
Chemisorption and thermal desorption methods, such as Temperature Programmed Desorption (TPD), are widely utilized for catalyst characterization. These techniques analyze the gases released from a catalyst surface, typically detected using a Thermal Conductivity Detector (TCD) or, in some cases, a mass spectrometer. While they provide valuable insights into the number and strength of active sites, they do not reveal details about the nature of these sites, the type of adsorption, or the presence of multiple adsorption site types.
To address this limitation, the AMI-300 IR integrates standard AMI techniques with real-time catalyst surface analysis using Fourier Transform Infrared (FTIR) spectroscopy. This innovative approach enables direct observation of adsorbed species, offering a deeper understanding of the adsorption and desorption processes.
The AMI-300 IR expands upon AMI’s line of catalyst characterization instruments, which have been continuously developed and manufactured since 1984. By integrating real-time Fourier Transform Infrared (FTIR) spectroscopy with AMI’s standard detection methods, this system enables researchers to not only quantify the number and strength of active sites but also gain direct insights into the nature of adsorption processes.
IR detection can also be used during pulse chemisorption procedures to ascertain the mode(s) of adsorption at different coverages. Figure 8 illustrates the adsorption of CO on platinum as the coverage increases. Even at low coverages, all the CO is adsorbed in a single mode, linearly, and there is no evidence for “bridged” CO. These insights are uniquely obtainable through IR spectroscopy, as it directly analyzes the catalyst surface rather than solely monitoring evolved gases.
AMI Instruments AMI-300IR
Pulse chemisorption of CO on Pt by FTIR.
Ammonia can be used as a probe molecule to determine the magnitude and type of acid sites in a catalyst. Below, in figure 9, is an example of ammonia adsorbed on a silica-alumina material. Three broad bands were identified as belonging to the adsorbed ammonia, at approximately 1760, 1480, and 1380 cm-1. The band at 1480 cm-1 can be ascribed to ammonia adsorbed on Brønsted acid sites, the others to ammonia adsorbed on Lewis sites (see for example, M. Niwa et al., J. Phys. Chem. B, 110 (2006) p. 264). By carrying out temperature programmed experiments and following the absorbance of the three bands as a function of temperature, it is possible to measure the isobars for each type of adsorption and assess the strength of each adsorption process. These isobars are shown in figure 10.
It can be seen from the data above that the adsorption reflected in the 1380 cm-1 band is more strongly held than the other two, perhaps indicating a stronger Lewis-type bond.

I have been using Meritics for a number of years and they always provide outstanding service and support.
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LeanneB-375

We use Meritics for the PM service and installation of all our FlowCams . Megan has been coming to our site for a number of years. She is very efficient in her work, but most of all Megan is very helpful. We have had issues with one of instruments after the install and Megan did her utmost to try and solve it while on site, even though it wasn’t solved Megan has been in contact with the supplier of the instrument to try and solve this problem for us.
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Booking engineer visits is always easy. David Lowe, Meritics engineer is always very friendly.
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NathamM-270

Excellent service from an excellent company. Would recommend them to anyone.
BarryH-480

David, our service engineer as usual was good at communicating and setting up the recent service appointment, he arrived on time, did the service promptly and informed me of any problems. Friendly and helpful
TomA-446

I have used this company through the laboratory I work for frequently. We specialise in soil analysis, and Meritics were chosen as they have extensive knowledge of the instruments we use. We have several laser particle diffraction analysers with a service contract, and service is always very prompt and meticulous….
JamesG-2483

Meritics have covered the annual servicing of our Multisizer 4e instrument since we purchased it from them just over two years ago. The application scientist who performed the servicing was friendly, knowledgeable, and extremely helpful, happily answering a barrage of questions about how best to use and maintain the instrument. All my interactions with Meritics staff have been positive. I would happily recommend them.
RajG-62

Service second to none, both units serviced and all questions answers by engineer while on site.
RichardA-786

After owning one of our instruments for over 8 Years which was purchased from Meritics, it suffered its first breakdown. Upon contacting Meritics, I was instantly put through to an engineer who was very helpful. Upon inspection of the manual, it was decided that it would be more cost effective to have a Meritics engineer visit. The Meritics staff were very communicative and kept me up to date.

Lovely, friendly and extremely helpful. David and his team are always on call with advise and are very easy to work with and are always happy to help.
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2 people helped with the install of a Multisizer 4e. They were both very professional and friendly, answering any questions that I had. The installation was quick and the attention to good documentation practice was exceptional.
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Friendly and collaborative staff, provided a very good service.
SamK-403

We had issues with one of the aperture tubes provided by Meritics on a Friday afternoon, while very pressed for a review deadline. Meritics handled our inquiries very fast and professionally and helped us out by shipping us their spare tube to use in the mean time free of charge, while we waited for our new tube to arrive. Communication was very pleasant.
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AlexH-474

Used Meritics to conduct particle size distribution by laser diffraction. Service as last time, is very quick, well priced and professional.
I would highly recommend
GavinR-101

Always a pleasure to deal with the people at Meritics Ltd. They understand the importance of our work and the fact that our research projects have deadlines that need to be met. Consequently, problems are dealt with very quickly and professionally and they are willing to go that one step further to make sure their supply chain problems don’t become our problems. Thank you to the team for their support. It is greatly appreciated.
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