Porous N-doped Graphitic Carbon Assembled One Dimensional Hollow Sstructures As High Performance Electrocatalysts For ORR

Development of metal-free oxygen reduction reaction (ORR) catalysts is of great importance for overcoming drawbacks of scarce resource and poor durability when using Pt-based materials as catalysts for ORR. Doped graphitic carbons have gradually become an overwhelming candidate for electrocatalysts of ORR due to tunable electronic properties and porous structures, as well as abundant available carbon precursors such as organic compounds, metal organic frameworks (MOFs) and covalent organic material (COM).Herein, a new way for CdTe@ZIF-8 nanofibers was designed and sythesied, then it used as a metal free catalyst for ORR.Firstly, we developed a sacrificial template by engineering CdTe QDs assembled nanowires, then take advantage of the interaction between polyvinylpyrrolidone (PVP) and MOFs to inducing the precursors of zeolitic imidazole framework structures (ZIF-8) nucleation and growth to form CdTe@ZIF-8 nanofibers.Then, nitrogen (N)-doped graphitic carbons with one-dimensional hollow/porous structures was prepared through high-temperature carbonization. In contrast to N-doped graphitic carbons derived from ZIF-8 nanocrystals, one-dimensional hollow/porous N-doped graphitic carbons exhibited better electrocatalytic activity for ORR based on higher diffusion-limited current density and more positive half-wave potential in 0.1 M KOH solution. The superior performance was attributed to CdTe@ZIF-8 precursor that produced anisotropic assembled structures of carbons, leading to low electron-trahnsfer resistance, and hollow and hierarchical porous structures by evaporation of other components from cores and joint between ZIF-8 nanocrystals, facilitating O2 mass transport.