FTIR Talk Letter (vol. 42)

Significance of the Topic

Reducing CO₂ emissions while enabling effective chemical analysis and materials characterization is critical for carbon-neutral strategies and quality control across industries. Techniques that integrate CO₂ capture and conversion, advanced infrared/Raman microscopy, and robust FTIR instrumentation support both environmental technologies and routine analytical workflows.

Objectives and Overview

This collection of studies and application notes focuses on three interrelated subjects:

• Design of dual-functional catalytic materials (DFMs) that capture low-concentration CO₂ and selectively hydrogenate it to CO under mild conditions.
• Configuration and performance of the AIRsight infrared/Raman microscope, which merges two spectroscopic methods in a single, compact unit.
• Key guidelines for interpreting FTIR spectra of saturated hydrocarbons (paraffins) such as polyethylene and polypropylene.

Methodology and Used Instrumentation

The DFM research employed stepwise impregnation to prepare Pt/M/Al₂O₃ catalysts (M = Na, K, Mg, Ca), followed by isothermal CO₂ capture from O₂-containing gas and H₂-driven reduction at 350 °C. In situ FTIR spectroscopy mapped surface intermediates, while STEM–EDX and CO-adsorption FTIR probed Pt nanoparticle structures.
Key instruments:

• AIRsight Infrared/Raman Microscope with interchangeable wide-field camera, 15× reflecting mirror, and 50×/100× Raman objectives, controlled via unified AMsolution software.
• Shimadzu IRSpirit-X FTIR spectrophotometer featuring pre-built macro routines, contaminant analysis, identification tests, and optional internal dehumidifier.

Main Results and Discussion

Pt-Na/Al₂O₃ exhibited superior CO₂ uptake and achieved 93 % CO selectivity versus <15 % for unpromoted Pt/Al₂O₃. STEM–EDX revealed Na-enriched shells around Pt cores, blocking CO adsorption sites and favoring desorption. In situ FTIR showed rapid CO₂ conversion to surface CO₂²⁻ and minimal further hydrogenation. The AIRsight microscope demonstrated sub-10 µm mapping accuracy in both IR and Raman modes without sample repositioning. FTIR analysis notes clarified how CH stretching (>3 000 cm⁻¹) and deformation/rocking bands distinguish paraffins, olefins, and aromatics, as well as polymer density and orientation via polarized measurements.

Benefits and Practical Applications

• DFMs enable compact, isothermal CO₂ capture-and-convert reactors for flue-gas streams.
• AIRsight streamlines micro‐FTIR and micro‐Raman workflows using a single footprint and software.
• Spectral interpretation guidelines reduce ambiguity in polymer QA/QC and material identification.

Future Trends and Opportunities

Emerging directions include non‐noble metal DFMs for selective CO and CH₄ production, direct air capture integration, automated high‐throughput IR/Raman screening, and advanced polarized mapping of polymer morphology. Coupling AI‐driven spectral analysis with compact instruments will accelerate on‐site process monitoring and materials research.

Conclusion

Integrating catalyst design, dual‐mode microscopy, and targeted spectral analysis offers powerful tools for environmental remediation and industrial analytics. Continued innovation in materials, optics, and software will drive more sustainable processes and faster, more reliable laboratory workflows.

References

1. M. S. Duyar et al., Appl. Catal. B Environ. 2015, 168–169, 370; F. Kosaka et al., Chem. Eng. J. 2022, 450, 138055.
2. L. F. Bobadilla et al., J. CO₂ Util. 2016, 14, 106.
3. L. Li et al., ACS Catal. 2022, 12, 2639.
4. L. Li et al., RSC Adv. 2023, 13, 2213.
5. L. Li et al., Chem. Eng. J. 2023, 477, 147199.
6. L. Li et al., Appl. Catal. B 2023, 339, 123151.