HiGee strategy towards large-scale synthesis of soluble covalent organic frameworks

The scale-up synthesis of covalent organic frameworks (COFs) with uniform structure and properties is of great importance for their practical applications. Here, we proposed a facile way to massively produce phthalocyanine-like COFs (COFBTC) via high-gravity intensified synthesis. Alcoholic solvent and basic catalyst were discovered synergically improved the formation of COFBTC. High concentration and reaction temperature were beneficial for high production as well. The intensified mass and heat transfer at high-gravity promoted the scaling-up of COFBTC with homogeneous structures and properties. A high space time yield of 305.9 kg center dot(m(3) D)(-1) was achieved for Fe-COFBTC under optimized condition. The massively produced Fe-COFBTC presented good solubility in alkaline and polar organic solvents, thus allow to process as homogeneous or heterogenous electrocatalyst for oxygen reduction reaction. The catalyst exhibited good performance of 0.79 V (vs. RHE, half-wave) and >95% recovery in homogeneous electroreduction of O-2 in 0.1 M KOH. A superior performance of 0.86 V was achieved by sol-gel-like processing of Fe-COFBTC on carbon paper due to the enhanced conductivity. The scale-up soluble catalysts with uniform properties provide more opportunities for practical applications of COFBTC.