Table 5.

Summary of the best performing Pd-based hydrogen gas sensors found in the literature. Pd NPs-based hydrogen sensors are not taken into account in this table.

Sensing Material	Limit of Detection	Response Time	Recovery Time	T°	Sensor Type	Ref.
Pd nanowire	0.50%	<0.08 s/~4%	nr	RT	electrical	[114]
Pd nanowire	27 ppm	4 s/~2.4%	nr	RT	electrical	[126]
Pd nanowire	<10 ppm	~ 30 s/~4%	100 s	RT	electrical	[115]
Pd nanowire	200 ppm	2 s/~5%	6 s	RT	electrical	[127]
Pd nanowire	100 ppm	<1 s/~1%	nr	RT	electrical	[116]
PdAu nanowire	0.20%	0.5 s/0–6.5%	2 s	RT	optical	[117]
Pd@Pt nanowire	500 ppm	2 s/~0.4%	2.5 s	294–376 K	electrical	[118]
Pd nanostrip	<10 ppm	12 s/~1%	nr	RT	optical	[119]
Au/SiO2/Pd MIM	0.50%	3 s/~4%	10 s	RT	optical	[105]
Pd/Au films	nr	5 s/4%	13 s	nr	optical	[121]
Pd/Mg film	<10 ppm	6 s/1%	33 s	RT	electrical	[124]
Pd/Mg-Pd film	nr	3 s/2 bar	~3 s	RT	electrical	[122]
Pd/Mg-Ni film	10 ppm	5 s/0.1%	nr	RT	electrical	[128]
Pd-V2O5 film	2 ppm	6 s/~100 ppm	21 s	373 K	electrical	[123]
Pd/ZnO film	0.10%	0.3 s/2%	18 s	353 K	nr	[51]
Pd nanotube	500 ppm	few s/1%	nr	RT	electrical	[125]
PdY film	500 ppm	4 s/~4%	nr	RT	optical	[129]
Pd gratings	50 ppm	18 s/~0.35%	nr	RT	electrical	[130]
Pd gratings	nr	4 s/~1%	nr	293–323 K	optical	[131]
Pd NWs@ZIF	600 ppm	7 s/~1%	10 s	RT	electrical	[132]
Pd film/SiC nanocauliflowers	2 ppm	7 s/~100 ppm	13 s	573 K	electrical	[133]
Pd film	48 ppm	15 s/~0.2%	nr	RT	SAW	[134]
Pd/ZnO film	59 ppm	12 s/2%	nr	RT	SAW	[112]
PdAu film	100–300 ppm	8 s/1%	2 min	RT	optical	[135]
Pd film (Pd-gate MOS transistor)	10 ppm	nr	nr	423 K	electrical	[127]
Pd film (Pd-gate MOS transistor)	1 ppm	1s/20 ppm	3 s	423 K	electrical	[129]