Abstract
Rational design of metal oxide heterostructures is of great importance for gas sensors to be applicable in the detection of inflammable, explosive and toxic gases. Herein, we designed CuO/In_2O_3 heterostructures with flower-like structures via a highly efficient one-step hydrothermal technique and constructed optimal structures to improve formaldehyde sensing properties. Consequently, the obtained 7-CuO/In_2O_3 flowerlike structures with uniform p-n heterostructure and a large quantity of oxygen vacancies exhibits the best sensing properties for detecting formaldehyde. The corresponding response value is 11.67-10 ppm formaldehyde at a low operating temperature of 100 °C, which is approximately 2.97 times higher than that of pure ln_2O_3 sensor (3.93 at 200 °C). Besides, the 7-CuO/In_2O_3 sensor also exhibits good reproducibility and stability, sub-ppm-level detection limit (1.38-0.5 ppm), high selectivity, and outstanding long-term stability, which benefits from the synergistic effect of strong oxygen adsorption capacity, p-n heterojunction between CuO and ln_2O_3, catalytic effect of CuO, and the unique flower-like structures, showing the great potential for practical formaldehyde detection.
NSTL
Elsevier