Operando spectroscopy: fundamental and technical aspects of spectroscopy of catalysts under working conditions

International Congress on Operando Spectroscopy, 2–6 March, 2003, Lunteren, The Netherlands

Scope of the meeting

Catalysis plays a vital role in the chemical industry since about 90% of chemicals are produced via a catalytic process or from a precursor produced in a catalytic process. Understanding catalytic processes from a fundamental point of view has great relevance to develop new or improved catalytic materials for a sustainable society. Spectroscopic techniques are extremely powerful for catalyst characterization since they can provide intimate details about the active catalyst and reveal mechanistic insight on the catalytic process. However, the molecular structure of a catalyst is very dynamic and readily transforms when changing the environment surrounding the catalyst material. As a consequence, measuring a catalyst outside the reactor is mostly of little relevance for elucidating the active site and catalysts should always be characterized under relevant catalytic conditions. This is far from easy simply because there is a mismatch between the optimal conditions for measuring catalyst performance and spectroscopic data. This experimental gap has led, in some cases, to contradictory or, at least, confusing conclusions on the active site.

The solution is to study catalysts inside a reactor by spectroscopic means without making major concessions in, e.g., time scale, reaction temperature, reaction pressure and reactor design. Catalyst performance is evaluated on-line with, e.g. mass spectrometry. In other words, one should try to plug a spectrometer inside a regular catalytic reactor. Operando spectroscopy is the shortened version of spectra of a working ( operando in Latin) catalyst. Besides proposing a name for this research field, M. A. Banares (Madrid), E. Gaigneaux (Louvain-la-neuve), G. Mestl (Munich) and B. M. Weckhuysen (Utrecht) also initiated the organization of a first congress on Operando Spectroscopy. This meeting took place in Lunteren (The Netherlands) from 2–6 March, 2003. There were about 150 participants from 21 different countries. The scientific program consisted of 10 invited lectures, 30 oral contributions and more than 50 posters. Although the majority of the papers were on heterogeneous catalysis, there were also several studies on homogeneous catalysis as well. Furthermore, the majority of the abstract submissions were on the use of vibrational spectroscopy. There was also an exhibition of currently available operando spectroscopic instrumentation. The conference ended with a special afternoon to commemorate the important scientific achievements of Prof. D. C. Koningsberger on the application of EXAFS spectroscopy in catalysis on the occasion of his 65th birthday.

Selected research articles presented at the meeting are collected in this Special Issue of PCCP after a regular refereeing procedure. In many cases you will notice that the term in situ is still used by many authors. The reason is simply because there is only a small number of real operando studies already out in the literature and the presented work should be regarded as important steps toward the operando approach. As a consequence, the collection of papers in this issue provides a comprehensive overview of the state of the art and also forms a basis for further research in the field of operando spectroscopy. Due to the success and the many positive responses from the participants a Second International Congress on Operando Spectroscopy is planned for the year 2006.

Plate1 Prof. Koningsberger was commemorated during the Operando conference for his seminal contributions on EXAFS spectroscopy on the occasion of his 65th birthday.

---