Enhanced ammonia sensing properties of rGO/WS2 heterojunction based chemiresistive sensor by marginal sulfonate decoration

• Published in: Sensors and actuators. B, Chemical Chemical, 2021-06, Vol.337, p.129776, Article 129776
• Main Authors: Wang, Xueyan, Huang, Baoyu, Wu, Xiaofang, Gu, Ding, Li, Xiaogan
• Format: Article
• Language: English
• Subjects: Adsorption; Ammonia; Density functional theory; Gas sensors; Graphene; Heterojunctions; High-sensitive gas sensor; Recovery time; Room temperature; S-rGO/WS2 heterojuntion; Selectivity; Sensors; Sulfonated rGO
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2021.129776

[Display omitted] •The gas sensing properties of rGO/WS2 have been enhanced significantly by－SO3H decorating on the edge of rGO nanosheets.•The sensitivity of S-rGO/WS2 is about three times that of rGO/WS2, while the time for recovery has been shortened by half.•The enhanced sensitivity of S-rGO/WS2 are attributed to the stronger adsorption capacity of S-rGO, by DFT calculation. Two-dimensional reduced graphene oxide (rGO) nanosheets were pre-sulfonated and further incorporated by WS2 nanoflakes to form S-rGO/WS2 heterojunctions by hydrothermal synthesis. The sulfonation and WS2 incorporation in S-rGO/WS2 heterojunction have been confirmed by EDS, XPS and FTIR. The sensing performance of rGO-based chemiresistive-type sensor to ammonia at room temperature has been significantly improved by the sulfonation and incorporation of WS2 nanoflakes. The chemiresistive sensor based on S-rGO/WS2 exhibits enhanced response signals to 10∼50 ppm ammonia, while the response/recovery time is significantly shortened compared to rGO/WS2 reported previously at room temperature. It benefits from both the extra introduced active acid centers sensitive to ammonia molecules and the better desorption-ability facilitated significantly by sulfonate groups (SO3H). The adsorption energy calculation of ammonia molecule on the sulfonated graphene sheet based on density functional theory (DFT) has been performed to illustrate the adsorption capacity of SO3H group. The selectivity and stability of gas sensor based on S-rGO/WS2 have also been studied.