Uniform Nanocrystal\nSpatial Distribution-Enhanced\nSnO<sub>2</sub>‑based Sensor for High-Sensitivity Hydrogen\nDetection

Hydrogen (H<sub>2</sub>) is colorless, odorless, and\nhas a wide\nexplosive concentration range (4–75 vol %), making rapid and\naccurate detection of hydrogen leaks essential. This paper demonstrates\na method to modify the spatial distribution of nanocrystals (NCs)\nby adding surfactants to improve the sensing performance. In order\nto explore its potential for H<sub>2</sub> gas-sensing applications,\nSnO<sub>2</sub>, containing different mass percentages of PdCu NCs,\nwas dispersed. The results show that the 0.1 wt % PdCu-SnO<sub>2</sub> sensor based on surfactant dispersion performs well, with a response\nto 0.1 vol % H<sub>2</sub> that is 18 times higher than that of the\nundispersed 0.1 wt % PdCu-SnO<sub>2</sub> sensor. The enhanced gas-sensing\nability after dispersion can be attributed to the fact that the uniform\ndistribution of NCs generates higher quantum efficiency and exposes\nmore active sites on the carrier surface compared to nonuniform distribution.\nThis study provides a simple, novel, and effective method to improve\nthe sensor response.