Vanadium carbide nanoparticles encapsulated in graphitic carbon network nanosheets : a high-efficiency electrocatalyst for hydrogen evolution reaction

A hierarchical nanosheet structure comprising isolated vanadium carbide nanoparticles encapsulated in a highly conductive mesoporous graphitic carbon network (VC-NS) is synthesized by a hydrothermal reaction and subsequent low-temperature magnesium thermic reaction. It has a large specific surface area and boasts highly efficient HER (hydrogen evolution reaction) activity such as very small overpotential, fast proton discharge kinetics, and excellent durability. The small Tafel slope of 56 mV dec-1 with a low overpotential of only 98 mV at 10 mA cm-2 is quite close to that of the commercial 20% Pt/C catalyst. The excellent durability is indicated by the overpotential shift of only 10 mV after 10000 cyclic voltammetric cycles at a current density of 80 mA cm-2. The high-performance precious-metal-free electrocatalyst is promising in HER and related energy generation applications.Department of Applied Biology and Chemical Technolog