Researchers at the Paul Scherrer Institute (PSI) have developed a new procedure that can be used to accurately recognize faster than before how catalysts age. To do so, they compared two samples provided by the specialty chemicals company Clariant: catalyst material that has not been used yet (vanadium phosphorus oxide, VPO) and VPO that has been used in industrial operation for four years.
As PSI reports in a press release, a new tomographic process provided an insight into the chemical composition of catalyst materials. By adding a local transmission spectroscopy method to this, the researchers were additionally able to show the chemical properties of the material in each volume element of the tomograms: the electron density, the vanadium concentration, and the degree of oxidation of the vanadium. Johannes Ihli, one of the study authors, explains: “Basically, we collected four-dimensional data.”
The team would have needed one week of pure measuring time for each of the samples. However, PSI researcher Zirui Gao achieved a new form of data acquisition, for which he developed an associated reconstruction algorithm. This enabled the researchers to shorten the measurement time to two days.
As anticipated, both samples displayed differences with regard to their pores, which provide the surface on which catalysis can occur. On a molecular level, the researchers were now able to prove for the very first time that there were voids in the atomic lattice and to determine their exact location. Gao adds: “Together with our other findings, this confirms the previous assumption that these holes in the atomic lattice can serve as additional active sites for the process of catalysis.”
According to PSI, this application is equally important for research and for industry. Zirui Gao, lead author of the study published on Wednesday, is quoted in the press release from PSI saying: “Our new, detailed results could help industrial companies optimise their catalysts and make them more durable.”