▎ 摘　　要

The search for renewable energy resources has attracted considerable research interests in electrochemical reactions of hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) that are essential for fuel cells. Earth-abundant, eco-friendly and cost-effective transition metal compounds are emerging candidates as electrocatalysts in these reactions. Herein, we report the growth of manganese sulfide nanoparticles on three-dimensional graphene, through an easy, progressive successive ionic layer adsorption and reaction (SILAR) method, where manganese sulfide nanoparticles (MnS-NPs), diameter of 4-5 nm are homogeneously decorated on the 3D graphene matrix. The formed hybrid shows improved HER activity in 0.1 M KOH when compared to bulk MnS. Moreover, MnS-NPs@3DG is also active in catalyzing ORR, qualifying it as a new type of bifunctional electrocatalyst in alkaline media.