▎ 摘　　要

Besides developing a large number of catalysts for hydrogen evolution reaction (HER) in alkaline electrolytes, its conversion efficiency remained low. Herein, we have developed mixed-dimensional heterostructures of niobium disulfide (NbS2) with graphene foam grown on nickel foam (NbS2-Gr-NF). The strong lateral fusion results in activating the catalytic sites of NbS2, the three-dimensional substrate provides easy access of electrolyte to active sites and increased electrochemically active surface area, while enhanced con-ductivity provides faster transfer of electrons to and from active sites. Therefore, NbS2-Gr-NF heterostructures resulted in an exceptionally high current density of 500 mA cm(-2) at a very low overpotential of 306 mV in 1 M KOH solution and even can achieve the current density values of 914 mAcm(-2) at 338 mV only at a slight increase in overpotential (32 mV). Moreover, a Tafel value of-72 mV dec(-1) confirms that as-developed heterostructure provides fast reaction kinetics where the reaction is mainly controlled by the Volmer step. Achieving such high current density at a faster rate with high stability makes NbS2-Gr-NF heterostructures a potential candidate for water-splitting, especially in alkaline electrolytes. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.