Highly enhanced hydrogen sensing properties of sericin-induced exfoliated MoS2 nanosheets at room temperature

Herein, we report a simple and inexpensive strategy for the scaling-up of highly stabilized MoS2 nanosheets using a bio-waste sericin-assisted liquid phase exfoliation (LPE) method. MoS2 nanosheets (NSs) was also prepared under the same conditions but without sericin for comparison. The as-prepared samples were then identified as MoS2 NSs and sericin-MoS2 NSs. Each sample was drop casted on Si/SiO2 substrates then fabricated with interdigitated electrodes prior to studying their H-2 sensing properties. The as-fabricated sericin-MoS2 NSs exhibited better H-2 sensing properties at room temperature compared to those of the MoS2 NSs. An outstanding sensor response of 49% was reached at low ppm with an ultra-fast response time (10 s) and recovery time (6 s). This exceptional H-2 sensing performance was influenced by the adsorptive coating of sericin on the edges of the MoS2 NSs. The coating of sericin protein forms an electron depletion layer which can interact with metals (Mo and S) through their functional groups (-NH2, -COOH, -OH and -SH). Furthermore, such an interaction leads to a reduction of the electron depletion layer of exfoliated MoS2, and thereby enhances the H-2 sensitivity, stability and response/recovery time. We expect that the present strategy of sericin-MoS2 combination will satisfy the demand for exfoliated MoS2 based high performance H-2 sensors to-date.