(296a) Development of a New Generation of Stable, Tunable, and Catalytically Active Nanoparticles Produced By the in-Situ and Ex-Situ Synthesis Methods

Nanoparticles (NPs) are revolutionizing many areas of science and technology, often delivering unprecedented improvements to properties of the conventional materials. However, despite important advances in NPs synthesis and applications, numerous challenges still remain. Development of alternative synthetic method capable of producing very uniform, extremely clean and very stable NPs is urgently needed. If successful, such method can potentially transform several areas of nanoscience, including environmental and energy related catalysis. Here we present the latest developments in demonstration of catalytically active NPs synthesis achieved by the helium nanodroplet isolation method. This alternative method of NPs fabrication and deposition produces narrowly distributed, clean, and remarkably stable NPs. The fabrication is achieved inside ultralow temperature, superfluid helium nanodroplets, which can be subsequently deposited onto any substrate. This technique is universal enough to be applied to nearly any element, while achieving high deposition rates for single element as well as composite core–shell NPs. In addition, our work also involves development of a new generation of doping-segregation method on nanoparticle synthesis. Here we studied behavior of dopants by various in-situ characterization techniques including environmental TEM, complemented by such in-situ techniques as XAFS, XRD and DRIFTS. More specifically, we investigated the effect of such conditions as reduction temperature on the size of nanoparticles. We then applied this method to prepare very active and selective catalysts for CO₂ reduction by reverse water gas shifts reaction.