Ce-doped ZnO nanostructures: A promising platform for NO2 gas sensing.

In this comprehensive study, Ce-doped ZnO nanostructures were hydrothermally synthesized with varying Ce concentrations (0.5%, 1.0%, 1.5%, and 2.0%) to explore their gas-sensing capabilities, particularly towards NO 2. Structural characterization revealed that as Ce doping increased, crystal size exhibited a slight increment while band gap energies decreased. Notably, the 0.5% Ce-doped ZnO nanostructure demonstrated the highest NO 2 gas response of 8.6, underscoring the significance of a delicate balance between crystal size and band gap energy for optimal sensing performance. The selectivity of the 0.5% Ce-doped ZnO nanostructures to NO 2 over other gases like H 2 , acetone, NH 3 , and CO at a concentration of 100 ppm and an optimized temperature of 250 °C was exceptional, highlighting its discriminatory prowess even in the presence of potential interfering gases. Furthermore, the sensor displayed reliability and reversibility during five consecutive tests, showcasing consistent performance. Long-term stability testing over 30 days revealed that the gas response remained almost constant, indicating the sensor's remarkable durability. In addition to its robustness against humidity variations, maintaining effectiveness even at 41% humidity, the sensor exhibited impressive response and recovery times. While the response time was swift at 11.8 s, the recovery time was slightly prolonged at 56.3 s due to the strong adsorption of NO 2 molecules onto the sensing material hindering the desorption process. The study revealed the intricate connection between Ce-doping levels, structure, and gas-sensing. It highlighted the 0.5% Ce-doped ZnO nanostructure as a highly selective, reliable, and durable NO 2 gas sensor, with implications for future environmental monitoring and safety. [Display omitted] • Pure ZnO and Ce-doped ZnO nanostructures were hydrothermally synthesized and characterized. • 0.5% Ce-doped ZnO demonstrated superior NO 2 gas response, emphasizing critical doping levels for optimal sensing. • High gas response of 8.6–100 ppm NO 2 at optimal temperature of 250 °C with fast response and recovery times. • Consistent performance over five tests and stability over 30 days highlighted the gas sensor's reliability. • Robust against humidity, effective at 41%, emphasizing practical applicability. [ABSTRACT FROM AUTHOR]