Micropatternable Ink Composed of MAX Phase ZIF-8 for Gas Sensing Applications

Gas sensing technologies have gained significant attention due to their applications in environmental monitoring, industrial safety, and medical diagnostics. In this study, we report the development and characterization of a micropatternable ink composed of MAX phase ZIF-8 (Zeolitic Imidazolate Framework-8) for gas sensing applications. The ink was prepared utilizing a shear mixing technique in an ice water bath, using water (0.1 wt% polyvinylpyrrolidone (PVP), average molecular weight is 10,000) as the solvent. The resulting hybrid nanomaterial, ZIF-8/Ti 3 C 2 , was investigated for its physicochemical and gas adsorption properties. Raman spectroscopy and X-ray diffraction (XRD) confirm the well-defined two-dimensional layered nanostructure of ZIF-8/Ti 3 C 2 . Fourier-Transform Infrared Spectroscopy (FTIR) indicates the presence of functional groups, such as hydroxyl, carboxyl, and titanium-oxygen bonds, on the surface of ZIF-8/Ti 3 C 2 . Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis confirms the homogeneous distribution of ZIF-8 nanoparticles on MXene nanosheets. It is observed that the particle sizes of ZIF-8 and Ti 3 C 2 were 20 nm and 1 µm respectively. Thermogravimetric (TGA) analysis demonstrate that ZIF-8/Ti 3 C 2 exhibited excellent thermal stability, with a mass loss of only 25% at 800°C. The ink exhibited specific gas adsorption properties, with the maximum quantity of N 2 adsorbed measured at 150.1564 cm 3 /g and the maximum quantity of CO 2 adsorbed measured at 4.4095 cm 3 /g. Additionally, gas absorption properties were investigated for various volatile organic compounds (VOCs), including formaldehyde, acetone, methane, ethanol, and toluene. In order to fabricate microstructured gas sensors, we employed atomized spraying technology to print the ZIF-8/Ti 3 C 2 ink onto substrates such as glass, gold, and polyethylene terephthalate (PET), utilizing a 10 mm × 10 mm mask. Prior to printing, oxygen plasma treatment was performed on all substrates to reduce the contact angle and to enhance ZIF-8/Ti 3 C 2 ink-substrate adhesion. The printed samples were subsequently vacuum-dried at 120°C for 30 minutes to obtain the final patterned structures. The thickness of the ZIF-8/Ti 3 C 2 layer on different substrates was characterized. The results demonstrate the feasibility of utilizing the ZIF-8/Ti 3 C 2 ink for the fabrication of microstructured gas sensors on various surfaces. The incorporation of MXene nanosheets within the ZIF-8 structure enhances the gas adsorption properties, thereby enabling highly sensitive gas sensing applications. The micropatternable ink offers versatility in terms of substrate choice, opening up possibilities for the integration of gas sensors in different environments. This work provides a foundation for the development of advanced gas sensing technologies, contributing to the advancement of healthcare, environmental monitoring, and industrial safety systems.