Experimental and Theoretical Investigation of a Novel Acrylic Acid Gas Sensing Device Based on CuScO2 Microsheets

The interaction of a sensitive oxide with a target gas determines its chemiresistive signal; however, the lack of a fundamental theoretical model currently hinders its wide application. In this work, CuScO₂ microsheets are synthesized by a simple hydrothermal method, which brings about the first oxide-based acrylic acid gas sensor. It exhibits high selectivity for acrylic acid, outperforming other volatile organic compound (VOC) gases, including methanol, ethanol, formaldehyde, toluene, acetonitrile, and acetone, with a high response (up to 7–10 ppm acrylic acid) and an ultralow detection limit down to sub-ppm level (14 ppb) at a low operating temperature of 160°C. Compared to the chromatographic techniques, the proposed CuScO₂ gas sensor represents a prominent chemiresistive effect favorable for the simple and efficient monitoring of acrylic acid gas, which is significant for human health. In addition, the remarkable gas sensing properties of CuScO₂ are elucidated by a new mechanism based on the results of microstructural characterization and first-principles calculations followed by energy band analysis. Instead of the classic ambient oxygen ionosorption, Cu and Sc atoms on the solid surface play the crucial roles in target gas adsorption and electron transfer procedures, respectively. Such synergistic effect of metal atoms offers a new perspective for the design of material systems for advanced gas sensing devices.