Controllable nanoscale engineering of vertically aligned MoS2 ultrathin nanosheets by nitrogen doping of 3D graphene hydrogel for improved electrocatalytic hydrogen evolution

Three-dimensional (3D) porous molybdenum disulfide/nitrogen-doped reduced graphene oxide (MoS2/N-rGO) hydrogels were fabricated through a facile and controllable one-pot hydrothermal method. The nanosized MoS2 ultrathin nanosheets were uniformly and vertically dispersed on the rGO framework after nitrogen incorporation. The incorporated nitrogen in rGO played a key role for nano-scaling of MoS2 due to the protonation at pyridinic N-doping sites on carbon surface. The vertically aligned edge of nanosized MoS2 sheets, nitrogen incorporation of rGO and 3D network structure made the MoS2/N-rGO highly efficient for hydrogen evolution reaction, with improved double-layer capacitance and turnover frequency, small onset overpotential of 119 mV, low Tafel slope of 36 mV·decade−1 and superior long-time catalytic stability.

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