Promotion on Formaldehyde Sensing of 3D Porous SnO2 by Eu Doping

The formaldehyde sensor with excellent performance has a wide range of applications in industrial production and the monitoring of many household products. Eu-doped 3D porous SnO
₂
with a pore size of 120 nm were synthesized as a base material for high-performance formaldehyde sensors. The gas sensitivity test results show that the sensitivity of 3.6% Eu-doped 3D porous SnO
₂
with a pore size of 120 nm to 20 ppm formaldehyde is 24 at an operating temperature of 230 °C, which is 1.8 times that of pure 3D porous SnO
₂
with the same aperture. Moreover, the formaldehyde sensor made of 3.6% Eu-doped 3D porous SnO
₂
with a pore size of 120 nm has good selectivity, with a selectivity coefficient of 5.5 for formaldehyde, good repeatability, and low detection limit (0.5 ppm/1.7). These excellent gas sensitivity characteristics are mainly attributed to the 3D porous SnO
₂
with a loose and nano-scale porous morphology, more oxygen vacancies and Eu doping. Therefore, the gas-sensing of the metal oxide semiconductor material can be further improved by doping.