Novel p-n heterojunction-type rGO/CeO2 bilayer membrane for room-temperature nitrogen dioxide detection

In this paper, a novel reduced graphene oxide (rGO)/cerium oxide (CeO2) bilayer membrane was developed by facile spray and thermal reduction process for nitrogen dioxide (NO2) sensing at room temperature. Morphological and structural feature was characterized by scanning electron microscope (SEM) and spectral analyses (FTIR, UV-Vis and XPS spectra), respectively. The NO2− sensing properties results showed that rGO/CeO2 bilayer membrane exhibited 8.2 times response value of rGO one when exposed to 10 ppm NO2, which also displayed shorter response times, excellent reversibility, repeatability and selectivity. The enhanced sensing mechanism was discussed in details. It could be speculated that p-n heterojunction is formed effectively at the interface of rGO and CeO2, and more oxygen vacancies generated in CeO2 might be beneficial to the synergistic effect of heterojunction based on Ce 3d XPS analysis.