Ultrafast Mechanochemical Synthesis of Plasmonic Transition Metal Nitride Nanoparticles

Refractory plasmonic materials, such as transition metal nitrides (TMN) and carbides (TMC) have shown the potential to replace more expensive or oxidatively unstable materials composed of gold, silver, aluminum and copper. The synthesis of TMN nanoparticles typically relies on high-temperature (>800 °C) nitridation of metal halides or oxides ranging from hours to even days. These methods are slow and consume significant amounts of energy. Herein, a rapid, room temperature mechanochemical method is presented showing effective formation of plasmonic group 4 TMN nanoparticles in as little as 60 seconds of grinding. Using this method, both mono-(TiN, ZrN, and HfN) and mixed-metal nitrides (ZrxHf1-xN, 0<x<1) can be achieved. The particles were analyzed using powder X-ray diffraction, X-ray photoelectron spectroscopy, electron microscopy, and absorbance spectroscopy. The effect of nitride source, milling time, and milling frequency on the product formation, particle size, crystallinity, and localized surface plasmon resonance were studied.