![]() This kind of systematic experimental layout is currently lacking in literature and therefore we mainly aim at filling this gap in the scientific literature. In this paper, we propose a systematic approach to apply IR thermography in operando studies. Significant examples of application of IR thermography as operando method include the study of exothermic reactions, the determination of the temperature rise in structured catalysts and the utilization in high-throughput experimentation. In particular, the installation of an appropriate IR transmitting window in a chemical reactor may be challenging. The main limitation to the development of the technique is related to the need of apposite reactors for this scope. Despite these evident advantages, the examples in literature of systems for the systematic use of IR thermography as an operando tool for the study of chemical reactions are scarce. Furthermore, the temperature measurement with devices placed inside the reactor (i.e., with thermocouples) inevitably interferes with the experiments. Therefore, the main advantage of IR thermography over other temperature measurements, such as thermocouples and pyrometers, is the high spatial resolution and contactless investigation of reactions. In particular, cooled IR cameras can achieve a very high sampling rate (above 100 Hz), while uncooled cameras, although cheaper, can record images with lower frequency. Commonly, an IR camera can provide several thousands of data points in its field view, with a measurement frequency of dozens of Hz. The main advantages of IR thermography are the relatively high resolution (each pixel fundamentally equals one temperature sensor) and high measurement rate which modern IR cameras offer. The methodology is widely employed outside the field of catalysis, for example for the determination of temperature in medical applications or for the analysis of heat losses in buildings. The measured radiation can be directly correlated with the temperature of the object, allowing for a precise and fast determination of the temperature. For thermal measurements the wavelength range of 3 micrometers to 15 micrometers is particularly interesting since a favorable radiance emission is detectable for these wavelength for thermal detection of earth surface emissions, everyday objects and relevant chemical reaction operation temperatures as discussed in the paper. Infrared radiation is typically in the wavelength range of 0.7 (near IR) to 1000 (far IR) micrometers. As a measurement technique, IR thermography operating principle is based on the detection of the IR radiation emitted by every object with a temperature above 0 K. ![]() A particular example of operando spectroscopic tool is infrared (IR) thermography. Operando spectroscopy aims at the determination of the variation of a wide range of catalyst properties during chemical reactions, including catalyst structure, oxidation state and reactivity. ![]() Over the last decades, operando spectroscopy-i.e., spectroscopy coupled simultaneously with measurements of catalytic activity-significantly improved the knowledge of catalytic systems in industrially relevant conditions. Furthermore, we present selected examples of catalytic reactions that can be monitored by IR thermography, showing the potential of the technology in revealing transient and steady state chemical phenomena. Here, we provide the guidelines to assemble a chemical reactor with an IR transmitting window through which the reaction can be studied with the infrared camera along with other best practice tips to achieve results. To achieve true operando investigation conditions, some dedicated equipment must be developed. This includes the need for a catalyst that provides a sufficiently high heat production (or absorption) rate. Secondly, we analyze the requirements towards the catalytic system to be directly observable by IR thermography. Firstly, the necessary properties of the catalytic reactor are described. This paper presents guidelines for the development of a reactor cell that can aid in the efficient exploitation of infrared thermography for the investigation of catalytic and other surface reactions. A particularly interesting application of this technology is in the field of catalysis, where the method can provide new insights into dynamic surface reactions. Infrared (IR) thermography is a powerful tool to measure temperature with high space and time resolution.
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