Hybridization with Ti₃C₂T_x MXene: An Effective Approach to Boost the Hydrothermal Stability and Catalytic Performance of Metal–Organic Frameworks

Abstract

Metal–organic frameworks (MOFs) have attracted increasing research enthusiasm owing to their tunable functionality, diverse structure characteristics, and large surface area. However, poor hydrothermal stability restricts the utilization of some MOFs in practical applications. Our work aims at improving the hydrothermal stability of a representative MOF, namely, HKUST-1, by incorporating a two-dimensional material Ti3C2T x MXene for the first time. A new type of hybrid material is synthesized through the hybridization of HKUST-1 and Ti3C2T x , and the obtained hybrids show improved hydrothermal stability as well as catalytic performance. The porosity of hybrids is enhanced when incorporating an appropriate amount of Ti3C2T x, and the surface area can reach 1380 m2·g–1, while the pristine HKUST-1 is 1210 m2·g–1. After the hydrothermal treatment (hot water vapor, 70 °C), the structure of hybrid materials maintains well, while the framework of HKUST-1 is severely destroyed. When catalyzing the ring-opening reaction of styrene oxide, the conversion reaches 76.7% only for 20 min, which is much higher than that of pure HKUST-1 (23.1% for 20 min). More importantly, the catalytic activity could recover without loss even after six cycles. Our hybrid materials are promising in practical catalytic applications due to their excellent hydrothermal stability, catalytic activity, and reusability.

Emerging MXene@Metal–Organic Framework Hybrids: Design Strategies toward Versatile Applications

“…This was confirmed by the MXene@HKUST-1 composite that showed high stability against moisture due its combination with MXene, which prevented the attack of water molecules on the Cu centers of HKUST-1. 43 Further, the improved catalytic activity of MXene@HKUST-1 composite for catalyzing the styrene oxide ring-opening reaction confirmed the importance of synthesizing these composites. The synergic effects of MXene and MOF hybridization showed improvement in the properties of both the MXene and MOF.…”

“…Gu and co-workers improved the stability of HKUST-1 by hybridization with Ti 3 C 2 T x (Figure 4f) via solvothermal method. 43 The hydrothermal stability of the as-synthesized composite was evaluated by treating at 70 °C for 12 h. The diffraction patterns remain unchanged even after subjecting to hydrothermal treatment, confirming that copper metal ions in the MOF were coordinated to the functional groups of Ti 3 C 2 T x surface. Due to the electrostatic interaction between the polar surface functional groups of Ti 3 C 2 T x and Cu cationic centers of HKUST, the structural robustness of such MXene@MOF hybrids was realized.…”

“…Moreover, 2D MXenes, as structural motifs in the design of hybrid materials, have demonstrated excellent catalytic performance by improving the stability and catalytic activities. 152 Recently, an attempt toward the improvement in the catalytic performance of HKUST-1 MOF was made by Gu et al 43 HKUST-1/Ti 3 C 2 T x hybrid exhibited enhanced moisture stability as well as the catalytic activity of HKUST-1 for styrene oxide ring opening reaction (Figure 10a). This reaction produces 2-methoxy-2-phenylethanol, which is an important organic solvent as well as an intermediate for chemical and medicinal research fields.…”

“…Furthermore, MXenes are making entry into development of smart hybrid materials. For instance, metallic conductivity (>15000 S/cm) and high mechanical strength (tensile strength of >500 Mpa for a micron thick Ti 3 C 2 T x film) endow MXene as an inorganic filler for enhancing electrical conductivity and mechanical properties of various low-dimensional materials. − By virtue of their chemical synthesis, MXene materials are amenable for solution processing where tunable surface chemistry offers possible routes for hybridization with other classes of materials via covalent and noncovalent interactions. 2D MXenes have been integrated with porous MOFs to augment their properties including stability, conductivity, catalytic activity, etc.…”

“…2D MXenes have been integrated with porous MOFs to augment their properties including stability, conductivity, catalytic activity, etc. − …”