Preparation of reduced graphene oxide/Co₃O₄ composites and sensing performance to toluene at low temperature

Abstract

Although the gas sensing properties of p-type semiconductors (such as Co 3 O 4 ) generally are lower than those of n-type oxide semiconductors, high quality gas sensors can still be designed by various modified methods due to their distinctive surface reactivity. In the work, the rGO/Co 3 O 4 composites with different formulations have been successfully synthesized by a facile hydrothermal reaction. The morphology, structure and composition of as-prepared composites were characterized by XRD, FESEM, Raman, TG, XPS spectrum and BET analysis, respectively. The sensing tests indicate that the 5 wt% rGO composite to toluene not only exhibits the highest response and excellent selectivity, but also has linear response in concentration lower 5 ppm, indicating the composite is a promising sensing material for detection of toluene. Furthermore, the mechanism of rGO enhanced composite gas sensing is also discussed in detail, which is attributed to rGO action in composite and the formation of p-p isotype heterojunction at the interface between rGO and Co 3 O 4 .

Coupling p+n Field-Effect Transistor Circuits for Low Concentration Methane Gas Detection

“…All of them are used without any modification. The static gas sensing test system (Hanwei WS-30A, Zhengzhou, China) [ 21 , 22 , 23 , 24 ] is utilized to study the sensing property of MP-4. The load resistance card is the standard accessory of the system and p-FETs and n-FETs are soldered orderly onto the resistance card with D, S, and G electrodes shown in Figure 1 .…”

Two‐Dimensional Nanostructured Materials for Gas Sensing

“…Recent reports on graphene/metal oxide nanosheets for gas sensing include a variety of metal oxides such as SnO 2 , ZnO, TiO 2 , WO 3 , Co 3 O 4 , CeO 2 , In 2 O 3, Fe 2 O 3 , NiO . Most of these hybrid nanosheets have been synthesized by wet‐chemical, e.g., hydrothermal or solvothermal methods, providing an easy synthesis, low cost and potential for large‐scale preparation.…”

Inorganic-Diverse Nanostructured Materials for Volatile Organic Compound Sensing

“…Similar to microstructure-based volatile hydrocarbon vapors quantification (example: Sn 2+ doped NiO microspheres in Xylene detection with sub-ppm LOD) [ 389 ], nanocomposites, such as Pd/PdO/S-SnO 2 nanocomposite film, rGO/Co 3 O 4 nanocomposite, WO 3 decorated TiO 2 NPs nanocomposite, BGQD/Ag–LaFeO 3 nanocomposite, Ag/Bi 2 O 3 nanocomposite, AgO loaded LaFeO 3 nanocomposite, CuO NPs-Ti 3 C 2 Tx MXene nanocomposite, and Graphene/SnO 2 NPs nanocomposite were effectively applied in the detection of hydrocarbons as detailed in Table 5 [ 390 , 391 , 392 , 393 , 394 , 395 , 396 , 397 ]. Wherein, Ag/Bi 2 O 3 nanocomposite and Graphene/SnO 2 NPs nanocomposite were found to perform remarkably in terms of their operation temperature (at room temperature) [ 394 , 397 ].…”