Role of ruthenium incorporation on room-temperature nonanal sensing properties of Ru-loaded urchin-like W18O49 hierarchical nanostructure

Abstract This study reports the role of ruthenium (Ru) on the gas sensing properties of urchin-like Ru-loaded W18O49 for room-temperature ppm-level sensing of nonanal, which is one of medium-chain aldehydes generated in rice aging. And this process would contribute to generating numerous volatile organic compounds (VOCs), displaying undesirable odors. In this work, pure and 0.5-2.0% Ru-loaded W18O49 hierarchical nanostructures were obtained by a simple hydrothermal method equipped with subsequent calcination treatment. Based on the analysis of the phase compositions of all as-obtained samples, the grain size decreased after incorporating a proper amount of Ru, thereby causing an improvement in the specific surface area. To investigate the effect of Ru incorporation, the gas sensing properties of pure and 0.5-2.0% Ru-loaded W18O49 were studied. The response of 1.0% Ru-loaded W18O49 sensor towards 30 ppm at room temperature was 16.1, which was 6.8 times higher than that of pure W18O49. The enhanced sensing properties were mainly due to the synergistic effect of urchin-like morphology, extensive oxygen vacancies, and the inhibition of Ru was proposed. Meanwhile, two types of rice (Japonica and Indica rice) stored at different temperatures (25, 50 and 75 oC) were utilized to verify its practicability, and the results manifest that it may be capable of distinguishing Indica rice from Japonica rice. Consequently, the fabricated sensor anticipates becoming a promising strategy for the development of a high-performance e-nose employed to inspect rice quality during storage.