Mos2 directly grown on Graphene/Stainless steel(304) substrate using chemical vapour deposition for water splitting application

초록

"Molybdenum disulfide (MoS2), a hexagonally packed layered structure has attracted a lot of attention because of its unique spin orbit coupling, next generation switching, and opto?electronic devices. Moreover, it is earth abundant, stable, highly active, and widely reported as a promising HER electrocatalyst. Graphene, a two-dimensional carbon allotrope, is potentially attractive for electrochemical energy storage device and production. Among the various coating technologies, coatings with acid-resistant corrosiveness, while maintaining the characteristics of stainless steel are very important for researches. However hardly there are few reports are available on the growth of graphene directly on stainless steel substrates. In this work, we have grown graphene directly onto the stainless steel (SS304) substrate via atmospheric pressure chemical vapor deposition (APCVD) and MoS2 was deposited over this graphene layer by a low pressure chemical vapor deposition. The presence of few layer graphene directly grown on stainless steel substrate was confirmed using Raman Spectroscopy. From Raman mapping it was confirmed that the defect ratio Id/Ig is very less. SEM image reveals the porous nature while XPS confirms the sample is free from impurity. From Raman spectra after 100 CV cycles in 1 M KOH, 0.5 H2SO4, 3.5% NaCl the three most intense features at 1351, 1576 and 2697 cm?1 confirms that the directly grown samples have good corrosion resistance and stability. In addition to that from raman we observe the characteristic MoS2 peaks E1 2g (374 cm-1 ) and A1g (402 cm-1 ) assigned to the stretching vibration of MoS2. XPS confirms that the charge state of Mo is in 4+. The current density is 15 times higher for MoS2 when compared to stainless steel. Also for MoS2 the EIS decreases 1.5 times when compared to uncoated one. This confirms that the directly grown graphene is highly stable after 100 cycles and good HER activity was achieved.