Hydrogen sensing performance and its enhanced sensing mechanisms of hollow structured-SnO2 nanospheres activated by noble metal nanoparticles

SnO2 hollow nanospheres (HNS) were synthesized by a hydrothermal method using carbon nanospheres, and Pd nanoparticles (NPs) were decorated by irradiation with an ultraviolet light to enhance its sensing performance. Six kinds of samples were synthesized followed by the amount of decorated Pd NPs to find optimum amount of Pd NPs showing the best hydrogen sensing response. The sensor fabricated with SnO2 HNS decorated with Pd NPs for 3 h exhibits a sensing response of 121 to 100 ppm hydrogen gas, whereas a sensor fabricated with bare SnO2 HNS exhibits a sensing response of 3.1. Furthermore, its hydrogen sensing selectivity is also improved as Pd NPs are decorated. It is difficult for SnO2 HNS to distinguish hydrogen gas from other gases including NO2 gas. However, as the Pd NPs are decorated with SnO2 HNS, their sensing responses to hydrogen gas drastically enhances, whereas the sensing responses to other gases do not. This enhanced hydrogen sensing performance of the Pd NP-decorated SnO2 HNS is related to the synergistic effects of the structural features of SnO2 HNS and the catalytic effect of Pd NPs. This study demonstrates the improved hydrogen sensing performance of Pd NP-decorated SnO2 HNS and discusses its enhanced sensing mechanisms