Highly Dispersed Ultrafine Ni Particles Embedded Into MOF-74 Arrays by Partial Carbonization for Highly Efficient Hydrogen Evolution
Here we report highly dispersed ultrafine Ni nanoaprticles (NPs) embedded in the partially carbonized Ni-MOF-74 (Ni NPs/C@Ni-MOF-74) nanorod arrays were successfully fabricated by heat treatment of the rod-like Ni-MOF-74 arrays grown on Ni foam. The partial carbonization is an effective strategy to realize the homogeneous dispersion of ultrafine Ni NPs and carbon in the skeleton of rod-like Ni-MOF-74, which can prevent the encapsuled Ni NPs and carbon from the aggregation and oxidation and allow them to serve as highly efficient electrocatalysts. The fabricated Ni NPs/C@Ni-MOF-74 not only provide high specific surface area and high conductivity, but also provide good hydrophilicity and synergetic effects among Ni NPs, carbon and Ni-MOF-74 for adsorption and activation of H2O molecules. The HER electrocatalytic performance of Ni NPs/C@Ni-MOF-74 arrays can be optimized by the control of carbonization time and temperature. The optimized Ni NPs/C@Ni-MOF-74/NF shows outstanding HER catalytic performance, such as a low overpotential of 131 mV at 10 mAcm-2 and excellent durability, and it is superior to most of the recently reported MOF-based HER electrocatalysts.