Controlled Synthesis of Nickel Encapsulated into Nitrogen-Doped Carbon Nanotubes with Covalent Bonded Interfaces: The Structural and Electronic Modulation Strategy for an Efficient Electrocatalyst in Dye-Sensitized Solar Cells

Abstract

Developing an efficient and low-cost synthetic approach to controllably synthesize non-precious-metal counter electrode (CE) electrocatalysts with superior catalytic activity and electrochemical stability is critically important for the mass production of dye-sensitized solar cells (DSSCs). Herein, we proposed a simple, economical, and easily scalable synthetic route for copyrolysis of melamine and nickel acetate precursors to access the well-defined Ni-encapsulated and nitrogen-doped carbon nanotubes (Ni-NCNTs). The synthetic mechanism was comprehensively investigated by creatively analyzing the phase structure evolution and dynamical decomposition behaviors, and revealed the construction of Ni-NCNTs based on the Ni-catalyzed tip-growth mechanism. Furthermore, the meticulous structural design of Ni nanoparticles intercalated in N-doped CNTs endows Ni-NCNTs with homogeneously distributed Ni–C interfaces, abundant structural defects, and a porous architecture, as well as good electrical conductivity and co...