Uniform Nanocrystal Spatial Distribution-Enhanced SnO₂-based Sensor for High-Sensitivity Hydrogen Detection

Hydrogen (H₂) is colorless, odorless, and has a wide explosive concentration range (4-75 vol %), making rapid and accurate detection of hydrogen leaks essential. This paper demonstrates a method to modify the spatial distribution of nanocrystals (NCs) by adding surfactants to improve the sensing performance. In order to explore its potential for H₂ gas-sensing applications, SnO₂, containing different mass percentages of PdCu NCs, was dispersed. The results show that the 0.1 wt % PdCu-SnO₂ sensor based on surfactant dispersion performs well, with a response to 0.1 vol % H₂ that is 18 times higher than that of the undispersed 0.1 wt % PdCu-SnO₂ sensor. The enhanced gas-sensing ability after dispersion can be attributed to the fact that the uniform distribution of NCs generates higher quantum efficiency and exposes more active sites on the carrier surface compared to nonuniform distribution. This study provides a simple, novel, and effective method to improve the sensor response.