Chemo‐Resistive CeO ₂ ‐Decorated Y ₂ O ₃ 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.