A triple synergistic effect from pitaya-like MoNix-MoCx hybrids encapsulated in N-doped C nanospheres for efficient hydrogen evolution

To enhance the intrinsic activity and the density of active sites of catalysts for the hydrogen evolution reaction (HER), a facile strategy of using an organic-inorganic precursor followed by carbonization is adopted to prepare ternary core-shell nanostructures composed of ultrafine hybrids of MoNi alloys and MoCx nanoparticles encapsulated in N-doped carbon nanospheres (MoNix-MoCx@NC). The well-defined pitaya-like nanostructures of MoNix-MoCx nanoparticles encapsulated by N-doped carbon nanospheres can be obtained with MoNix-MoCx hybrids as the core and ultrathin N-doped C layers as the shell. A triple synergistic effect has been achieved for the HER. The first synergistic effect from homogeneously dispersed MoNix alloys and MoCx nanoparticles can improve the intrinsic activity and conductivity of MoCx. The second synergistic effect from the MoNix-MoCx and NC shell can enhance the density of active sites and conductivity of MoNix-MoCx. The third synergistic effect from N-doped C can accelerate the charge transfer rate and improve close interaction between NC and MoNix-MoCx. The MoNix-MoCx@NC sample at an optimized low temperature of 700 degrees C exhibits excellent performance and long-term stability in both acidic and alkaline solution. It requires a lower overpotential of only 172 mV and 168 mV at 10 mA cm(-2) in acidic and alkaline solution, respectively. This work provides a new approach to design multiple synergistic effects from excellent catalytic interface through an organic-inorganic hybrid method for efficient electrocatalysis.