In this contribution, we present a high-throughput method for the synthesis of titanium nitride nanoparticles. The technique, based on a continuous-flow nonthermal plasma process, leads to the formation of free-standing titanium nitride particles with crystalline structures and below 10 nm in size. Extinction measurements of the as-synthesized particles show a clear plasmonic resonance in the near-infrared region, with a peak plasmon position varying between 800 and 1000 nm. We have found that the composition can be controllably tuned by modifying the process parameters and that the particle optical properties are strongly dependent upon composition. XPS and STEM/EDS analyses suggest that nitrogen-poor particles are more susceptible to oxidation, and the extinction spectra show a decrease and a red-shift in plasmon peak position as the degree of oxidation increases. The role of oxidation is confirmed by realtime, time-dependent density functional tight binding (RT-TDDFTB) calculations, which also predict a decrease in the localized surface plasmon resonance energy when a single monolayer of oxygen is added to the surface of a titanium nitride nanocrystal. This study highlights the opportunity and challenges presented by this material system. Understanding the processing-properties relationships for alternative plasmonic materials such as titanium nitride is essential for their successful use in biomedical, photocatalytic, and optoelectronic applications.

We report colloidal routes to synthesize silicon@carbon composites for the first time. Surface‐functionalized Si nanoparticles (SiNPs) dissolved in styrene and hexadecane are used as the dispersed phase in oil‐in‐water emulsions, from which yolk–shell and dual‐shell hollow SiNPs@C composites are produced via polymerization and subsequent carbonization. As anode materials for Li‐ion batteries, the SiNPs@C composites demonstrate excellent cycling stability and rate performance, which is ascribed to the uniform distribution of SiNPs within the carbon hosts. The Li‐ion anodes composed of 46 wt % of dual‐shell SiNPs@C, 46 wt % of graphite, 5 wt % of acetylene black, and 3 wt % of carboxymethyl cellulose with an areal loading higher than 3 mg cm−2 achieve an overall specific capacity higher than 600 mAh g−1, which is an improvement of more than 100 % compared to the pure graphite anode. These new colloidal routes present a promising general method to produce viable Si–C composites for Li‐ion batteries.

Titanium nitride (TiN) offers advantages compared to standardly used plasmonic materials such as gold and silver in terms of thermal stability, cost, and sustainability. While gold and silver nanostructures have played an important role in the rapidly growing field of plasmonic catalysis, the potential of TiN in this application is still underexplored. Here we provide evidence of plasmon-driven chemical activity in TiN by using the photoreduction of platinum ions under visible−near-infrared (vis−NIR) illumination as probe reaction. An aqueous solution of TiN, methanol, and chloroplatinic acid (H 2 PtCl 6 ) was exposed to vis−NIR radiation (600−900 nm). Scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) show nanostructures composed of ∼2 nm metallic platinum clusters decorating ∼10 nm TiN nanoparticles, confirming the plasmon-driven reduction of the Pt 4+ ions to their metallic state. At the same time, the evolution of CO 2 resulting from the photooxidation of methanol is monitored via gas chromatography. The molar Pt deposition-to-CO 2 evolution ratio is in good agreement with the theoretical expectation based on the redox reaction charge balance. We have found that both Pt deposition and CO 2 evolution are self-limiting. We attribute this to the increasing plasmon dephasing rate during the photoreduction process, likely due to the high optical losses of Pt in the vis−NIR region. In addition, density functional theory (DFT) simulations of a Pt(111)−TiN(111) junction suggest the existence of an energy barrier limiting electron transfer. This work confirms that plasmonic TiN nanoparticles can use visible light to drive photochemical reactions and highlights the potential of TiN as a cost-effective alternative to gold and silver.

Nickel (Ni) nanoparticles have been synthesized from the dissociation of nickelocene (Ni(Cp)2) in an argon‐hydrogen (Ar‐H2) low pressure continuous‐flow non‐thermal plasma. The influence of process parameters on the synthesized Ni nanomaterial structure, size, size‐dispersion, and carbon content has been characterized by EDS and TEM analysis. The role of hydrogen dilution and plasma input power on material throughput is carefully discussed. These data, in combination with the prediction of the electron affinity and ionization potential of Ni(Cp)2 by DFT calculations, supports the hypothesis that the material loss‐mechanism to the reactor walls is due to the inherent ambipolar diffusion present in this synthesis technique. This study suggests that precursors should be screened with care when attempting to produce nanoparticle via a low pressure, continuous flow plasma reactor.

We discuss the synthesis and properties of nanoparticles and thin films for refractory plasmonic applications. The approach focuses on titanium nitride (TiN), which overcomes the limitations of more common plasmonic materials like silver and gold with respect to temperature stability. Freestanding TiN-based nanoparticles are produced in two serially connected plasma reactors, where TiN nanocrystals are nucleated in a first plasma stage, then aerodynamically dragged in a second stage, and conformally coated with a silicon nitride layer. An in-depth comparison between bare and coated TiN nanoparticles is presented in terms of the structural, chemical, and optical properties. Coating of the titanium nitride core reduces its oxidation upon exposure to air, drastically improving the plasmonic response. Thin films realized using the core–shell structure show practically no change in reflectivity, even when the thin films are heated to 900 °C in an inert atmosphere. This study introduces a simple surface passivation scheme that enhances the functionality of the material, providing further confirmation of the potential of nitride-based plasmonic materials as high-quality refractory optical compounds for a broad range of applications.