Metal Exchange of ZIF-8 and ZIF-67 Nanoparticles with Fe(II) for Enhanced Photocatalytic Performance
Lehlohonolo E. Mphuthi, Elizabeth Erasmus, Еrnst H.G. Langner
Abstract
) exchange to produce bimetallic frameworks that are photocatalytically more active than their parent ZIFs. Nanosized ZIF-8 and ZIF-67 were synthesized isothermally in either water or methanol under ambient conditions. From these, Fe-containing bimetallic ZIF-8 and ZIF-67 nanoparticles were synthesized via the metal exchange, and their performance on the photocatalytic degradation of dye was evaluated. The morphology and crystal structures of the pristine ZIF-8 and ZIF-67 nanoparticles were retained to a large extent during the iron exchange. Their Brunauer-Emmett-Teller (BET) surface areas decreased by less than 15% for nZIF-8 and less than 12% for nZIF-67. The binding energy values on X-ray photoelectron spectroscopy (XPS) confirmed the preservation of the oxidation state of Fe(II) during the exchange process. A remarkably higher catalytic activity was observed for the photocatalytic degradation of dye by the Fe-exchanged nZIF-8 and nZIF-67 compared to their parent ZIFs. This proved that the incorporation of Fe(II) centers into the ZIF framework enhanced the photocatalytic activity of the framework dramatically. In addition, these catalysts can be regenerated and reused without an appreciable loss in activity.