Synthesis of Cu2O-Modified Reduced Graphene Oxide for NO2 Sensors

Abstract

Nowadays, metal oxide semiconductors (MOS)-reduced graphene oxide (rGO) nanocomposites have attracted significant research attention for gas sensing applications. Herein, a novel composite material is synthesized by combining two p-type semiconductors, i.e., Cu2O and rGO, and a p-p-type gas sensor is assembled for NO2 detection. Briefly, polypyrrole-coated cuprous oxide nanowires (PPy/Cu2O) are prepared via hydrothermal method and combined with graphene oxide (GO). Then, the nanocomposite (rGO/PPy/Cu2O) is obtained by using high-temperature thermal reduction under Ar atmosphere. The results reveal that the as-prepared rGO/PPy/Cu2O nanocomposite exhibits a maximum NO2 response of 42.5% and is capable of detecting NO2 at a low concentration of 200 ppb. Overall, the as-prepared rGO/PPy/Cu2O nanocomposite demonstrates excellent sensitivity, reversibility, repeatability, and selectivity for NO2 sensing applications.

Mechanisms of NO2 Detection in Hybrid Structures Containing Reduced Graphene Oxide: A Review

“…This generates holes in the graphene oxide [67] and, finally, causes a reduction in the structure resistance [67]. Polypyrrole (Figure 17a) is a p-type semiconductor characterized by high chemical stability, high conductivity, redox reversibility, simple preparation and low cost [69]. Therefore, polypyrrole nanostructures are a promising candidate for sensor application.…”

“…Therefore, polypyrrole nanostructures are a promising candidate for sensor application. Polypyrrole in combination with rGO (Figure 17b-f) prevents the accumulation/fusion of graphene sheets thanks to electrostatic repulsion between polypyrrole nanoparticles [69]. Additionally, it can enlarge the specific surface area, increase active sites and enhance the adsorption capacity of rGO, improving the affinity for gas [69].…”

“…Polypyrrole in combination with rGO (Figure 17b-f) prevents the accumulation/fusion of graphene sheets thanks to electrostatic repulsion between polypyrrole nanoparticles [69]. Additionally, it can enlarge the specific surface area, increase active sites and enhance the adsorption capacity of rGO, improving the affinity for gas [69]. 17a) is a p-type semiconductor characterized by high chemi stability, high conductivity, redox reversibility, simple preparation and low cost [6 Therefore, polypyrrole nanostructures are a promising candidate for sensor applicati Polypyrrole in combination with rGO (Figure 17b-f) prevents the accumulation/fusion graphene sheets thanks to electrostatic repulsion between polypyrrole nanoparticles [6 Additionally, it can enlarge the specific surface area, increase active sites and enhance adsorption capacity of rGO, improving the affinity for gas [69].…”

“…Moreover, Cu2O can prevent the restacking graphene sheets and overcome inferior gas selectivity of graphene. In the case of NO2 detection, the combination of rGO/PPy/Cu2O exhibits better N sensing performance than PPy/Cu2O composite [69]. When rGO/Cu2O/PPy composite exposed in air, oxygen is adsorbed on its surface in the form of O ions:…”

“…As a consequence, the concentration of holes increases in the hybrid material [6 Copper (I) oxide (Cu 2 O) is also a p-type semiconductor which is characterized by low cost, ease of synthesis and stability [70]. Cu 2 O have been widely studied for sensing applications in papers [69,[71][72][73][74][75][76]. In combination with rGO, Cu 2 O, such as polypyrrole, can enlarge the specific surface area, increase active sites and enhance the adsorption capacity of rGO, improving the affinity for gas [69].…”