Size-controlled flow synthesis of metal-organic frameworks crystals monitored by in-situ ultraviolet-visible absorption spectroscopy

Size-controlled flow synthesis of nanoporous particles are of considerable interest for future industrial applications, however, is facing challenges due to lack of in-situ method for size-characterization in fluidic environment. We present that ultraviolet-visible (UV-vis) absorption spectroscopy can be integrated into a flow-synthesis system which was produced by femtosecond laser micromachining. The shift of the absorption peak position of the ex-situ and in-situ UV-vis spectra correlates to variation of size of porous metal-organic frameworks crystals. ZIF-67 crystals with a size in the range from 200 nm to 1025 nm are fabricated with the assistance of tri-ethylamine under monitoring of in-situ UV-vis spectra. The ZIF-67 crystals are converted into nanoporous carbons particles with controlled sizes. These materials show size-dependent performance in Na-ion battery and size-independent performance in metal/H2O seawater battery. (C) 2020 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.