Bio-Metal Organic Framework Nanofibers Incorporated to Polyaniline as a High-Performance Room Temperature Carbon Monoxide Gas Sensor

Carbon monoxide (CO) is an odorless, colorless, tasteless, and hazardous gas which is notorious as invisible silent killer. Therefore, early detection of CO at maximum permissible exposure level is crucial for both environment protection and human health safety [1]. Nanomaterials such as metal nanoparticles and nano-metal oxides have been extensively used to construct gas sensors. Metal-organic frameworks (MOFs) are a class of hybrid materials comprising metal ion-based vertices and organic ligandsinkers that serve to connect the vertices into two or three-dimensional periodic structures. The structures and properties of MOFs can be carefully tailored by selection of metal ion and organic linker building blocks. A remarkable property of MOFs is their intrinsic porosity, which renders them potentially useful for gas storage, separations, catalysis, and a variety of additional applications that rely on highly specific host–guest interactions [3]. Recently, Biomolecules have emerged as building blocks for constructing Metal-Biomolecule Frameworks (MBioFs). Biomolecules are structurally diverse and simple biomolecules, including amino acids, nucleobases, sugars, and others, are readily and naturally available. These features besides having different metal-binding sites and exhibiting multiple coordination modes make them excellent ligands to construct diverse structure of MBioFs [3]. In the present work, a room temperature CO gas sensor based on combination of two different nanofibers was fabricated. Polyaniline nanofibers in the presence of an amino acid based copper bio-metal-organic framework nanofibers (Cu-bio-MOF) was used as a novel CO sensing material. The crystalline structure, morphology, and composition of the prepared material were characterized by means of X-ray diffraction, Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectrometer, and scanning electron microscope (SEM). The gas sensing performance of the sensor was investigated toward various concentrations of CO gas ranging from 200 to 6000 ppm at room temperature. The fabricated 2.5% Cu-bio- MOF/polyaniline sensor exhibited high sensitivity, low detection limit, fast responsetime, and good selectivity. Thus, the proposed 2.5% Cu-bio-MOF/polyaniline sensor is a promising candidate for a CO gas sensing nanodevice.