2.4. Characterization of MOF nanoparticles
2.4.1. Characterization ofUiO-66(Zr)-NH2and UiO-66(Zr/Ti)-NH2
The morphology of the UiO-66(Zr)-NH2 and UiO-66(Zr/Ti)-NH2 nanoparticles was analyzed using a Gemini 500 (Zeiss, Germany) scanning electron microscopy SEM instrument. A Nicolet Fourier-transform infrared FTIR spectrometer (Thermo Scientific, USA) was used to analyze the chemical structure of the nanoparticles. A TTR-III (Rigaku, Japan) X-ray diffraction (XRD) apparatus was used to obtain the XRD profiles of the samples. Synchrotron radiation photoelectron spectroscopy (SRPES) measurements were performed at the photoemission end-station of the BL10B beamline at the National Synchrotron Radiation Laboratory (Hefei, China). The N2 adsorption–desorption isotherms of the nanoparticles were obtained using an Autosorb iQ (Quantachrome, USA) gas sorption analyzer at 77 K. Before testing, approximately 100 mg of MOF samples were activated via heating at 150 °C for 5 h under high vacuum. The zeta potentials of the nanoparticles were determined using a Zetasizer Nano ZS90 (Malvern, UK) device in DI water at pH 7.0.
The metal content (Zr, Ti) of the UiO-66(Zr/Ti)-NH2samples was determined using an Optima 7300DV (Perkin Elmer, USA) inductively coupled plasma-optical emission spectrometry (ICP-OES) system. Before ICP-OES analysis, the nanoparticle samples were digested using a hydrofluoric acid solution and diluted with DI water.
2.4.2. Characterization ofTMC-UiO-66(Zr)-NH2
A Nicolet FTIR spectrometer (Thermo Scientific, USA) was used to analyze the chemical structure of TMC-UiO-66(Zr)-NH2. The XRD spectra of the TMC-UiO-66(Zr)-NH2 samples were obtained using a TTR-III (Rigaku, Tokyo, Japan) X-ray diffractometer. The elemental and chemical compositions of the TMC-UiO-66(Zr)-NH2 samples were analyzed using an ESCALAB250 (Thermo Scientific, USA) X-ray photoelectron spectroscopy (XPS) instrument, and a 400 MHz (Bruker, Germany) proton nuclear magnetic resonance (1H NMR) spectrometer, respectively.