In₂O₃nanoparticle (NP)-decorated WO₃nanorods (NRs) were prepared using sol–gel and hydrothermal methods. The In₂O₃NRs and WO₃NPs were crystalline. WO₃NP-decorated In₂O₃NRs were also prepared using thermal evaporation and hydrothermal methods. The NO₂sensing performance of the In₂O₃NP-decorated WO₃NR sensor toward NO₂was compared to that of the WO₃NP-decorated In₂O₃NR sensor. The former showed a high response to NO₂due to a significant reduction of the conduction channel width upon exposure to NO₂. In contrast, the latter showed a far less pronounced response due to limited reduction of the conduction channel width upon exposure to NO₂. When the sensors were exposed to a reducing gas instead of an oxidizing gas (NO₂), the situation was reversed, i.e., the WO₃NP-decorated In₂O₃NR exhibited a stronger response to the reducing gas than the In₂O₃NP-decorated WO₃NR sensor. Thus, a semiconducting metal oxide (SMO) with a smaller work function must be used as the decorating material in decorated heterostructured SMO sensors for detection of oxidizing gases. The In₂O₃NP-decorated WO₃NR sensor showed higher selectivity for NO₂compared to other gases, including reducing gases and other oxidizing gases, as well as showed high sensitivity to NO₂.

^* TR: For training;

In this work, we prepared spinel-type NiCo2O4 (NCO) nanopowders as a low-cost and sensitive electrochemical sensor for nonenzymatic glucose detection. A facile and simple chemical bath method to synthesize the NCO nanopowders is demonstrated. The effect of pH and annealing temperature on the formation mechanism of NCO nanoparticles was systematically investigated. Our studies show that different pHs of the precursor solution during synthesis result in different intermediate phases and relating chemical reactions for the formation of NCO nanoparticles. Different morphologies of the NCO depending on pHs are also discussed based on the mechanism of growth. Electrochemical performance of the prepared NCO was characterized towards glucose, which reveals that sensitivity and selectivity of the NCO are significantly related with the final microstructure combined with constituent species with multiple oxidation states in the spinel structure.

^* Mean Absolute Percentage Error;