Radiation Synthesis of Multimetallic Nanoparticles on 1-D Metal Oxide Nanotubes via Carbothermal Shock of Carbon Nanofibers for Highly Sensitive Acetone Gas Sensors

Multi-metallic nanoparticles (MMNPs) have generated significant interest in various fields such as catalysis, bioimaging, and gas sensors due to their improved catalytic performance. Therefore, it is crucial to develop an efficient, cost-effective, and straightforward synthesis method for MMNPs, as the synthetic approach directly affects their applicability, stability, and performance. Traditional methods often involve intricate and expensive experimental procedures. Among the various approaches to synthesizing MMNPs, the carbothermal shock (CTS) synthesis has gained attention for its simple yet sophisticated mechanism. However, the CTS synthesis has a limitation, as it requires oxygenated, conductive carbon as a supporting material. To broaden the range of suitable substrates, we propose a novel and uncomplicated method that utilizes carbon support solely as a heat generator for the direct synthesis of MMNPs on SnO₂ nanotubes. The experimental procedure involves synthesizing SnO₂ nanotubes using the conventional electrospinning method, followed by loading Pt, Pd, and Ni precursors onto the synthesized SnO₂ nanotubes through immersion of SnO₂ powders in Pt, Pd, and Ni precursor solutions. The precursor-loaded SnO₂ nanotubes are then covered with a carbon nanofiber (CNF) film, and electrically-triggered Joule heating of the CNF film in a vacuum induces carbothermal shock. The successful deposition of Pt, Pd mono-metallic, PdPt, PtNi bi-metallic, and PdPtNi tri-metallic nanoparticles on SnO₂ nanotubes has been demonstrated using double cs-corrected transmission electron microscopy and energy dispersive X-ray analysis. The nanoparticle synthesis mechanism has been investigated using various analytical techniques. The MMNP-decorated SnO₂ nanotubes exhibit highly sensitive gas sensing performance, indicating the feasibility and potential of this research. This work expands the applicability of the conventional CTS synthesis method and enables the straightforward decoration of different combinations of MMNPs onto various non-carbon supports, including semiconducting metal oxide substrates.