Why smaller is better in catalytic washcoats
Can you guess what your body has in common with the solar panel on your roof? Here’s a hint: if you’ve eaten today, this process might be at work right now!
The answer: they both rely on the action of catalysts for their processes to work. Catalysts are key to both natural and man-made processes – from turning your food into energy to the catalytic converter in your car. Essentially, a catalyst is something that facilitates chemical reactions, so the greater the surface area of a catalytic material, the more effective the catalysis because it can interact with more of the reactive material.
And it doesn’t get much smaller than the nanoscale, the next frontier in catalytic technology! That’s why nanoparticles of catalytic materials – such as platinum – are being used in a growing range of applications. Tiny particles equal huge surface area. But what’s the most effective way to deliver these particles?
Power washes
Washcoats are advanced coatings that keep the nanoparticles of catalytic material in suspension, making them easy to apply to a variety of different surfaces. For example, catalytic washcoats can improve the efficiency of photovoltaic cells and reduce the quantities of precious metals needed to manufacture catalytic converters.
However, washcoats containing nanostructured catalysts need to have stable formulations to ensure the homogeneous distribution of catalyst materials during processing. Given the extremely small size of the particles involved, this can be tricky to achieve.
There are two main factors to consider: nanoparticle size and washcoat stability. Careful analysis and monitoring are essential, not only during the research and development phase, but also during manufacturing to ensure product quality and consistency – plus troubleshooting any problems that may arise.
Monitoring the miniscule
Many factors can affect nanoparticle size, so regular and accurate measurement is key to achieving consistency.
For example, the Zetasizer uses dynamic light scattering (DLS) to measure even the smallest colloidal particles. Colloidal simply refers to extremely small particles, such as metal nanoparticles, suspended in a fluid phase.
So, you’ve got the tiniest particles suspended in your formula. How do you know if it will remain stable and perform well?
Stability is key
The stability of liquid dispersion washcoats is determined in part by the surface charge of the particles, with a high surface charge generally preventing aggregation. The zeta potential of a surface is a good indicator of surface charge. Zeta potential can be measured using an electrophoretic light scattering (ELS) instrument like the Zetasizer. Combining these measurements with knowledge of rheological properties helps to optimize dispersion conditions for a given suspension. The result? Improved stability and a finished washcoat with optimized performance.
Consistent, efficient, and future-ready
Quick and reliable measurement of nanoparticle size and predicted washcoat stability helps you create catalytic solutions that are more consistent, more effective, and more resource-efficient. So, whether you’re researching new catalysts to meet emerging challenges or aiming to optimize your current production processes, our analytical equipment and expert advice can support your needs.
Discover our full range of catalyst analysis solutions in our new brochure here.
Prefer to speak to an expert? Get in touch today to talk about your catalytic processes!
Join our Advanced Materials community on LinkedIn for more advanced materials research, news, and updates.
Further reading