Chemo‐Resistive CeO₂‐Decorated Y₂O₃ Heterostructured Nanosensors for Selective Ammonia Detection

Chemoresistive sensing is a predominant tool for detecting and quantifying the presence of environmentally harmful gases, such as NO x and CO x , which relies on the gradient in electrical resistance of sensors when they come into contact with these gases. This study introduces a unique CeO 2 ‐decorated Y 2 O 3 n–n heterostructured sensor demonstrating significantly enhanced chemo‐resistive sensing performance toward NH 3 . To realize the potential of metal oxide‐based chemical sensors, CeO 2 ‐Y 2 O 3 sensors have been successfully constructed via a two‐step hydrothermal/calcination methodology in varying compositions, ranging from a low 2.5–10% ceria region. UV‐DRS technique revealed the alleviated band energy from 3.51 to 3.32 eV on increasing the concentration of ceria in CeO 2 ‐Y 2 O 3 heterojunctions, which improved the sensitivity and selectivity toward NH 3 sensing by influencing their electronic structure, charge transfer kinetics, and interaction with target NH 3 molecules. Physisorption surface studies as curtained the higher specific surface area values of the as‐prepared CeO 2 ‐Y 2 O 3 nanocomposites as compared to their bare counterparts. Compared to the pure Y 2 O 3 sensor (157), the optimized 10% CeO 2 ‐Y 2 O 3 nanocomposite displayed enhanced sensing performance (738) at an optimum NH 3 molecules exposure at 275 °C. The improved sensing performance is attributed to the appropriate band energy, remarkable surface area, large oxygen vacancies and the formation of heterojunctions over the interface of the CeO 2 ‐Y 2 O 3 sensor. Further, the sensing mechanism participating in the advanced catalytic efficiency of the 10% CeO 2 ‐Y 2 O 3 has been comprehensively analyzed.