▎ 摘　　要

Graphene, the sp(2) carbonaceous two-dimensional (2D) material, is gaining more attention in recent electrochemical studies. However, this atomic thick electrode usually suffers with surface contamination and poor electrochemical endurance. To overcome the drawbacks, we developed a PMMA-assisted, flipped transfer method to fabricate the graphene electrode with pristine surface and prolonged lifetime in hydrogen evolution reaction (HER). The HER performances of the single-layer graphene (SLG) were evaluated on various insulating and conductive substrates, including SiO2, polymers, SLG, highly oriented pyrolytic graphite (HOPG), and copper. The parallel Tafel slopes of SLG, bilayer graphene (BLG), and HOPG suggest they share the same electrochemical activities deriving from the sp(2) carbon basal plane. Moreover, the atomic barriers, both for SLG and the single-layer h-BN (SLBN), are semitransparent in HER for the underneath copper, providing a new perspective for the 2D materials to protect and couple with the other electrochemical catalysts.