A functionalized graphene-based composite coating with unique hydrogen gas barrier and long-term anti-corrosion performance

Conventional epoxy resin coatings have limited resistance to corrosion and high-pressure hydrogen environments, which severely restricts their application in hydrogen transportation. This paper innovatively proposes a unique nanohybrid two-dimensional filler, in which polydopamine-functionalized graphene nanosheets are modified with a 3-aminopropyltriethoxysilane coupling agent to bridge nano-alumina. Finally, the composite filler is introduced into an epoxy resin to fabricate a composite coating. By enhancing the interfacial interactions among graphene, alumina, and the polymer, both the hydrogen barrier performance of graphene and long-term corrosion resistance can be simultaneously improved. The composite coating containing 20 wt% Gr@PDA-APTES-Al 2 O 3 exhibited the optimal overall performance. The coating also achieved a minimum steady-state hydrogen permeation current density of 2.38 × 10 −6 A/cm 2 and a reduction-in-area-based hydrogen embrittlement susceptibility index of 67.57%. This study provides an important reference for the design of composite coatings for hydrogen pipeline protection and hydrogen energy utilization.