Table 1.

Gas sensing performance between this work and previous works in literatures.

Materials	Concentration (ppm)	Response Rg/Ra	Working Temperature (°C)	Tres/Trec (s)	Reference
NiO microspheres modified by Sn2+	10	3	250	500/1000 s	[17]
Sn-doped NiO microspheres	1	65.4	300	280/5000 s	[15]
Ni-doped ZnO nanowires	5	42.4	400	50/200 s	[5]
Cr-doped NiO nanostructures	10	5	325	144/50 s	[16]
W-doped NiO nanotubes	200	8.7	375	178/152 s	[11]
Pd-doped WO3·H2O nanomaterials	10	21	230	-	[7]
Cr-doped NiO nanostructures	5	24.5	425	-	[8]
α-MoO3 arrays	100	19.2	370	1/20 s	[28]
Co3O4 Nanofibers	100	10	255	15/22 s	[29]
Cr-loaded NiO micropheres	5	20.9	220	-	[30]
Co-ZnO nanofibers	100	14.8	320	4/6 s	[31]
Sn-doped NiO nanostructure	100	20.2	225	298/223 s	[32]
Sn2+-doped NiO micropheres	10	30	180	470/440 s	Our work
	900 ppb	1.6	180	700/200 s