▎ 摘　　要

Building up efficient water electrolysis system relays on the development of highly active, cost-effective, and stable electrocatalysts. Carbon-based metal-free catalysts are one of the promising candidates for this purpose. Herein, we report a facile strategy to synthesize nitrogen doped vertical graphene (N-VG) array for catalyzing hydrogen evolution reaction (HER) in acidic electrolyte. The resultant N-VG metal-free catalyst exhibits enhanced HER performance with an overpotential of 290 mV at 10 mA cm(-2) and good cycling stability. The enhanced performance is due to the enlarged surface area and optimization of electronic structure induced by the introduction of N heteroatom. Moreover, two possible enhancement mechanisms of N-VG are revealed with first-principle calculations. Our work further demonstrates the effectiveness of N doping on enhancement of HER.