Javier Pérez-Ramírez tells Journal of Materials Chemistry about his hot paper.

Could you explain the significance of your article to the non-specialist?

Dawsonite-type compounds are attractive precursors for oxide catalysts. These compounds have the ability to accommodate a large variety of divalent and trivalent cations, and calcination leads to mixed oxides with superior properties of component dispersion, surface area, and thermal stability. A detailed understanding of the decomposition process is required to optimize the thermal activation of these materials for prospective catalytic use. The scarce studies available apply traditional ex situ techniques, where the sample is arrested at a certain temperature by quenching the reaction, followed by exposure to atmosphere, handling, and analysis of the product thereby obtained. Ex situ approaches have frequently proved to be unreliable and also time consuming. In situ monitoring of solid-state reactions is highly preferred, since the sample being analyzed is truly representative of the reaction matrix in real time. Our publication applies a combination of in situ techniques to assess the evolution of metal-substituted dawsonite type-compounds towards the final oxide catalysts.

What has motivated you to conduct this work? 

This work forms part of our programme of developing metal-substituted hexaaluminates for high-temperature catalytic applications, including methane combustion, nitrous oxide decomposition, and ammonia oxidation. We often apply dawsonite-type compounds as precursors for hexaaluminates. The conditions of the thermal treatment (temperature, atmosphere, time) determine the catalytic performance. A detailed understanding of the decomposition mechanism and phase stability is required, and in situ methodologies were applied to this end. 

Where do you see this work developing in the future?

In our opinion, in situ studies should be practised on a more routine basis to fine-tune activation of catalyst precursors.

Javier Pérez-Ramírez (Benidorm, 1974) graduated in chemical engineering at the University of Alicante (1997) and earned his PhD degree at the Delft University of Technology (2002). He then moved to industry and worked for Norsk Hydro and Yara International in Norway. In 2005, he was appointed ICREA Professor and currently heads the Laboratory for Heterogeneous Catalysis at ICIQ (Tarragona, Spain). His research interests cover high-temperature catalysis, green chemistry, zeolite catalysis, transient techniques, and the synthesis and modification of nano-structured materials. Pérez-Ramírez has co-authored over 110 scientific papers and is inventor of 6 patents.