Graphene based Carbon Monoxide Gas Sensor Operating at Room Temperature

Abstract

Graphene has got significant scientific attention because of its special chemical, mechanical and electrical properties. This highly strong two dimensional (2D) material has prospective application in gas sensors. Carbon monoxide gas sensor are very important for human health and safety. Carbon monoxide is highly toxic gas and tough to detect because of its colorless and odorless characteristics. Carbon monoxide can get into human blood through lungs or skin. It moves into the tissues where it binds with oxygen and decrease the amount of oxygen there. This leads to headache, dizziness, confusion and even death at high concentration and longtime exposure. Herein, we report the use of defected Graphene (usually called reduced Graphene Oxide), Nitrogen doped reduced Graphene oxide (N-doped rGO) and composites of reduced Graphene Oxide (rGO) with nanoparticle of metal oxide (Fe3O4, CoOOH) and MOFs (ZIF-67, Ni-BDC) for carbon monoxide sensing at ambient conditions. Graphene oxide is prepared by chemical oxidation of graphite and converted into reduce graphene oxide (rGO) by using phenyl hydrazine. Metal Oxide nanoparticles (Fe3O4 and CoOOH) and MOFs (ZIF-67 and Ni-BDC) were successfully incorporated in rGO and employed for carbon monoxide sensing. Nitrogen doping in graphene was successfully done by using ammonium nitrate as nitrogen source and tested for carbon monoxide gas sensor. The prepared materials GO, rGO, Fe3O4, CoOOH, ZIF-67,Ni- BDC and their composites were characterized by X-ray diffraction pattern, Scanning Electron Microscopy, and FT-IR spectroscopy. Reduced graphene oxide has shown 14 % sensitivity with response time of 120s while nitrogen doped reduced graphene oxide shows 80% response towards 1000ppm of CO with response time of 30s. Among Hybrids, rGO/Fe3O4 hybrid has shown no response at room temperature while rGO/CoOOH, rGO/ZIF67 and rGO/Ni-BDC shows 34%, 90% and 38% response towards 1000ppm of CO respectively. ZIF-67 gives highest sensitivity (90%) in 20s for 1000ppm of CO level and is a promising candidate for CO sensing application.