▎ 摘　　要

Vertically oriented graphene nanohills (VGNHs) have been used to boost the hydrogen evolution reaction (HER) activities of various catalysts. To further enhance the HER efficiency, a chemical modification was applied to VGNHs, and a significant improvement was observed in this work. Specifically, the catalytic performances of electrodeposited CoP on as-grown VGNHs (CoP@VGNHs) and on HNO3-treated VGNHs (CoP@N-VGNHs) were compared. The HER performances of the CoP@N-VGNH hybrid were even superior to those of noble metals, manifesting low overpotentials (eta(10) = 30 mV in acid and eta(10) = 87 mV in alkali), fast electron transfer, and durability in both acidic and alkaline electrolytes. This emphasizes the potential of physically and chemically modified graphene in the realm of water electrolysis.