An etching-coordination strategy to construct yolk-shell structured ZIF/Fe-tannic acid composites for enhancing photothermal catalytic CO2 cycloaddition

Abstract

Highly efficient carbon dioxide (CO2 ) conversion over novel photothermal catalysts featuring a wide light absorption range to meet the energy and chemical demands is an urgent challenge. To this end, an etching-coordination strategy is designed to synthesize novel metal-organic framework/metal-tannic acid (TA) composites for photodriven CO2 cycloaddition. ZIF-8 can be partially removed by TA to yield a yolk-shell structure, facilitating multiple reflections of light and thereby improving light utilization and photothermal conversion. With the aid of coordination between the Fe3+ and -OH groups, the formation of Fe-TA networks on the surface of ZIF-8 significantly enhances its photoresponsive range. Notably, under full-spectrum illumination of 550 mW cm-2 for 10 h, ZIF-8/Fe-TA-10 achieves a catalytic yield of 96.3% with >99.9% selectivity for the coupling of CO2 and epichlorohydrin. Furthermore, the calculation results suggested that CO2 cycloaddition can be accelerated with a significantly reduced activation energy (19.4 kJ mol -1 ) in the presence of ZIF-8/Fe-TA-10. On the basis of the experimental results, a cooperative reaction mechanism coupling photothermal catalysis and photocatalysis is proposed.This work provides an available strategy for the future synthesis of MOF-based photocatalysts for catalytic and other applications.