Muons provide a unique insight into the workings of an industrial catalyst
26 Mar 2026
A collaboration between ISIS and the University of Glasgow has been the first to apply muon spin spectroscopy (μSR) to study the copper-loaded zeolite catalysts that are used in diesel exhausts, which could also have future use in methane-to-methanol conversion.
The copper-exchanged zeolite SSZ-13 is the active catalyst for removing nitrous oxides from diesel engine exhausts. It has also been highlighted as having potential applications in methane-to-methanol conversion. This hugely beneficial process turns a greenhouse gas into a useful industrial chemical and could have significant industrial application.
Although the catalyst can convert methane to methanol, the exact mechanism behind this and the active sites remain a bit of a mystery., leaving a lot of room for improvement. In their study, published in ACS Chemistry of Materials, Adam Berlie from ISIS and Vain Skukauskas from the University of Glasgow, with Vain’s PhD supervisors Emma Gibson (University of Glasgow) and Ian Silverwood (ISIS), were the first to use muon spectroscopy to study this catalyst.
“This is a great example of two people being curious. The idea came out of a conversation between me and Vain, who was a PhD student at the time focusing on quasielastic neutron scattering, at an ISIS user (NMSUM) meeting,” explains Adam.
Being able to provide more detail into reaction mechanisms in catalytic materials is extremely important for our current understanding and future development of making energy processes more efficient. In the case of this system, muons have provided a level of insight, previously unseen, which would be hard to get with other methods.
Adam Berlie
In their experiment, muons act as a local probe, with the muonium atom (µ+e–) interacting directly with the active site in the zeolite. Unlike other techniques, which rely on studying how a catalyst interacts with reagents, μSR offers a unique way to study the local magnetic and electronic environments of the copper species in the active site of the catalyst directly.
“Being able to provide more detail into reaction mechanisms in catalytic materials is extremely important for our current understanding and future development of making energy processes more efficient,” adds Adam. “In the case of this system, muons have provided a level of insight, previously unseen, which would be hard to get with other methods.”
Their results showing the way muonium interacts with the copper sites can be extended to the methane-to-methanol conversion reaction; they provide compelling evidence for a multistep oxidation mechanism that involves the initial reduction of the copper centres prior to methanol formation.
This study not only gives an insight into this industrially relevant catalyst but also offers new opportunities for further local investigation of redox-active catalytic materials.
In particular, building on this research, Emma and Adam are currently advertising for a PhD position, based out of the University of Glasgow, which will apply μSR to the study of iron-based zeolites for several applications, such as shipping emissions strategies.
The full paper can be found at DOI: 10.1021/acs.chemmater.5c02981
