CuO-Modified FePS ₃ Monolayer: A Two-Dimensional Sensing Material for Room Temperature Capture and Efficient Detection of VOCs

Although the development of gas sensing materials for room temperature operation is of great importance for environmental management, computational studies usually overlook the effectiveness of the adsorbent under realistic conditions. The FePS₃ monolayer has recently been synthesized and recognized as a novel two-dimensional (2D) material with favorable electrical properties, but its potential for gas-sensing applications remains unexplored. In this study, first-principles calculations are employed to systematically investigate the feasibility of pristine and CuO-modified FePS₃ monolayers for the detection of volatile organic compounds (VOCs). Relative energy is employed to evaluate the adsorption effectiveness of VOCs at different temperatures. The results demonstrate that VOCs are weakly physisorbed on the pristine FePS₃ monolayer, resulting in poor adsorption stability. The introduction of CuO strengthens the adsorbate-substrate interactions by enhancing orbital hybridization and charge transfer between VOCs and the FePS₃ monolayer. At room temperature, the CuO-modified FePS₃ monolayer can stably capture VOCs and achieve repeated detection of CHCl₃, CH₃Cl, and CH₂O with short recovery times. Moreover, the CuO-modified FePS₃ monolayer exhibits high sensitivity and excellent selectivity toward VOCs, enabling its use as a high-performance resistance-type gas sensor. Our work reveals the potential of the FePS₃ monolayer for gas sensing applications and promotes the design of gas sensors based on 2D metal phosphorus chalcogenides.