Rational integration of multifunctions is an emerging strategy to develop novel chemiresistor nano platforms with superior sensing properties. Herein, a stepwise synthesis strategy is developed to assemble two MOFs with huge mismatch into MOF-on-MOF heterojunction , which was nanoarchitectured into Fe 2 O 3 @ZnFe 2 O 4 radial-heterospindles. The Fe 2 O 3 @ZnFe 2 O 4 heterospindles exhibited outstanding selective acetone detection with multifaceted superiorities, such as high response, low limit of detection, fast response and recovery time, and good linearity in responses with a wide concentration window. An in-depth discussion revealed that such multifaceted sensing characters can be attributed to the distinct radial-heterostructure which proffer synergetic effects in the unimpeded gas diffusion with mesoporous sensing nanoarchitecture, favored interfacial charge transport in radial heterojunction, abundant active adsorption/reaction sites by rich oxygen vacancies, and exponential/efficient tuning of sensor resistance with barrier height. This synthetic strategy here may offer a new opportunity for fabricating dual-to-multi MOFs-based advanced nanostructures towards practical chemiresistor nanoplatforms with favorable multifaceted superiorities.
Metal–organic frameworks (MOFs) have garnered significant attention in recent years due to their potential application in flame-retardant polymeric materials. In this work, Fe 2 O 3 /ZnFe 2 O 4 /g-C 3 N 4 @ZIF-8 flame retardants were synthesized via solvothermal and calcination techniques, and their elemental composition and morphologies were thoroughly characterized. The flame retardancy of polyurea (PUA) composites incorporating varying dosages of these flame retardants was evaluated using cone calorimetry tests (CCT). The findings demonstrate that the incorporation of Fe 2 O 3 /ZnFe 2 O 4 /g-C 3 N 4 @ZIF-8 significantly enhanced the flame retardant properties of PUA composites. With the addition of 3 wt% of the flame retardant, the peak heat release rate (PHRR), total heat release (THR), total smoke production (TSP), and total CO yield (TCO) of the PUA composites decreased to 890.82 kW/m 2 , 131.34 MJ/m 2 , 12.30 m 2 , and 2.39 g, respectively, reflecting reductions of 33.59%, 18.59%, 29.40%, and 47.93% compared with pure PUA. The flame-retardant mechanism was systematically analyzed in both the condensed and gas phases. This study provides a robust experimental foundation and novel insights that contribute to the development of advanced flame-retardant coating materials.
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