Facile fabrication of molybdenum compounds (Mo2C, MoP and MoS2) nanoclusters supported on N-doped reduced graphene oxide for highly efficient hydrogen evolution reaction over broad pH range

Abstract

• Develop new molybdenum compounds (Mo 2 C, MoP and MoS 2 ) nanoclusters supported on N-doped reduced graphene oxide. • Prepared catalysts exhibit excellent and durable electrocatalytic performance over a broad pH range. • Potential applications of ordered self-assembled composites for water splitting to produce hydrogen. Electrocatalytic water splitting for hydrogen production is highly desirable to replace oil energy. The catalytic performance is closely related to the conductivity, active sites and reaction Gibbs free energy of the catalyst. A general guideline for improving catalytic performance is to obtain porous carbon-based materials with a high surface area, plentiful defects and metal compound loading. Here, defect-rich nitrogen-doped reduced graphene oxide (RGO) with molybdenum (Mo)-based compound loading was designed through a two-step method. The peroxide-assisted step under low-temperature carbonization with an air atmosphere promotes the formation of defects, and the hydrothermal process improves the crosslinking degree to form a porous structure at a high carbonization temperature. The obtained catalysts exhibit excellent and durable electrocatalytic performance over a broad pH range. In addition, the transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) results clearly reveal the presence of defects. The theoretical analysis demonstrates that the RGO and Mo-based compounds have an efficient synergetic effect on the catalytic activity. This work provides clues for the development of new catalysts for water splitting to produce hydrogen.