Carbide-Induced Thermal Shock Synthesis of High-Entropy Alloy Nanoparticles Anchored on WO3 Nanofibers for High-Performance Gas Sensors.

The synthesis of high-entropy alloy nanoparticles (HEA NPs) on oxide supports with a uniform and homogeneous distribution has been a significant challenge in traditional carbothermal shock (CTS) methods. In this study, we introduce a carbide-induced thermal shock (CITS) process for synthesizing HEA NPs anchored on tungsten trioxide (WO3) nanofibers. Utilizing one-dimensional (1D) tungsten carbide (WC) nanofibers (NFs) as scaffolds, we facilitated their oxidation to WO3 while preserving structural integrity. This approach resulted in the formation of ultrasmall HEA NPs (1-3 nm) strongly anchored on the WO3 NFs, preventing grain growth and enabling a core-shell microstructure. The functionalized WO3 NFs with homogeneously distributed HEA NPs demonstrated significantly enhanced gas sensing performance, especially for hydrogen sulfide (H2S), with a response (Rair/Rgas) of 22.1 at 5 ppm. This improvement is attributed to the CITS process, which enhances the chemisorption of oxygen species and increases the density of Lewis acid sites, leading to superior catalytic performance and stability. The findings from this study demonstrate the effectiveness of the CITS method in synthesizing highly active oxide-based catalysts and its potential applications in advanced gas sensing technologies under extreme conditions.