Platinum Nanoparticle Decorated SiO₂ Microfibers as Catalysts for Micro Unmanned Underwater Vehicle Propulsion

Micro unmanned underwater vehicles (UUVs) need to house propulsion mechanisms that are small in size but sufficiently powerful to deliver on-demand acceleration for tight radius turns, burst-driven docking maneuvers, and low-speed course corrections. Recently, small-scale hydrogen peroxide (H₂O₂) propulsion mechanisms have shown great promise in delivering pulsatile thrust for such acceleration needs. However, the need for robust, high surface area nanocatalysts that can be manufactured on a large scale for integration into micro UUV reaction chambers is still needed. In this report, a thermal/electrical insulator, silicon oxide (SiO₂) microfibers, is used as a support for platinum nanoparticle (PtNP) catalysts. The mercapto-silanization of the SiO₂ microfibers enables strong covalent attachment with PtNPs, and the resultant PtNP-SiO₂ fibers act as a robust, high surface area catalyst for H₂O₂ decomposition. The PtNP-SiO₂ catalysts are fitted inside a micro UUV reaction chamber for vehicular propulsion; the catalysts can propel a micro UUV for 5.9 m at a velocity of 1.18 m/s with 50 mL of 50% (w/w) H₂O₂. The concomitance of facile fabrication, economic and scalable processing, and high performance-including a reduction in H₂O₂ decomposition activation energy of 40-50% over conventional material catalysts-paves the way for using these nanostructured microfibers in modern, small-scale underwater vehicle propulsion systems.