Iron Located on a Hollow Support Constructed with a Polymer-Assisted Template for Enhancing CO₂ Cycloaddition

Hollow carbon nanocages derived from postmodified metal-organic frameworks (PM-MOFs) exhibit a controllable morphology, excellent thermal stability, and a high specific surface area, making them promising candidates for heterogeneous catalysis. Herein, we employ a polymer-assisted strategy to design and fabricate a series of Fe-based catalysts for CO₂ conversion with high selectivity and stability. Briefly, the N-containing polymer was coated on the MOF via coordination bonding, followed by pyrolysis and further etching to form high-loading Fe nanoparticles (NPs) on hollow nanocages, denoted as Fe/HNR (hollow nanocage rods). The optimized Fe/HNR has highly dispersed Fe NPs and shows an extreme performance toward cyclocarbonic ester from the cycloaddition of epoxide with CO₂ with a high yield and excellent recycle test. It is far superior to other Fe NP catalysts without a hollow structure. In addition, this polymer-assisted strategy is also applicable to coat on other MOFs to form a core-shell precursor template. This proposed strategy provides not only an exceptional catalyst for the CO₂ cycloaddition reaction but also introduces a universal method for precisely designing a hollow carbon nanocage with uniformly dispersed metal NPs.