Effects of Monocarboxylic Acid Additives on Synthesizing Metal-Organic Framework NH2-MIL-125 with Controllable Size and Morphology

The effect of monocarboxylic acids on synthesizing NH2-MIL-125 is systematically studied for the first time in this work, and the fantastic results are discussed in detail. We found that a small molecular acid (acetic acid, thioglycolic acid) mostly affects the morphology changes of NH2-MIL-125, while the pseudolinker acid (p-toluylic acid, benzoic acid) has a significantly impact on the crystal size on account of the nucleation and the crystal growth rates. Ar sorption measurement and transmission electron microscopy characterization show that samples synthesized with pseudolinker acid as additives have a hierarchical structure owing to the internal defects or caves formed in the crystal. These samples also show an excellent performance for the removal of organic pollutants by the combined effects of adsorption and photodegradation.