Highly sensitive and fast responding CO sensor based on Co3O4 nanorods

Effect of microwave power on the thermal genesis of Co3O4 nanoparticles from cobalt oxalate micro-rods

“…Thermal decomposition of cobalt hydroxyl carbonate, previously prepared by the hydrothermal [28] or precipitation [29] methods, in air at 300 ºC was reported by other research groups. Bai et al [30] synthesized porous Co 3 O 4 nanorods by using modified microemulsion method in the presence of cetyltrimethylammonium bromide (CTAB) followed by annealing 400 °C for 3 h. Teng et al [31] employed the hydrothermal method, in which CO(NH 2 ) 2 and polyvinylpyrrolidone were used as precipitating agent and surfactant, respectively.…”

“…5), which is accompanied by an endothermic effect at 918 ºC (Fig. 6) [3,12,22,[24][25][26]29,34,35]. The first band is assigned to Co 3+ ions in an octahedral positions whereas the second one is due to the Co 2+ ions in tetrahedral positions.…”

High precision NH3 sensing using network nano-sheet Co3O4 arrays based sensor at room temperature

“…Among these, cobalt oxide, Co3O4, has received much research attention due to its high resistance to corrosion, abundant raw material and non-toxicity. It is a promising material for applications in Li-ion batteries [14][15][16], catalysts [17,18], and gas sensors [13,[19][20][21][22][23][24][25]. In particular, the oxidative catalytic activity of the Co3O4 is superior [17], thus it can be directly used to design or enhance the gas response, selectivity, and sensing kinetics [13,[19][20][21][22][23][24][25].…”

“…In particular, the oxidative catalytic activity of the Co3O4 is superior [17], thus it can be directly used to design or enhance the gas response, selectivity, and sensing kinetics [13,[19][20][21][22][23][24][25]. However, most reports on the Co3O4 sensors [13,[19][20][21]24,25] were focused on high temperature sensing applications (i.e., up to 300 o C). Up to now, the NH3 sensor based on the Co3O4 operated at room temperature has not been reported.…”

“…Development of novel nanostructured transitional metal oxides with controlled shapes and morphologies has stimulated considerable research interest due to their novel physical and chemical properties and potential wide-range applications [26][27][28]. So far, various morphological nanostructures of Co3O4 have been explored, including nanoparticles [19], nanofiber [20], nanowires [17,[29][30][31], nanotube [15,16], nanobelt [32], nanorods [13,23,24], and nano-sheets [18,33,34] using various methods including thermal oxidation, hydrothermal synthesis, electrospinning and inverse microemulsion. Co3O4 nano-sheets grown directly on substrates should have excellent sensing performance because the interconnected nano-sheets will form a network porous nanoscale system which facilitates a fast and effective gas adsorption onto the entire sensing surface, thus significantly improving sensitivity and reducing the response time.…”