One of the most important challenges in catalysis is the cheap, fast and efficient preparation of novel materials able to replace traditional catalysts. The combination of metal nanoparticles and mesoporous materials is an interesting alternative for the stabilisation and control of nanoparticles, aiming to achieve highly dispersed (and thus active) nanomaterials. Various methodologies have also been proposed for the synthesis and stabilisation of metal nanoparticles on porous supports including microwave irradiation, laser ablation, ultrasounds and mechanochemical milling. Continuous flow processes can provide a number of significant benefits for synthesis/reaction processing of nanomaterials as compared to batch reactor technologies. Under continuous flow conditions, advantages including simplicity in preparation and operation, process control (flow rate, temperature, etc.), flexibility, higher productivity and controllable reaction conditions can easily achieved to provide an alternative and comparatively practical approach for potential industrially scale-up syntheses as compared to traditional protocols. A simple, innovative and efficient continuous flow methodology for the direct preparation of supported nanoparticles on porous materials using metal precursor solution flowing through heated packed-bed reactors containing the support material has been developed. The main objective of the work was to study the deposition of iron oxide (Fe2O3) nanoparticles on Al-SBA-15. The effect of the flow rate of the precursor solution, temperature and nature of the support material and metal loading has been investigated. Results indicated that optimum conditions comprised short residence times (typically flow rates of 0.5 mL min-1 and below) under mild heating (150 C) to achieve optimum materials in terms of nanoparticle size and structure and catalytic activity. The support was found to have a remarkable effect in both loading and distribution/agglomeration of nanoparticles in the system, with a previously reported Fe/Al synergy also observed in the prepared nanomaterials which leads to optimum results. The catalytic activity of the different continuous flow preparation iron containing nanomaterials was subsequently tested in a range of heterogeneously catalyzed processes to illustrate the applicability and versatility of synthesized materials.

Continuous flow preparation of iron oxide nanoparticles supported on mesoporous silicates

251st National Meeting (2016)

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