Multi-purpose structured catalysts designed and manufactured by 3D printing

This work presents an example of the design and manufacture capabilities that 3D printing can introduce in catalysis. A multi-purpose catalyst, with fast heat and mass transfer and low-pressure drop has been designed and manufactured by 3D printing. The novelty of the methodology is the combination of advanced techniques for accurate control on the micropore-level allied with a generic framework for the design of macropore and structural levels. The ability to design ordered macroporous should be combined with adequate and controllable implantation of surface functionalities. With this combination of advanced techniques for macro and micro-pore control, it is possible to produce catalysts that unlock traditional trade-off compromises between diffusion, pressure drop and heat transfer. To demonstrate this novel methodology, we have designed and 3D printed a cubic iso-reticular foam in AlSi10Mg. After producing the support, its entire internal area was anodized to high-surface alumina followed by Pt deposition. We have verified the reproducibility of this technique by manufacturing a catalyst for a demonstrator with 8 m length. The test reaction was oxidation of NO to NO2 with the main aim to accelerate this reaction for additional recovery of energy in the production of nitric acid.publishedVersio

Structural changes in SAPO-34 due to hydrothermal treatment. A NMR, XRD, and DRIFTS study

When SAPO-34 is used as an industrial MTO catalyst, structural transformations leading to permanent deactivation are inevitable. The performance loss is linked principally to a redistribution of Si in the material, leading to the formation of Si-islands/aggregates with a concomitant loss of Brønsted acidic sites and catalytic activity. In this work we have studied transformations taking place in a SAPO-34 sample after hydrothermal treatment by studying two samples with different levels of Si; 7 atomic % and 13 atomic % Si T-atoms, corresponding to about one and two Si per CHA cage respectively. The 13% Si sample contains significant amount of silicon islands in its as-synthesized form, while the 7% Si sample does not. The 7% Si sample was steamed for a week at 700 °C and a partial pressure of steam of 0.7 atm. The changes were analysed in the context of Si-island formation, and compared with the 13% Si sample. The results clearly illustrated existence of two distinct types of local aggregation of silicon: Silicon islands produced during synthesis and aggregate silicon reminiscent of silicon islands induced by hydrothermal treatment. The materials were synthesized with full 29Si isotopic enrichment and allowed us, for the first time, to characterise the multiplicity of silicon species in great detail by 29Si solid state NMR.acceptedVersio

Multi-purpose structured catalysts designed and manufactured by 3D printing

This work presents an example of the design and manufacture capabilities that 3D printing can introduce in catalysis. A multi-purpose catalyst, with fast heat and mass transfer and low-pressure drop has been designed and manufactured by 3D printing. The novelty of the methodology is the combination of advanced techniques for accurate control on the micropore-level allied with a generic framework for the design of macropore and structural levels. The ability to design ordered macroporous should be combined with adequate and controllable implantation of surface functionalities. With this combination of advanced techniques for macro and micro-pore control, it is possible to produce catalysts that unlock traditional trade-off compromises between diffusion, pressure drop and heat transfer. To demonstrate this novel methodology, we have designed and 3D printed a cubic iso-reticular foam in AlSi10Mg. After producing the support, its entire internal area was anodized to high-surface alumina followed by Pt deposition. We have verified the reproducibility of this technique by manufacturing a catalyst for a demonstrator with 8 m length. The test reaction was oxidation of NO to NO2 with the main aim to accelerate this reaction for additional recovery of energy in the production of nitric acid

Structural changes in SAPO-34 due to hydrothermal treatment. A NMR, XRD, and DRIFTS study

When SAPO-34 is used as an industrial MTO catalyst, structural transformations leading to permanent deactivation are inevitable. The performance loss is linked principally to a redistribution of Si in the material, leading to the formation of Si-islands/aggregates with a concomitant loss of Brønsted acidic sites and catalytic activity. In this work we have studied transformations taking place in a SAPO-34 sample after hydrothermal treatment by studying two samples with different levels of Si; 7 atomic % and 13 atomic % Si T-atoms, corresponding to about one and two Si per CHA cage respectively. The 13% Si sample contains significant amount of silicon islands in its as-synthesized form, while the 7% Si sample does not. The 7% Si sample was steamed for a week at 700 °C and a partial pressure of steam of 0.7 atm. The changes were analysed in the context of Si-island formation, and compared with the 13% Si sample. The results clearly illustrated existence of two distinct types of local aggregation of silicon: Silicon islands produced during synthesis and aggregate silicon reminiscent of silicon islands induced by hydrothermal treatment. The materials were synthesized with full 29Si isotopic enrichment and allowed us, for the first time, to characterise the multiplicity of silicon species in great detail by 29Si solid state NMR