A highly sensitive NO 2 gas sensor based on CeO 2 -doped ZnO heterojunction nanofibers

This experiment demonstrates the efficient synthesis of a CeO 2 -doped ZnO n-type heterojunction structure via sol-gel and electrospinning, resulting in a site-activated morphology with unique characteristics. The successful doping of CeO 2 into the crystal structure of ZnO enhances the sensitivity to the target gas, due to the presence of large amounts of surface oxygen vacancies (V o ). The results showed that the 0.6[Formula: see text]mol% CeO 2 -doped ZnO nanofibers (NFs) sample achieved optimal performance, with high response, good repeatability, and excellent selectivity. The 0.6[Formula: see text]mol% CeO 2 -doped ZnO n-type heterojunction sensor has excellent sensitivity (158%) and selectivity to NO 2 gas than that of the pure ZnO NFs sensor (28%) at 300 ∘ C under 1[Formula: see text]ppm NO 2 environment. The sensor still responds 18% even at an extremely low concentration of NO 2 gas (0.2[Formula: see text]ppm). Furthermore, the results clearly demonstrate that CeO 2 incorporation significantly enhances the sensor’s selectivity toward NO 2 , even in the presence of other interfering gases. The sensor exhibits good selectivity, repeatability, and long-term stability. These remarkable sensing properties indicate that the CeO 2 -doped ZnO n-type heterojunction structure has promising applications in detecting NO 2 from human living environments.