CdO–ZnO nanorices for enhanced and selective formaldehyde gas sensing applications

Highly Sensitive and Selective Eco-Toxic 4-Nitrophenol Chemical Sensor Based on Ag-Doped ZnO Nanoflowers Decorated with Nanosheets

“…All the observed diffraction peaks were consistent with the JCPDS card no. 36-1451 and reported literature related to the wurtzite hexagonal phase of ZnO [ 23 , 24 , 25 ]. Furthermore, two other diffraction peaks appeared at 2θ = 38.1° and 44.3°which can be assigned to diffraction planes of Ag (111) and (200), respectively, and exhibit the Ag face-centered-cubic (fcc) crystal structure.…”

ZnO/NiO heterostructure-based microsensors used in formaldehyde detection at room temperature: Influence of the sensor operating voltage

“…However, given the state of the art, pristine ZnO, as a sensing material, has a low response for certain target gases and high working temperatures (Table 1 ). It was observed that these sensing characteristics could be improved by several strategies, such as: increasing the specific surface area by obtaining materials with different morphologies [ 9 ], adding noble metals (Au, Ag, Pt) [ 10 ], bimetallic nanoparticles (Pd–Au) [ 11 ], by efficient methods such as light irradiation [ 12 ] or by making heterostructures with other semiconductor oxides. Of these methods, the latter has been used by other researchers to obtain formaldehyde sensors.…”

Hollow ZnO nanorices prepared by a simple hydrothermal method for NO2 and SO2 gas sensors

“…Jiao et al 34 synthesized three different ZnO nanostructures, including dense nanorods, dense nanowires, and sparse nanowires, for gas sensors and found that the sparse nanowires are effective for the detection of NO 2 . Liu et al 24 prepared vertically aligned ZnO nanorods for NO 2 gas sensors, and the response value was reported to be approximately 200 toward 5 ppm NO 2 at 250 C. Zhou et al 35 used ZnO nanoowers for SO 2 sensors, and a response value of 15 was reported for 30 ppm SO 2 at an optimum working temperature of 260 C. The ZnO, and CdO-ZnO nanorices were prepared for formaldehyde gas sensing applications, 36 where the materials have a big size with a length and diameter of about 3 mn and 130 nm, respectively, without the hollow structure, leading to low adsorption sites for gas adsorption. Clearly, the gas sensing properties of ZnO are determined by its (i) crystal size, (ii) porosity, (iii) assembly, and (iv) characteristics.…”

“…Zhou et al 35 used ZnO nanoflowers for SO 2 sensors, and a response value of 15 was reported for 30 ppm SO 2 at an optimum working temperature of 260 °C. The ZnO, and CdO–ZnO nanorices were prepared for formaldehyde gas sensing applications, 36 where the materials have a big size with a length and diameter of about 3 μn and 130 nm, respectively, without the hollow structure, leading to low adsorption sites for gas adsorption. Clearly, the gas sensing properties of ZnO are determined by its (i) crystal size, (ii) porosity, (iii) assembly, and (iv) characteristics.…”