Core-shell-structured Ni@NiS2 encapsulated by N-doped carbon nanohorns growing on MOF to enhance oxygen evolution reaction performance at high current densities

To meet the requirements for commercial application, more and more attention has been paid to the oxygen evolution reaction (OER) catalytic performance under high-current conditions. In this article, carbon nanohorns (CNHs) filled with Ni nanoparticles can be obtained through a one-step method, and then the core-shell struc-tured Ni@NiS2 encapsulated by N-doped carbon nanohorns (Ni@NiS2@CNHs) were obtained through a vulca-nization process. Ni@NiS2@CNHs only requires a small potential of 400 mV to drive a high current density of 100 mA cm-2. Unfortunately, due to the strong agglomeration effect of nanopowders, the stability of Ni@NiS2@CNHs is slightly lower than that of other excellent catalysts. In this case, Ni+ deposited on the Ni@NiS2@CNHs was used as metal source to grow Ni-MOF by solvothermal method, ultimately obtaining Ni@NiS2@CNHs@MOF. It is found that this unique structure improves the electrocatalytic performance and stability of the composites. Thanks to the synergistic effect of multiphase nanostructures, Ni@NiS2@CNHs@MOF exhibited improved electrocatalytic performance. The underlying reason is that core-shell structured Ni@NiS2@CNHs can be stability and uniformly embedded on the layered structure of MOF, thus the long-time stability can be enhanced. To drive current density of 50 mA cm -2, 100 mA cm-2 and 200 mA cm-2 for OER, Ni@NiS2@CNHs@MOF only require potentials of 260 mV, 290 mV, and 310 mV, respectively, which is superior to most reported non noble metal catalysts. Combined with its excellent long-term stability, Ni@NiS2@CNHs@MOF can meet the requirements of commercial catalysts.