1:15 PM - EL06.07.05
All-Gas Phase Plasma Synthesis of Plasmonic Zirconium Nitride for Advanced Photochemistry Applications
Chris Rudnicki1,Alejandro Alvarez1,Stephen Exarhos1,Carla Berroscope Rodriguez1,Lorenzo Mangolini1
University of California, Riverside1
Plasmonic nanomaterials interact strongly with light, and as a consequence there are of great interest in a broad variety of fields, such as photocatalysis, photochemistry, biophotonics, sensing, and wave-guiding. We present a novel technique for the synthesis of plasmonic zirconium nitride (ZrN) nanoparticles using a scalable non-thermal plasma process.1 Cost, production concerns and most importantly thermal and chemical stability motivate the search for alternative plasmonic materials to gold and silver2, like Group IV transition metal-nitrides3 such as TiN4 and the relatively unexplored ZrN. Our ZrN nanoparticles display a plasmonic peak around 620 nm and from XRD and TEM we infer the crystallinity of the particles to be a cubic rock salt structure and a tunable size distribution below 10 nm. An attractive application of these plasmonic particles is the reduction of metals like platinum and chromium (VI) species in water which are extremely toxic.5 Here we have provided evidence of plasmon-driven photocatalytic activity within visible wavelengths to reduce platinum ions in solution.6 An aqueous solution of ZrN, methanol, and chloroplatinic acid (H2PtCl6) was illuminated using a monochromator to spectrally select wavelengths in the visible regime. Energy dispersive X-ray spectroscopy (EDS) was then used to determine the ratio of reduced platinum to zirconium at a given wavelength. A similar method was used to reduce Chromium (VI), a carcinogen commonly found in water, except we use the diphenyl carbazide method to determine the amount of Chromium (VI) in solution before and after exposing it to light. We then spectrally select visible wavelengths to compare the quantum yields of Chromium (VI) reduction between our synthesized ZrN and commonly used TiO2 nanoparticles. We are able to achieve a quantum yield of up to 1.50% reducing Chromium (VI) to Chromium (III) using visible wavelengths, providing convincing evidence of photocatalytic response in this class of alternative plasmonic materials.
 Stephen Exarhos, Alejandro Alvarez-Barragan, Ece Aytan, Alexander A. Balandin, and Lorenzo Mangolini, Plasmonic Core−Shell Zirconium Nitride− Silicon Oxynitride Nanoparticles, ACS Energy Letters, 3 (10), 2349-2356, 2018.
 Naik, G. V., Shalaev, V. M., & Boltasseva, A. Alternative plasmonic materials: Beyond gold and silver. Advanced Materials, 25(24), 3264–3294, 2013.
 Guler, U., Shalaev, V. M., & Boltasseva, A. Nanoparticle plasmonics : going practical with transition metal nitrides. Biochemical Pharmacology, 18(4), 227–237, 2015.
 A. Alvarez Barragan, N. V. Ilawe, L. Zhong, B. M. Wong, and L. Mangolini, “A Non-Thermal Plasma Route to Plasmonic TiN Nanoparticles,” J. Phys. Chem. C, 121(4), 2316–2322, 2017.
 M. Valari, A. Antoniadis, D. Mantzavinos, and I. Poulios, “Photocatalytic reduction of Cr(VI) over titania suspensions,” Catal. Today, vol. 252, pp. 190–194, 2015.
 Barragan, A. A., Hanukovich, S., Bozhilov, K., Yamijala, S. S. R. K. C., Wong, B. M., Christopher, P., & Mangolini, L. Photochemistry of Plasmonic Titanium Nitride Nanocrystals. Journal of Physical Chemistry C, 123(35), 21796–21804, 2019.