Table 1.

A resume of the some of the devices reported in this paper with the lowest limit of detection.

Material	Device	Target Gas	LOD	OT (°C)	Notes	Ref.
GO	resistive	NO2	20 ppb in dry air	150	The responses for concentrations >40 ppb are not affected by RH	[81]
GO	resistive	NO2	650 ppb (est.)	RT	Sensing tests in dry air	[82]
GO	resistive	H2	100 ppm	RT	GO shows n-type behaviour. Low response and recovery times	[83]
edge-tailored GO	FET	SO2	5 ppm	RT	Sensing tests at 65% RH	[87]
fluorinated-GO	resistive	NH3	6 ppb (est.)	RT	Sensing tests in dry air	[94]
rGO	resistive	NH3	5 ppb	RT	Sensing tests at RH < 5%	[113]
holey rGO	resistive	NO2	60 ppb	RT	Sensing tests in dry air	[116]
rGO	resistive, flexible	NO2	400 ppt	RT	Sensing tests in dry air	[117]
rGO	resistive, flexible	NO2	50 ppb in dry air	RT	Sensing tests in ambient conditions show the ability to detect 1 ppm NO2	[118]
rGO-C nanodots	resistive	NO2	10 ppb	RT	Sensing tests in dry air. High selectivity to NO2	[121]
rGO	resistive	CO2	300 ppm	RT	Sensing tests in ambient conditions	[123]
Pd-RGO	resistive	NO	2 ppb	RT	Sensing tests in N2 atmosphere	[124]
Pt-rGO	FET	H2	60 ppm	RT	Sensing tests at 11% ≤ RH ≤ 78%. Selective to H2 over CO and CH4	[126]
Cu2O NWs-rGO	resistive	NO2	64 ppb (est.)	RT	Sensing tests in N2 atmosphere	[137]
ZnO nanorods-rGO	resistive	NO2	47 ppb (est.)	RT	Sensing tests in dry air	[138]
Pd-WO3 nanobelts-rGO	resistive	H2	20 ppm	100	Sensing tests in dry air. Good selectivity to H2. Recovery time (<1 min)	[142]
SnO2 quantum wire-rGO	resistive	H2S	43 ppb (est.)	RT	Sensing tests at RH = 56–60%	[145]
MoS2	resistive	NO2	120 ppb	RT	Sensing tests in N2 atmosphere	[161]
MoS2	FET	NO2	20 ppb	RT	Sensing tests in Ar atmosphere	[162]
MoS2	resistive	NH3	300 ppb	RT	Sensing tests in N2 atmosphere	[170]
Pd-MoS2	resistive	H2	50 ppm	RT	Sensing tests in dry air	[181]
rGO-MoS2	resistive	NO2	5.7 ppb (est.) in dry air	60	Selectivity to NO2 over NH3, H2S, CO and HCHO. Small humidity effects on response	[184]
rGO-MoS2 fibres	resistive	NO2	53 ppb (est.)	RT	Sensing tests in dry air	[185]
WS2	impedance	methanol	5.6 ppm (est.)	RT	Sensing tests in dry air	[45]
WS2	resistive	NO2	100 ppb in dry air	150	Partial oxidation of WS2 flakes. Humidity does not affect the sensing response	[193]
WS2	resistive	H2	1 ppm in dry air	150	Partial oxidation of WS2 flakes. Humidity does not affect the sensing response	[193]
WS2	resistive	NO2	8 ppb	250	Sensing tests in dry air	[194]
MTCNF-WS2	resistive	NO2	10 ppb	RT	Sensing tests in dry air. Humidity affects the sensing response	[195]
Pd NPs-WS2	resistive, flexible	H2	10 ppm	RT	Sensing tests in N2 atmosphere	[198]
Exfoliated BP	resistive	NO2	20 ppb	RT	Sensing tests in dry air	[210]
Exfoliated BP	resistive	NO2	7 ppb (est.)	RT	Sensing tests in dry air	[212]
Exfoliated BP	resistive	NH3	80 ppb (est.)	RT	Sensing tests in N2 atmosphere and at 10 Torr	[214]
Pt NPs- exfoliated BP	FET	H2	<2000 ppm (est.)	RT	Sensing tests in dry air. Pt-BP covered with PMMA. Selectivity to H2.	[223]