NiO nanoparticle-decorated SnO2 nanosheets for ethanol sensing with enhanced moisture resistance

Abstract

In a high relative humidity (RH) environment, it is challenging for ethanol sensors to maintain a high response and excellent selectivity. Herein, tetragonal rutile SnO 2 nanosheets decorated with NiO nanoparticles were synthesized by a two-step hydrothermal process. The NiO-decorated SnO 2 nanosheet-based sensors displayed a significantly improved sensitivity and excellent selectivity to ethanol gas. For example, the 3 mol% NiO-decorated SnO 2 (SnO 2 -3Ni) sensor reached its highest response (153 at 100 ppm) at an operating temperature of 260 °C. Moreover, the SnO 2 -3Ni sensor had substantially improved moisture resistance. The excellent properties of the sensors can be attributed to the uniform dispersion of the NiO nanoparticles on the surface of the SnO 2 nanosheets and the formation of NiO-SnO 2 p–n heterojunctions. Considering the long-term stability and reproducibility of these sensors, our study suggests that the NiO nanoparticle-decorated SnO 2 nanosheets are a promising material for highly efficient detection of ethanol.

Tailoring the selectivity of ultralow-power heterojunction gas sensors by noble metal nanoparticle functionalization

“…For example, a significant increase in sensitivity by a factor of ~ 60 and selectivity towards 200 ppm of ethanol vapors was achieved following surface functionalization of columnar ZnO:Fe films using AgO/Ag nanoparticles [4], which was confirmed by quantum mechanical calculations showing that (AgO)5 clusters change the surface chemistry of the Fe-doped zinc oxide ZnO (10-10) surface towards ethanol detection [4]. Wang et al [10] found that tetragonal rutile SnO2 nanosheets decorated with an optimum amount of 3 mol% of NiO nanoparticles increases by five times the response to 100 ppm of C2H5OH at 260 °C, compared to the sensor containing only pure SnO2 nanosheets. These findings were assigned to the formation of a p-n junction between the NiO nanoparticles and SnO2 nanosheets [10].…”

“…Wang et al [10] found that tetragonal rutile SnO2 nanosheets decorated with an optimum amount of 3 mol% of NiO nanoparticles increases by five times the response to 100 ppm of C2H5OH at 260 °C, compared to the sensor containing only pure SnO2 nanosheets. These findings were assigned to the formation of a p-n junction between the NiO nanoparticles and SnO2 nanosheets [10]. Moreover, surface functionalisation using nanoparticles of noble metals and their alloys has been used previously to fabricate sensors for the detection of VOC molecules [9,11].…”

Voltage-controlled NiO/ZnO p–n heterojunction diode: a new approach towards selective VOC sensing

“…There are primarily two ways through which sensors' selectivity can be improved-(i) using functionalized nanomaterial-based sensing layer and (ii) using pattern recognition techniques. In the first approach, metal oxides are doped with metal nanoparticles (e.g., SnO 2 or ZnO or WO 3 with Pt, Pd, and Au nanoparticles) [9][10][11] , or composites are formed with other metal oxides or two-dimensional materials (e.g., SnO 2 , ZnO with graphene or MoS 2 ) [12][13][14][15][16] . This approach though improves the sensor performance but fails to make sensors fully selective.…”

Inorganic-Diverse Nanostructured Materials for Volatile Organic Compound Sensing

“…Nanosheet structured materials were also developed for the quantification of gaseous ethanol. Wherein, Al-doped ultrathin ZnO NShs, NiO NPs decorated SnO 2 NShs, and CuO NPs decorated ultrathin ZnO NShs displayed their sensor responses to ethanol vapor [ 194 , 195 , 196 ]. However, apart from sensor responses and LODs, these materials require optimization for working temperatures, which are >250 °C, as noted in Table 2 .…”