Room temperature formaldehyde sensors with enhanced performance, fast response and recovery based on zinc oxide quantum dots/graphene nanocomposites

Abstract

Novel zinc oxide quantum dots (ZnO QDs) decorated graphene nanocomposites were fabricated by a facile solution-processed method. ZnO QDs with a size ca. 5 nm are nucleated and grown on the surface of the graphene template, and its distribution density can be easily controlled by the reaction time and precursor concentration. The ZnO QDs/graphene nanocomposite materials enhance formaldehyde sensing properties by 4 times compared to pure graphene at room temperature. Moreover, the sensors based on the nanocomposites have fast response (ca. 30 seconds) and recovery (ca. 40 seconds) behavior, excellent room temperature selectivity and stability. The gas sensing enhancement is attributed to the synergistic effect of graphene and ZnO QDs. The electron transfer between the ZnO QDs and the graphene is due to oxidation process of the analyzed gas on the ZnO QDs' surface. This proposed gas sensing mechanism is experimentally proved by DRIFT spectra results. The ZnO QDs/graphene nanocomposites sensors have potential applications for monitoring air pollution, especially for harmful and toxic VOCs (volatile organic compounds).

Graphene-wrapped WO3 nanospheres with room-temperature NO2 sensing induced by interface charge transfer

“…The details of the preparation procedure of graphene were elaborated in our previous work [23]. The obtained graphene (0.0037 g) was dissolved in ethanol (25 ml) under magnetic stirring to obtain a dispersed evenly solution.…”

A facile route to synthesize transition metal oxide/reduced graphene oxide composites and their lithium storage performance

“…The RGO shows two main bands at 1326. 4 The composites were further examined using X-ray photoelectron spectroscopy (XPS), as shown in Fig. 4.…”

“…[14][15][16][17][18] As a result, high conductivity RGO was obtained in both cases. Because of the presence of large amounts of HCl or H 2 SO 4 , the product is only RGO. Therefore, this method is not suitable to produce metal oxide/graphene composites.…”

“…Recently, they have found a broad range of applications in fields such as energy storage in supercapacitors 1 and Li ion batteries, 2 energy conversion, 3 gas sensing, 4 and photocatalysis. 5 Therefore, the preparation and application of MO/graphene composite materials has become a highly topical area.…”

Nanocube In2O3@RGO heterostructure based gas sensor for acetone and formaldehyde detection

“…36 Huang et al have synthesized ZnO QDs/ graphene nanocomposites and studied the room temperature formaldehyde sensing properties with improved performance and fast response and recovery times. 37 Recently our group, Mishra et al have studied the highly sensitive, selective and stable H 2 & LPG gas sensor based on RGO/SnO 2 QD hybrid nanostructure.…”