In this study, optical calorimetry is introduced for the investigation of activation procedures and catalyst composition on the catalytic carbon monoxide (CO) oxidation at ambient conditions. In addition, temperature-dependent measurements are presented using a novel temperature-controlled InfraSORP technology. Temperature-dependent measurements as well as the influence of different activation conditions were carried out using a commercially available copper manganese oxide catalyst (CARULITE 300). The influence of the catalyst composition was investigated on copper manganese mixed oxides synthesized by a flame spray pyrolysis process. By comparing the results of optical calorimetry to in situ catalytic measurements, a good linear correlation of the optical signal and the CO conversion is demonstrated. In contrast to standard catalysis, the optical calorimetry allows a rapid screening (only 5–10 min per sample) with even a minimal amount of catalyst sample prior to testing any final candidates for respiratory filter materials in real applications.

A systematic investigation of copper‐ and manganese‐carboxylate precursors derived from various organic acids (arylcarboxylate, alkylcarboxyate) and their transformation into copper manganese nanoparticles via flame spray pyrolysis (FSP) reveals significant impact on their physical and catalytic properties. A sodium‐free protocol is essential to achieve high purity copper(II) and manganese(II) 2‐ethylhexanoates, benzoates, 1‐naphthenates and 9‐ anthracenates as revealed by infrared spectroscopy (IR) and thermogravimetry (TG). In order to exclude the influence of other parameters, the FSP syntheses were carried out using fixed air/feed ratio. Especially aromatic precursors lead to smaller nanoparticles with high surface areas up to 180 m2g−1 and that these also have a higher carbon content. TPR investigations have shown that the copper and manganese atoms are in close contact with each other, which significantly reduces their reduction temperature. In catalytic CO oxidation, all samples synthesized from organometallic precursors have shown higher CO conversions at room temperature under dry conditions and improved long‐term stability under wet conditions compared to a commercial reference. The activity depends mainly on the Cu : Mn ratio and the specific surface area. At room temperature under dry conditions, catalytic CO conversion exceeding 80 % could be achieved. A decreased deactivation rate under humid conditions could be related to an increased carbon content of the nanocatalysts. By optimization of the synthesis parameters and the use of pure precursors, it was possible to show that flame spray pyrolysis is an efficient, scalable and single‐stage synthesis method for Hopcalite nanoparticles, which additionally provides more active catalysts than those from alternative synthesis methods.