Surface Defect Generation on SnO<sub>2</sub> Nanoparticles Using High-Energy Ball Milling for H<sub>2</sub>S Gas Sensor Applications

Abstract

Hydrogen sulfide (H<sub>2</sub>S) is a highly toxic and dangerous gas with a flammable and corrosive nature, making the development of reliable gas sensors for its detection vital. This study investigated the enhancement in H<sub>2</sub>S gas sensing performance of commercial SnO<sub>2</sub> powders after high-energy milling. SnO<sub>2</sub> powders were subjected to high-energy milling for 30, 60, and 90 min and then were characterized using advanced techniques to evaluate their morphology, chemical composition, and crystallinity. The response of a pristine SnO<sub>2</sub> gas sensor, and ones where the SnO<sub>2</sub> was milled for 30, 60 and 90 min, were 2.46, 2.27, 3.01, and 1.98, respectively, to 10 ppm H<sub>2</sub>S at 300°C. Thus, the H<sub>2</sub>S gas sensing results revealed that the SnO<sub>2</sub> powders milled for 60 min exhibited the highest sensing performance. This improvement in H<sub>2</sub>S sensing performance was attributable to the reduced particle sizes achieved through the high-energy milling process, which increased the surface area and created defects on the surface of the SnO<sub>2</sub> particles, thereby enhancing the interaction between the gas molecules and sensor material. The smaller morphological size of the particles and surface defects subsequently promoted the resistance modulation crucial for H<sub>2</sub>S gas detection. This study demonstrates that high-energy ball milling can effectively boost the gas-sensing features of SnO<sub>2</sub> powders. The findings can provide guidance for enhancing the gas-sensing capabilities of other resistive sensors.