In Situ Luminescence Thermometry to Locally Measure Temperature Gradients during Catalytic Reactions Journal Article
In: ACS Catalysis, vol. 8, no. 3, pp. 2397-2401, 2018.
Thimo Jacobs
One of the largest CO2 emitting industries is the metallurgical industry, including steel producers. Tata Steel recently developed a new process, called HIsarna, in which the CO2 emissions are reduced by at least 20%. [1] The works arising gases (WAGs) of the HIsarna process are CO2-rich (almost 70% CO2) and high in temperature (up to 1500°C). The overall project aims to develop the necessary thermo- and electrocatalysts to convert these WAGs into valuable chemical building blocks, using the high temperature of the HIsarna WAGs.
Within this project, analytical tools are required to monitor the CO2 conversion. By designing bifunctional electrodes, containing the catalyst, shell-isolated nanoparticles (SHINs) and temperature probes, local adsorbates and heat effects can be studied. These local sensors enable a direct comparison between the electrochemical and thermochemical conversion routes, where the mechanistic pathways of the CO2 conversion can be investigated using the SHINs. Since the electrochemical conversion is performed at temperatures of up to 200°C, local heat effects can play a crucial role. Thermometry will be used to study these local heat effects, for example the effect of the current density on the local temperature.
The combination of shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) and luminescence thermometry for operando monitoring of catalysis has already been studied within our group, but was limited to temperatures of ~ 350°C. [2] The main challenge for this project is therefore to increase the thermal stability of both the SHINs and temperature probes, since the second step in the thermocatalytic CO2 conversion (i.e., CH4 to aromatics; dehydroaromatization) requires temperatures of up to 800°C. The deployment of these analytical techniques at high temperatures enables a more detailed study of the CO2 conversion and can contribute to an even further decrease in CO2 emissions from the steel industry.
[1] Keys, A., van Hout, M., Daniëls, B., Decarbonisation options for the Dutch Steel Industry, PBL Netherlands Environmental Assessment Agency & ECN part of TNO, The Hague (2019).
[2] Hartman, T., Geitenbeek, R.G., Whiting, G.T., Weckhuysen, B.M., Operando monitoring of temperature and active species at the single catalyst particle level. Nat. Catal. 2, 986–996 (2019).