Phase-Dependent Dual Discrimination of MoSe2/MoO3 Composites Toward N,N-Dimethylformamide and Triethylamine at Room Temperature

Herein,we present, a chemiresistive-type gas sensor composed oftwo-dimensional 1T-2H phase MoSe2 and MoO3. Mixed phase MoSe2 and MoSe2/MoO3 composites were synthesized via a facile hydrothermal method. Thestructure analysis using X-ray diffraction, Raman spectroscopy, andX-ray photoelectron spectroscopy revealed the formation of differentphases of MoSe2 at different temperatures. With increasein synthesis temperature from 180 to 200 & DEG;C, the relative percentageof 1T and 2H-MoSe2 phases changed from 80 to 48%. On theother hand, at 220 & DEG;C, 2H-MoSe2 was obtained as amajor component. The gas sensing properties of individual MoSe2 and composites were investigated at room temperature towardvarious analytes. The obtained results revealed that composites possessimproved sensing features as compared with individual MoSe2 or MoO3. Data also revealed that the composite with dominating1T-phase exhibits relatively higher response (10%, at 10 ppm) fordimethylformamide (DMF) compared to triethylamine (TEA) (3%, at 10ppm). In contrast, the composite with larger 2H-phase exhibited affinitytoward TEA and had a relative response of about 2%. Therefore, selectivityof a sensor device can be tuned by an appropriately designed MoSe2/MoO3 composite. These results signify the importanceof MoO3-based composites with dual-phase MoSe2 for successfully discriminating between DMF and TEA at room-temperature.