Crystalline and Stable Hierarchical Porous Conjugated Organic Framework as an Ideal Platform for Electrosynthesis

Abstract

Fully π-conjugated organic frameworks (π-COFs) have attracted considerable attention due to their enhanced stability and conductivity compared to conventional covalent organic frameworks (COFs). Here, we report the synthesis of a crystalline and stable hierarchical porous π-COF (polyphthalocyanine, HPPc) and demonstrate its potential as an ideal electrosynthesis platform. The as-synthesized crystalline HPPc possesses a high surface area (∼324 m² g^–1), plentiful inherent micropores (1.4 nm), along with hard-template-induced, uniform, and interconnected mesopores (35 nm). This dual-porosity design can lead to improved active site dispersion and mass diffusion. Moreover, the long-range ordering brought by high crystallinity enables the precise customization of active sites as needed. Anchored with nickel and cobalt atoms, the optimized catalyst exhibits an outstanding oxygen evolution reaction performance, including a competitive overpotential of 305 mV at 10 mA cm^–2 and a low Tafel slope of 40 mV dec^–1, significantly surpassing commercial RuO₂. This work opens a new avenue for the rational design and synthesis of chemically stable and crystalline hierarchical porous π-COFs for various applications.