First-Principles Guided Design of Pd-Decorated V2O5/Porous Silicon Composites for High-Performance NO2 Sensing at Room Temperature

A Pd-decorated V₂O₅/porous silicon (Pd-V₂O₅/PSi) composite was synthesized via magnetron sputtering for enhanced NO₂ gas sensing. The material's morphology and composition were systematically characterized, and its gas sensing performance was evaluated through comprehensive experimental measurements and first-principles calculations. The decoration of Pd nanoparticles significantly improved the sensing capabilities of the V₂O₅/PSi composite, particularly enhancing sensitivity and response/recovery characteristics. Experimental results revealed a 3.1-fold increase in response to specific NO₂ concentrations (ppm level) compared to the undecorated V₂O₅/PSi sensor. The composite exhibited rapid NO₂ response at room temperature with excellent selectivity, reproducibility, and long-term stability. First-principles calculations elucidated the structural, electronic, and adsorption properties of the Pd-V₂O₅/PSi composite, uncovering the gas sensing mechanism in NO₂ environments. This combined experimental and theoretical study provides valuable insights for developing advanced gas sensors and lays a foundation for optimizing metal oxide-based sensing materials.