Graphene coating as a protective barrier against hydrogen embrittlement

•Graphene-coated specimens were assessed under tensile stress with hydrogen charging.•Graphene reduces the susceptibility of specimen to hydrogen embrittlement.•Graphene interrupts the hydrogen penetration by the formation of C–H sp3 bonds.•Protection mechanism of graphene was verified by experiments and theoretical approaches.

The applicability of a graphene coating as a protective barrier against hydrogen embrittlement was studied. To simulate the hydrogen embrittlement, complex environment of tensile stress with simultaneous hydrogen charging was applied. The strain at fracture, ductility and ultimate tensile strength of graphene-coated copper under the charged condition were preserved above 95% comparing uncharged bare copper. After hydrogen charging for 12 h, the hydrogen content in graphene-coated copper was lower than that in bare copper. Using attenuated total reflectance infrared spectroscopy and Raman spectroscopy, it was verified that graphene can interrupt the hydrogen penetration by the formation of C–H sp3 bonds. Unfortunately, it induced a distortion of graphene structure, which increased the defects in the graphene. Nevertheless, the graphene coating is expected to decrease the hydrogen embrittlement susceptibility of metal substrate.