Microstructure and electrical properties of palladium oxide thin films for oxidizing gases detection

Palladium (II) Oxide Nanostructures as Promising Materials for Gas Sensors

“…Table 1 compares the results of X-ray analysis (layers on SiO 2 /Si substrates), the HEED method (layers on optical quartz and Al 2 O 3 substrates), and TEM micro diffraction (layers on amorphous carbon/KCl). An examination of the data presented in Table 1 shows that the X-ray analysis, HEED method, and TEM micro diffraction gave the identical results for the films oxidized at temperatures T ox = 510, 570, 770, 870, and 970 K. The results of these two methods confirm that: (1) the annealing of Pd films at T ox = 510 K does not induce the changes in their phase composition; (2) after annealing of Pd films at the T ox = 570 K, the partial oxidation takes place and gives two phase samples -a mixture of Pd and PdO; and (3) after the annealing of palladium layers at T ox = 770-970 K, the total oxidation gives homogeneous PdO films [48]. Novel Nanomaterials -Synthesis and Applications…”

“…The analysis of bright-field (Figure 3c) and dark-field (Figure 3d) TEM images proves that palladium crystalline grains form a continuous coating without an axial texture with very low density of micropores. On bright-field image, the light contrast (Figure 3c) testifies to the decrease of film thickness at grain borders [48].…”

“…It has been established that PdO thin and ultrathin film sensors gave the stable signal, and the resistance values reliably returned to the baseline at SA atmosphere [50,51]. It is necessary to note that the recovery period is quite long (600-700 s).…”

“…Prepared Pd nanostructures on different substrates were annealed at dry oxygen atmosphere for 1 h for layers with thickness 5-15 nm and for 2 h for layers with thickness 30 ± 5 nm at temperatures T ox = 510, 570, 670, 770, 870, and 1070 K. The dehumidification of oxygen at pressure 120-130 kPa (1.2-1.3 Bar) was carried out by gas flow passage through gas bubbler with concentrated sulfuric acid and further through silica tube full of ground zeolite [48].…”

Zinc Recovery through Electrolytic Refinement Using Insoluble Ir + Sn + Ta + PdOx/Ti Cathode to Reduce Electrical Energy Use

“…Titanium (Ti) electrodes with high erosion resistance and conductivity are, therefore, being used instead of lead electrodes; in particular, electrodes made of titanium plate with various insoluble catalyst coatings are being developed [8]. Insoluble catalysts include IrOx, PdOx, TaOx, and SnOx, where IrOx and PdOx are used as activators to improve the current efficiency, while TaOx and SnOx are used as a stabilizer and dispersant, respectively, to increase the electrode’s lifespan [9,10,11,12,13]. For example, in a IrOx/Ti electrode, Mn in the electrolyte is electrodeposited in an oxide form at the cathode surface to increase cell resistance, while F ions corrode the coated catalyst at the cathode surface, critically reducing the electrode efficiency and lifespan [14].…”