N-Carbon-Doped Binary Nanophase of Metal Oxide/Metal-Organic Framework for Extremely Sensitive and Selective Gas Response

Abstract

Metal-organic frameworks (MOFs), which are highly ordered structures exhibiting sub-nanometer porosity, possess significant potential for diverse gas applications. However, their inherent insulative properties limit their utility in electrochemical gas sensing. This investigation successfully modifies the electrical conductivity of zeolitic imidazolte framework-8 (ZIF-8) employing a straightforward surface oxidation methodology. A ZIF-8 polycrystalline layer is applied on a wafer-scale oxide substrate and subjects to thermal annealing at 300 degrees C under ambient air conditions, resulting in nanoscale oxide layers while preserving the fundamental properties of the ZIF-8. Subsequent exposure to NO2 instigates the evolution of an electrically interconnected structure with the formation of electron-rich dopants derived from the decomposition of nitrogen-rich organic linkers. The N-carbon-hybridized ZnO/ZIF-8 device demonstrates remarkable sensitivity (approximate to 130 ppm-1) and extreme selectivity in NO2 gas detection with a lower detection limit of 0.63 ppb under 150 degrees C operating temperature, surpassing the performance of existing sensing materials. The exceptional performances result from the Debye length scale dimensionality of ZnO and the high affinity of ZIF-8 to NO2. The methodology for manipulating MOF conductivity through surface oxidation holds the potential to accelerate the development of MOF-hybridized conductive channels for a variety of electrical applications. This study reports the modification of the electrical conductivity of an insulative zeolitic imidazolate framework-8 by producing nanoscale oxide layers and electron-rich dopants of nitrogen-carbon organic compounds, using a surface oxidation methodology. The successful fabrication of a semiconducting device based on the binary structure of metal oxide/metal-organic framework, which exhibits exceptional gas sensing properties is demonstrated.image