Ni-Based Nanoparticle-Embedded N-Doped Carbon Nanohorns Derived from Double Core–Shell CNH@PDA@NiMOFs for Oxygen Electrocatalysis
Yanli Guo, Yun Zhou, Yanli Nan, Bo Li, Xiaolong Song
Abstract
The development of highly efficient electrocatalysts for the oxygen evolution reaction (OER) plays a crucial role in many regenerative electrochemical energy-conversion systems. Herein, we report a novel double core–shell-structured CNH@PDA@NiMOF (CNH–D–NiMOF) composite based on the support of carbon nanohorns (CNHs) and the direction of polydopamine (PDA) on the synthesis of metal–organic frameworks (MOFs). It is found that this unique structure improves the electrocatalytic performance and stability of the composites. Furthermore, a controlled partial pyrolysis strategy was proposed to construct the Ni-based nanoparticle-embedded N-doped CNHs. The partial pyrolysis method preserves the framework structure of MOFs for effective substrate diffusion while producing highly active nanoparticles. This leads to the result that the Ni-based nanoparticle-embedded N-doped CNHs possess higher stability and significantly improved electrocatalytic properties. Among these derivatives, the sample prepared at a pyrolysis temperature of 400 °C (named as CNH–D–NiMOF-400) outperforms most of the reported unprecious-metal catalysts. At current densities of 20 and 100 mA·cm–2, the overpotentials of CNH–D–NiMOF-400 are 270 and 340 mV for the OER on a carbon fiber paper (CFP), respectively. The outstanding electrocatalytic properties above suggest that this composite is an excellent candidate for the substitution of noble metal-based catalysts for OER.