High performance langasite based SAW NO2 gas sensor using 2D g-C3N4@TiO2 hybrid nanocomposite

Edge-enriched MoS2 nanosheets modified porous nanosheet-assembled hierarchical In2O3 microflowers for room temperature detection of NO2 with ultrahigh sensitivity and selectivity.

Controlling the anatase TiO2 based-rectangular nanoplates (NPs) with {001} faces have gained immense interest in gas sensors applications, since the rectangular NPs of {001} planes are highly reactive for the adsorption of oxygen species that led to significant improvement in gas sensing performance. In this work, we report on the room temperature (RT) NO2 gas sensing performances of hybrid nanocomposites with the interpenetrated network using p-Phenylenediamine-reduced graphene oxide (PrGO) decorated TiO2 NPs. The fabricated TiO2 NPs/PrGO heterostructure sensor demonstrated the superior NO2 response (∼14.9% to 100 ppm of NO2) compared to TiO2/rGO and pristine TiO2 nanoplates. On the other hand, the TiO2 NPs/PrGO heterostructure device showed high sensitivity, repeatability and excellent selectivity with short response/recovery times towards NO2 gas at RT. Further, the performances of the TiO2NPs/PrGO gas sensor was accelerated by UV irradiation (λ = 365 nm), and the response was found as ~35.68% to 100 ppm of NO2 at RT, which was ~2.35-fold times higher than the dark condition. The high gas sensing performance would be attributed to the electrical sensitization of PrGO and the ample interface between TiO2 NPs and PrGO that stimulated the charge separation with faster charge transport characteristics. Our strategy and results shed new light to exploit diverse functionalized materials to the high response gas sensors at RT. 

PrGO decorated TiO2 nanoplates hybrid nanocomposite for augmented NO2 gas detection with faster gas kinetics under UV light irradiation

In this work, 2D g-C 3 N 4 nanosheets were employed as a sensitive interface for high-performance NO 2 SAW gas sensors, operating at various environmental conditions. The immense sensitivity to NO 2 gas is attributed to the enhanced mass loading effect. 

Highly sensitive g-C3N4 nanosheets as a potential candidate for the effective detection of NO2 gas via langasite-based surface acoustic wave gas sensor

This paper reports a new type of high-performance formaldehyde gas sensor using g-C3N4 nanosheets to modify the surface of In2O3 nanospheres as the sensing material. SEM and TEM results showed that g-C3N4 nanosheets were uniformly distributed on the surface of In2O3. The samples were characterized by XPS, and it was found that both oxygen defects (Ov) and chemically adsorbed oxygen (Oc) in the composite material were increased. The sensor performance under different loadings of g-C3N4 was systematically studied. Especially for 12 wt% loading the response of the sensor material with to 100 ppm formaldehyde reached 1405, which was 2 times bigger than that of pure In2O3. Importantly, it also had a low operating temperature of 119〬C and a short response time of 1 s. The enhancement of sensing performance could be attributed to the realization of rapid electron transfer and the exposure of high-density active center by constructing a unique n-n heterostructure. This research provides an effective method for preparing a formaldehyde sensor with fast response, high sensitivity and low power consumption. 

G-C3N4/In2O3 composite for effective formaldehyde detection

In this work, we demonstrated a single device of g-C3N4/GaN NRs heterostructure with dual functionality for self-powered ultraviolet light photodetector and selective NO2 gas sensor at room temperature. The g-C3N4/GaN NRs heterostructure demonstrated excellent photoresponse to UV illumination (λ = 392 nm) at zero bias with linear dependence on illumination power. Under 1.35 mW/cm−1 illumination power, the device exhibited high responsivity∼20 mA/W, and detectivity ∼5.16 × 1012 cmHz1/2/W. On the other hand, the g-C3N4/GaN NRs heterostructure exhibited remarkable response of 7.8 % for 5 ppm NO2 gas, while pristine GaN NRs showed negligible response. The potentiality of the gas sensor is further boosted by irritation of UV and visible lights, and the limit of the detection enriched to 500 ppb under UV illuminations at RT. UV light (P = 1.35 mW/cm2) greatly intensified the response by five-fold, and notably stimulated the recovery signal of the device for 500 ppb NO2. The increased response of heterostructure is ascribed to the sensitization of g-C3N4 and the adequate interface between g-C3N4 and GaN NRs that promoted the charge transport and separation effectively. The photodetector and NO2 gas sensing mechanism of g-C3N4/GaN NRs junction is discussed in detail by using energy band diagram.

Interaction activated interfacial charge transfer in 2D g-C3N4/GaN nanorods heterostructure for self-powered UV photodetector and room temperature NO2 gas sensor at ppb level

Nguyen Thi KimPhung

Papers

Interaction activated interfacial charge transfer in 2D g-C3N4/GaN nanorods heterostructure for self-powered UV photodetector and room temperature NO2 gas sensor at ppb level