Construction of a Ti-Based Bimetallic Metal–Organic Framework Using a One-Pot Method for Efficient C2H2/C2H4 and C2H2/CO2 Separation

Titanium (Ti)-based metal-organic frameworks (Ti-MOFs) have attracted intensive research attention due to their low toxicity and high abundance of titanium. However, limited by the high reactivity of titanium species in the reaction system, the construction of Ti-MOFs still faces great challenges. Herein, we successfully introduced Ti into MOF-74 using a one-pot method. Powder X-ray diffraction (PXRD) combined with X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma (ICP) spectroscopy confirmed that the Ti(IV) ions were uniformly inserted into the MOF-74 structure. Our scanning electron microscopy (SEM)/energy-dispersive spectrometry (EDS) analysis showed that the Ti content was up to 44% with good sample homogeneity. The adsorption selectivity of Ti0.44/Ni0.56-MOF-74 at 1.0 bar and 298 K for C2H2/C2H4 and C2H2/CO2 (50/50, v/v) mixtures was 4.9 and 6.8, respectively, which are higher than that of pristine Ni-MOF-74. The results of our breakthrough simulation experiments revealed that the adsorption and separation performances of Ti0.44/Ni0.56-MOF-74 were greatly improved. This study provided insights for the construction of Ti-based bimetallic MOFs used for the separation of light hydrocarbons.