Question

I wondered how the morphology of the catalyst coating for fuel cells changes if it is dried either in a conventional oven (40 °C, 60°C, 80°C) or under an IR lamp. I am pretty certain that it changes, as Liu states:

If the formulation and preparation processes of the catalyst ink, as well as the coating process are fixed, the drying process of the ink film deposited on the substrate will determine the morphology and structure of the CL. There are several influencing factors that should be considered, e.g., the drying techniques, evaporation conditions, solvent physical properties, or solid concentration in the ink. [1]

However, this paper does not mention IR lamp drying explicitly.

[1] H. Liu, L. Ney, N. Zamel, X. Li, Applied Sciences 2022, 12, 3776.

Answer 1

The morphology of catalyst coatings for fuel cells will differ based on whether a conventional oven or an IR lamp is used for drying, with factors like drying rates and uniformity being key to the final structure. IR drying could potentially lead to quicker, less uniform drying, impacting the microstructure and performance. This underlines the broader significance of drying techniques on material properties as seen in various scientific applications.

Step-by-step explanation:

The morphology of the catalyst coating for fuel cells is significantly influenced by the drying technique employed. When dried in a conventional oven at 40°C, 60°C, or 80°C, solvent evaporation rate and uniformity of heating can result in varied particle distribution and inter-particle distances, thereby affecting the microstructure and performance of the coating. In contrast, IR lamp drying can provide more directed energy and potentially lead to a different evaporation rate, which could promote different morphological characteristics such as granularity, porosity, or surface roughness. While conventional oven drying is more gradual and uniform, the intense and localized heat of an IR lamp can rapidly increase the surface temperature, and thus might result in a less uniform but quicker drying process, which can impact the structure and functionality of the catalyst layer.

The impact of different drying techniques is evident in the varied nature of drying technologies. For example, when comparing to methods used for sample preparation in electron microscopy, wherein critical point drying with inert liquid carbon dioxide under pressure is performed to dehydrate specimens for SEM imaging or sputter-coating with metals is conducted to prevent charging, it is clear that the choice of technique can drastically alter the physical properties of the resultant material. This analogy illustrates the importance of the drying process and its influence on the physical characteristics of materials.