Urs Leo Stadler

Thermal plasma synthesis of tungsten bronze nanoparticles for near infra-red absorption applications

A novel synthesis concept based on inductively coupled thermal plasma technology is presented for the continuous high throughput production of tungsten bronze nanoparticles with high purity and tunable composition. Tungsten bronzes in nanoparticle form are of renewed technical interest for use in applications such as IR curing of coatings and heat shielding filters since they exhibit a high extinction coefficient in the near IR region but with little impact on transparency or visible color.

Large scale production of high aspect ratio graphite nanoplatelets with tunable oxygen functionality

High aspect ratio graphite nanoplatelets with tunable oxygen functionality are prepared using a two-step scalable process consisting of expansion by thermal plasma processing followed by exfoliation with ultrasonic processing. The result of this process is graphite nanoplatelets in high yield with an average particle size distribution ranging from monolayer graphene up to 10 nm in thickness, 1 to 30 μm in length/width, and a tunable carbon to oxygen (C/O) ratio from 50 to 200 without requiring any special separation or isolation techniques such as sedimentation or centrifugation. It has been demonstrated for the first time that an intermediate level of oxygen functionalization improves the ability to exfoliate expanded graphite without having a detrimental effect on electrical conductivity.