Active‐Site Engineering Enhanced PdRu Bimetallic Modified Hierarchical Mesoporous In ₂ O ₃ Nanoflowers for Highly Efficient Assessment of Seafood Freshness

ABSTRACT Highly sensitive detection of trimethylamine (TMA) concentration in complex monitoring environments is a pivotal technology for food freshness assessment. Herein, through an active‐site engineering strategy, PdRu‐modified hierarchical In ₂ O ₃ nanoflowers were successfully prepared by self‐assembly of mesoporous nanosheets. The 3D interconnected pore system significantly promotes the diffusion and mass transfer of TMA, while notably enhancing the interfacial collision efficiency in gas‐sensitive reactions. The PdRu/In ₂ O ₃ ‐1.0‐based sensor exhibits a sensitivity of 71.9 at 50 ppm, with a detection limit of 200 ppb, while optimizing the operating temperature range from 200°C to 140°C. Simultaneously, machine learning‐based analysis confirms the high selectivity, enabling it to identify TMA in ammonia‐containing binary mixtures with an accuracy quantified at 99.3%. Furthermore, density functional theory calculations combined with in situ/ex situ characterizations revealed that bimetallic oxygen spillover effects optimize oxygen transfer kinetics, reduce the activation energy barrier, and collectively enhance the trimethylamine adsorption energy (ΔE _ads = ‐0.51 eV) through orbital hybridization and charge redistribution mechanisms. Leveraging the advanced sensing strategy, the wireless portable sensing system is engineered for the rapid and non‐destructive evaluation of seafood freshness, enabling quality detection and cloud data transmission throughout the entire industry chain.