Constructing Nd2O3-ZnO Heterojunctions in Porous Nanolayered Architectures Via Rare-Earth Modification for Highly Sensitive and Stable Ethanol Detection

To solve the problems of low sensitivity, high detection limit, high operating temperature, and poor stability of metal oxide semiconductor ethanol sensors, Nd-modified ZnO composites were synthesized via a simple hydrothermal method by leveraging the unique advantages of rare earth elements in electronic structure and catalytic activity. The introduction of Nd species into the porous nanolayered structure of ZnO induced lattice distortion and generated an Nd 2 O 3 -ZnO heterojunction. This modification increased the oxygen vacancy defects in the material, promoted reactions between adsorbed oxygen species and ethanol, and thereby effectively enhanced the gas-sensing performance of the sensor. The results indicated that the 2% Nd-ZnO sensor achieved a lower operating temperature (375 °C), a high response (147 toward 100 ppm ethanol, 3.3 times that of pure ZnO), and an ultralow theoretical detection limit (80 ppb), together with excellent selectivity, repeatability, and long-term stability. These results demonstrate a heterojunction-defect co-engineering strategy enabled by rare-earth modification, providing an effective and practical pathway for designing high-performance ZnO-based ethanol gas sensors.