Enhanced NH Sensing Performance of Mo Cluster-MoS Nanocomposite Thin Films via the Sulfurization of Mo Cluster Iodides Precursor.

The high-performance defect-rich MoS dominated by sulfur vacancies as well as Mo-rich environments have been extensively studied in many fields, such as nitrogen reduction reactions, hydrogen evolution reactions, as well as sensing devices for NH, which are attributed to the under-coordinated Mo atoms playing a significant role as catalytic sites in the defect area. In this study, the Mo cluster-MoS composite was creatively synthesized through a one-step sulfurization process via H/HS gas flow. The Mo cluster iodides (MIs) coated on the fluorine-doped tin oxide (FTO) glass substrate via the electrophoretic deposition method (i.e., MI@FTO) were used as a precursor to form a thin-film nanocomposite. Investigations into the structure, reaction mechanism, and NH gas sensing performance were carried out in detail. The results indicated that during the gas flowing, the decomposed Mo cluster iodides played the role of template and precursor, forming complicated Mo cluster compounds and eventually producing MoS. These Mo cluster-MoS thin-film nanocomposites were fabricated and applied as gas sensors for the first time. It turns out that after the sulfurization process, the response of MI@FTO for NH gas increased three times while showing conversion from p-type to n-type semiconductor, which enhances their possibilities for future device applications.