Ag-Modified 3D Reduced Graphene Oxide Aerogel-Based Sensor with an Embedded Microheater for a Fast Response and High-Sensitive Detection of NO₂

Abstract

A chemiresistive gas sensor based on a three-dimensional Ag-modified reduced graphene oxide (3D Ag-rGO) aerogel is reported. We improve the graphene-based sensor performance by optimization of operating temperature, chemical modification, and new design of the material geometrical structure. The self-assembly and Ag nanoparticle (NP) decoration of the Ag-rGO aerogel are realized by a facile, one-step hydrothermal method. An integrated low-power microheater fabricated on a micromachined SiO2 membrane is employed to enhance the performance of the sensor with a fast response to NO2 and a shortened recovery time. The 3D Ag-rGO-based sensor at a temperature of 133 °C exhibits the highest response. At the same time, the response to other gases is suppressed while the response of the Ag-rGO sensor toward ammonia at 133 °C is reduced to half of the value at room temperature, demonstrating a greatly improved selectivity toward NO2. Additionally, the sensor exhibits a remarkably fast response to 50 ppb NO2 and a low limit of detection of 6.9 ppb.

Graphene‐Based Heterostructure Composite Sensing Materials for Detection of Nitrogen‐Containing Harmful Gases

“…seemed to play an important role in accelerating response/recovery process of gas sensors of graphene-based heterostructure composite sensing materials as well as improving gas response. [95,[106][107][108][109][110] Cui et al reported that the rGO modified with Ag nanoparticles showed higher response to NH 3 with faster response/recovery speed(response/ recovery time:6 s/10 s) than that of pristine rGO based sensor (Figure 5a). [95] The response/recovery time was defined as the time needed for a sensor to change/recover more than 63.2% of the maximum sensitivity.…”

“…Ag-S-rGO [109] Nanosheets NO 2 RT 50 (R 0 −R g )/R 0 = 74.6% 12/20 3D Ag-rGO aerogel [110] Ag NPs are distributed on rGO sheets NO 2 133 0.08 (R 0 −R g )/R 0 = 8.6% 75/89.5…”

Nitrogen Dioxide Gas Sensor Based on Ag-Doped Graphene: A First-Principle Study

“…In Figure 2c, after adsorption, the contribution from H 2 O electronic states to the total DOS of Ag-Gr is localized from −9.0 eV to −3.7 eV in valence bands and from 0.4 eV to 5 eV in conduction bands. Although H 2 O can interact with Ag-Gr, the interaction could be weakened by some suitable methods, such as heating through a microheater, which is demonstrated as an effective method in our previous work [28].…”

“…Compared with these frequently reported NMPs dopants (e.g., Au, Pt, Pd) [23,26,27], Ag has more potential due to its nontoxicity, antibacterial properties, high electrical/thermal conductivity, and cost-effectiveness. In our previous work [28], we have experimentally demonstrated that Ag nanoparticles modified reduced graphene oxide materials display outstanding sensing performance toward NO 2 , including excellent sensitivity, fast response/recovery speed, low limit of detection (LOD), and good selectivity. Table 1 summarizes the comparison of the NO 2 sensing performance of different types of graphene-based materials in recent experimental works.…”

Temperature-Dependent n-Type and p-Type Sensing Behaviors of CuO Nanosheets/MEMS to NO2 Gas

“…Recent growth in industries has been accompanied by an increasing number of factories and increased air pollutants. These pollutants include sulfur dioxide (SO 2 ), carbon dioxide (CO 2 ), and nitrogen dioxide (NO 2 ). , NO 2 is a toxic pollutant that produces low visibility and acid rain, and so NO 2 sensing to reduce its toxicity to human health and the environment is an important field of study. − …”