Junhao Ma

Abstract In this study, a straightforward coassembly strategy is demonstrated to synthesize Pt sensitized mesoporous WO 3 with crystalline framework through the simultaneous coassembly of amphiphilic poly(ethylene oxide)‐ b ‐polystyrene, hydrophobic platinum precursors, and hydrophilic tungsten precursors. The obtained WO 3 /Pt nanocomposites possess large pore size (≈13 nm), high surface area (128 m 2 g −1 ), large pore volume (0.32 cm 3 g −1 ), and Pt nanoparticles (≈4 nm) in situ homogeneously distributed in mesopores, and they exhibit excellent catalytic sensing response to CO of low concentration at low working temperature with good sensitivity, ultrashort response‐recovery time (16 s/1 s), and high selectivity. In‐depth study reveals that besides the contribution from the fast diffusion of gaseous molecules and rich interfaces in mesoporous WO 3 /Pt nanocomposites, the partially oxidized Pt nanoparticles that chemically and electronically sensitize the crystalline WO 3 matrix, dramatically enhance the sensitivity and selectivity.

Foodborne pathogens like Listeria monocytogenes can cause various illnesses and pose a serious threat to public health. They produce species-specific microbial volatile organic compounds, i.e., the biomarkers, making it possible to indirectly measure microbial contamination in foodstuff. Herein, highly ordered mesoporous tungsten oxides with high surface areas and tunable pores have been synthesized and used as sensing materials to achieve an exceptionally sensitive and selective detection of trace Listeria monocytogenes. The mesoporous WO3-based chemiresistive sensors exhibit a rapid response, superior sensitivity, and highly selective detection of 3-hydroxy-2-butanone. The chemical mechanism study reveals that acetic acid is the main product generated by the surface catalytic reaction of the biomarker molecule over mesoporous WO3. Furthermore, by using the mesoporous WO3-based sensors, a rapid bacteria detection was achieved, with a high sensitivity, a linear relationship in a broad range, and a high specificity for Listeria monocytogenes. Such a good gas sensing performance foresees the great potential application of mesoporous WO3-based sensors for fast and effective detection of microbial contamination for the safety of food, water safety and public health.

With the development of internet of things and artificial intelligence electronics, metal oxide semiconductor (MOS)-based sensing materials have attracted increasing attention from both fundamental research and practical applications. MOS materials possess intrinsic physicochemical properties, tunable compositions, and electronic structure, and are particularly suitable for integration and miniaturization in developing chemiresistive gas sensors. During sensing processes, the dynamic gas-solid interface interactions play crucial roles in improving sensors' performance, and most studies emphasize the gas-MOS chemical reactions. Herein, from a new view angle focusing more on physical gas-solid interactions during gas sensing, basic theory overview and latest progress for the dynamic process of gas molecules including adsorption, desorption, and diffusion, are systematically summarized and elucidated. The unique electronic sensing mechanisms are also discussed from various aspects including molecular interaction models, gas diffusion mechanism, and interfacial reaction behaviors, where structure-activity relationship and diffusion behavior are overviewed in detail. Especially, the surface adsorption-desorption dynamics are discussed and evaluated, and their potential effects on sensing performance are elucidated from the gas-solid interfacial regulation perspective. Finally, the prospect for further research directions in improving gas dynamic processes in MOS gas sensors is discussed, aiming to supplement the approaches for the development of high-performance MOS gas sensors.

Mesoporous metal-based materials (MMBMs) have received unprecedented attention in catalysis, sensing, and energy storage and conversion owing to their unique electronic structures, uniform mesopore size and high specific surface area. In the last decade, great progress has been made in the design and application of MMBMs; in particular, many novel assembly engineering methods and strategies based on amphiphilic block copolymers as structure-directing agents have also been developed for the "bottom-up" construction of a variety of MMBMs. Development of MMBMs is therefore of significant importance from both academic and practical points of view. In this review, we provide a systematic elaboration of the molecular assembly methods and strategies for MMBMs, such as tuning the driving force between amphiphilic block copolymers and various precursors (i.e., metal salts, nanoparticles/clusters and polyoxometalates) for pore characteristics and physicochemical properties. The structure-performance relationship of MMBMs (e.g., pore size, surface area, crystallinity and crystal structure) based on various spectroscopy analysis techniques and density functional theory (DFT) calculation is discussed and the influence of the surface/interfacial properties of MMBMs (e.g., active surfaces, heterojunctions, binding sites and acid-base properties) in various applications is also included. The prospect of accurately designing functional mesoporous materials and future research directions in the field of MMBMs is pointed out in this review, and it will open a new avenue for the inorganic-organic assembly in various fields.