Highly sensitive ammonia sensor for diagnostic purpose using reduced graphene oxide and conductive polymer

Abstract

In this study, we fabricate ammonia sensors based on hybrid thin films of reduced graphene oxide (RGO) and conducting polymers using the Langmuir-Schaefer (LS) technique. The RGO is first prepared using hydrazine (Hy) and/or pyrrole (Py) as the reducing agents, and the resulting pyrrole-reduced RGO (Py-RGO) is then hybridized with polyaniline (PANI) and/or polypyrrole (PPy) by in-situ polymerization. The four different thin films of Hy-RGO, Py-RGO, Py-RGO/PANI, and Py-RGO/PPy are deposited on interdigitated microelectrodes by the LS techniques, and their structures are characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results of ammonia sensing experiments indicate that the Py-RGO/PANI film exhibits the highest sensor response of these four films, and that it exhibits high reproducibility, high linearity of concentration dependency, and a very low detection limit (0.2 ppm) both in N2 and exhaled air environments. The current gas sensor, therefore, has potential for diagnostic purposes because it has the additional advantages of facile fabrication, ease of use at room temperature, and portability compared to conventional high-sensitivity ammonia sensors.

Hierarchical Ordered Dual‐Mesoporous Polypyrrole/Graphene Nanosheets as Bi‐Functional Active Materials for High‐Performance Planar Integrated System of Micro‐Supercapacitor and Gas Sensor

“…[ 15,21 ] Moreover, these three sensors reveal concentration‐dependent behavior and reversible response upon continuous exposure/release cycles. Notably, DM‐PG based sensor presents much higher response value (e.g., 42% at 10 ppm NH 3 ), which is better than those of SM‐PG (19%) and NM‐PG (10%) (Figure 3b), and outperforms most reported PPy based NH 3 sensors, such as PPy nanowires (5% response at 10 ppm NH 3 ), [ 40 ] PPy/rGO (7% response at 25 ppm NH 3 ), [ 41 ] PPy nanowires/nanoparticles (4% response at 50 ppm NH 3 ), [ 42 ] PPy‐rGO/polyaniline (PANI) (15% response at 10 ppm NH 3 ), [ 43 ] PPy/rGO (6% response at 1 ppm NH 3 ), [ 44 ] and PPy/graphene (10% response at 5 ppm NH 3 ) [ 45 ] (Table S1, Supporting Information). Meanwhile, DM‐PG nanosheets reveal favorable response and recovery rates compared with other reported PPy based NH 3 sensors, and the recovery time can be shortened significantly by heating (Figure S11, Supporting Information).…”

Carbon Nanomaterials: Synthesis, Functionalization and Sensing Applications

“…Graphene based electrochemical sensors are the low cost, highly sensitive and offer ease of operation for the detection of toxix substances as: 4-nitrochlorobenzene [681] (LOD = 10 nM), for the detection of hydrazine [682], sulfides [683], 4-aminophenol [684], diphenolic compounds [685], hydroquinone [686]. In addition, toxic gaseous species can be detected as reported in [687] and example are H 2 [688] (LOD: 20 ppm), CO [689] (LOD: 0.25 ppm), CO 2 [690] (sensitivity 0.17%/ppm), NO [691] (sensitivity: 63.65 pm/ppm), NO 2 [692] (LOD: 0.5 ppm) SO 2 [693] (LOD: 0.5 ppm), ammonia [694,695]. More information may be found in the review on the toxic gas detection based on graphene metal-oxides [696].…”

Multifunctional sodium alginate fabric based on reduced graphene oxide and polypyrrole for wearable closed-loop point-of-care application

“…Such approaches minimize the overall treatment expenditure and improve quality of life, leading to a fundamentally new path of healthcare management [10]. Recently, some researches indicate that the ammonia concentration in breath is associated with nephropathy, which is one of the most severe health issues in the world [11]. Due to the lose of dialysis function of kidneys for renal disease patients, urea will remain in blood and accumulate in form of ammonium ions which permeate through lung membrane via respiratory process as NH 3 gas at a level ranging from 0.82 ppm to 14.7 ppm (mean 4.88 ppm) in exhaled breath [12].…”