Enhanced Room Temperature Greenhouse Gases Detection Using MOF-5 and Cobalt-Doped MOF-5 Thin Films

Greenhouse gases have increasingly caused harmful effects, such as global warming and climate change. In this work, metal-organic framework-5 (MOF-5) and cobalt-doped MOF-5 with different cobalt doping ratios (1 wt%, 5wt %, and 10 wt%) were successfully synthesized via the solvothermal method for greenhouse gases detection. Thin films of the prepared nanopowders were fabricated using the drop coating technique. Chemical, physical, and morphological characterizations for the synthetic materials were investigated using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and Brunauer‒Emmett‒Teller (BET) analysis. Hydrogen (H₂), carbon dioxide (CO₂), and nitrous oxide (N₂O) were measured as target gases for concentrations of 100 ppm and 200 ppm for each gas using a homemade gas chamber test as greenhouse gas samples. MOF-5 doped with a 10 wt% ratio of cobalt showed the highest sensor device response toward N₂O, of 137.5% at 200 ppm compared with undoped MOF-5.