A Design of Mesoporous Nitrogen-Doped Carbon Support Derived from ZIF-8 for Oxygen Reduction Reaction

Abstract

Zeolitic imidazolate framework-8 (ZIF-8) has been extensively studied as a precursor for nitrogen-doped carbon (NC) materials due to its high surface area, tunable porosity, and adjustable nitrogen content. However, the intrinsic microporous structure of the ZIF-8 limits mass transport and accessibility of reactants to active sites, reducing its usefulness in electrochemical applications. In this thesis, a soft templating approach using a triblock copolymer was used to prepare mesoporous ZIF-8-derived NC (Meso-ZIF-NC) samples. The hierarchical porous structure was investigated by varying the ratios of Pluronic F-127, NaClO₄, and toluene. The resulting Meso-ZIF- NC exhibited a widespread pore size distribution with an enhanced mesopore volume (2–50 nm), corresponding to the composition of the reaction mixtures. Pt nanoparticles were uniformly dispersed on the Meso-ZIF-NC to form Pt/Meso-ZIF-NC catalysts, which presented a high electrochemical surface area and improved oxygen reduction reaction activity. This study highlights the mesoporous structure of the support and the important role of nitrogen-doped support in improving catalytic activity, providing valuable insights into the design of supports for catalysts and catalyst layers.