‐enhanced applications and for achieving practically useful efficiency. From a plasmonic perspective, well‐designed plasmonic structures that can manipulate surface plasmons are able to enhance the efficiencies of hot electron‐based processes. This progress report summarizes the recent experimental and theoretical advances on the hot electron effect, emphasizing the crucial role of surface plasmons that are highly designable by using metal nanostructures. In particular, recent breakthroughs in the emerging fields of heterogeneous catalysis based on the hot electron effect are highlighted. Important design principles, mechanisms, and concepts, as well as challenges and perspectives, are illustrated and discussed.

Magnetic nanoparticle clusters (MNCs) are a class of secondary structural materials that comprise chemically defined nanoparticles assembled into clusters of defined size. Herein, MNCs are fabricated through a one-pot solvothermal reaction featuring self-limiting assembly of building blocks and the controlled reorganization process. Such growth-dissolution-regrowth fabrication mechanism overcomes some limitations of conventional solvothermal fabrication methods with regard to restricted available feature size and structural complexity, which can be extended to other oxides (as long as one can be chelated by EDTA-2Na). Based on this method, the nanoparticle size of MNCs is tuned between 6.8 and 31.2 nm at a fixed cluster diameter of 120 nm, wherein the critical size for superparamagnetic-ferromagnetic transition is estimated from 13.5 to 15.7 nm. Control over the nature and secondary structure of MNCs gives an excellent model system to understand the nanoparticle size-dependent magnetic properties of MNCs. MNCs have potential applications in many different areas, while this work evaluates their cytotoxicity and Pb(2+) adsorption capacity as initial application study.

Multicomponent nanoparticles that incorporate multiple nanocrystal domains into a single particle represent an important class of material with highly tailorable structures and properties. The controlled synthesis of multicomponent NPs with 3 or more components in the desired structure, particularly anisotropic structure, and property is, however, challenging. Here, we developed a polymer and galvanic replacement reaction-based transformative heterointerface evolution (THE) method to form and tune gold-copper-silver multimetallic anisotropic nanoparticles (MAPs) with well-defined configurations, including structural order, particle and junction geometry, giving rise to extraordinarily high tunability in the structural design, synthesis and optical property of trimetallic plasmonic nanoantenna structures. MAPs can easily, flexibly integrate multiple surface plasmon resonance (SPR) peaks and incorporate various plasmonic field localization and enhancement within one structure. Importantly, a heteronanojunction in these MAPs can be finely controlled and hence tune the SPR properties of these structures, widely covering UV, visible and near-infrared range. The development of the THE method and new findings in synthesis and property tuning of multicomponent nanostructures pave ways to the fabrication of highly tailored multicomponent nanohybrids and realization of their applications in optics, energy, catalysis and biotechnology.

One of the most heavily used methods in chemical and biological labeling, detection, and imaging is based on silver shell-based enhancement on Au nanoparticles (AuNPs) that is useful for amplifying Rayleigh scattering, colorimetric signal, surface-enhanced Raman scattering, and electrical signal, but poor structural controllability and nonspecific growth of silver shells have limited its applications, especially with respect to signal reproducibility and quantification. Here, a highly specific, well-defined Cu nanopolyhedral shell overgrowth chemistry is developed with the aid of polyethyleneimine (PEI) on AuNPs, and the use of this PEI-mediated Cu polyhedral nanoshell (CuP) chemistry is shown as a means of light-scattering signal enhancement for the development of naked-eye-based highly sensitive and quantitative detections of DNA and viruses. Remarkably, these CuPs are exclusively formed on AuNPs in a controllable manner, with no noticeable nonspecific CuP growth. The findings enable to acquire clearly visible signals without analytic instrumentation, detectable down to 8 × 10 m of DNA (anthrax sequence) and 2700 copies of viruses (noroviruses in clinical stool samples) with broad dynamic ranges on archetypal assay platforms. This new method provides a general platform in controlling Cu shell nanostructures and their optical signals, and opens up revenues for highly reliable, quantitative onsite naked-eye biodetection.

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Multiwalled carbon nanotubes (MWCNT) were homogeneously covered with a bio-functional polydopamine (PDOP) by a simple dip-coating approach in mild basic solution. Then, uniformly dispersed and highly loaded platinum nanoparticles (PtNPs) were deposited on MWCNT@PDOP by a mild reductant, and were characterized by transmission electron microscopy and x-ray photoelectron spectroscopy. Afterwards, this nanocomposite was modified on the glass carbon electrode and applied to simultaneously determine dopamine (DA) and uric acid (UA) by differential pulse voltammetry (DPV). Results showed that a linear electro-oxidation response was found for DA and UA in the range of 0.25-20 μM and 0.3-13 μM with the detection limit (S/N = 3) of 0.08 μM and 0.12 μM, respectively. In addition, the detection sensitivities for DA and UA by DPV were 1.03 μA μM(-1) and 2.09 μA μM(-1), respectively, which were much higher than those from a cyclic voltammogram. Finally, the reproducibility and stability of the nanocomposite were also evaluated, demonstrating that such MWCNT@PDOP@PtNPs can be a promising candidate for advanced electrode material in electrochemical sensing and other electrocatalytic applications.

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