Disputation: Asbjørn Slagtern Fjellvåg

Doctoral candidate Asbjørn Slagtern Fjellvåg at the Department of Chemistry, Faculty of Mathematics and Natural Sciences, is defending the thesis “Platinum catchment by noble metal alloys and structural studies of Pt- and Rh-containing perovskites” for the degree of Philosophiae Doctor.

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Asbjørn Slagtern Fjellvåg

The Disputation will be live streamed for everyone else.
The livestream will be activated 15 minutes before the Defence starts.

Trial lecture

September 30th, 10:15 AM, Auditorium 3, Chemistry building

Trial lecture title:

‘’Synchrotron X-ray methods as basis to follow chemical reactions in-situ/operando - status and perspectives"

The trial lecture will be live streamed for everyone else.
The livestream will be activated 15 minutes before the trial lecture starts.

Kreeringssammendrag/Conferral summary 

Produksjon av kunstgjødsel til jordbruk er en av de viktigste kjemiske industriene vi har i dag. I denne prosessen brukes edelmetallet platina aktivt som katalysator, som dessverre fordamper under drift på grunn av ekstreme reaksjonsbetingelser. Dette prosjektet har fokusert på metoder for å fange inn igjen det tapte edelmetallet; et viktig bidrag for en bærekraftig og fremtidsrettet industri.

Main research findings

One of the steps in the production of synthetic nitrogen-based fertilizers is the oxidation of ammonia (NH3) to nitric oxide (NO). In this reaction, Pt/Rh (95/5 wt. %) is used as a catalyst and a significant Pt-loss occurs due to the high temperature and aggressive chemical conditions.  The Pt-loss is unavoidable without compromising the catalytic selectivity. Mitigation of the Pt-loss is performed by Pt-catchment, utilizing a Pd/Ni (95/5 wt. %) net placed downstream of the Pt/Rh catalyst, catching the evaporated Pt. A re-alloying process of Pd/Ni with Pt occurs during Pt-catchment, causing the Pd/Ni wires to swell and the net to grow into something more similar to a porous plate. Alloying Pd with Au reduces the swelling, and the nets keep their shape during operation, only at the cost of a small reduction in Pt-catchment.

For the future of industrial chemistry, oxide materials are seen as a cheaper and more environmentally friendly alternative to noble metals. In this mind-set, selected Pt- and Rh-containing perovskite oxides were synthesized for fundamental studies. The stability of the perovskite structure depend strongly on the oxidation states for the present elements and their size, allowing only certain compositions with Pt- and Rh- to synthesized.

Candidate contact information


E-mail address: a.s.fjellvag@smn.uio.no                      
Phone number: 46815288

Published Sep. 16, 2022 11:15 AM - Last modified Sep. 16, 2022 2:22 PM