CO2 Reduction Gas Products Analysis Using the Agilent 990 Micro GC

Significance of the Topic

Conversion of CO2 into small hydrocarbons and chemicals provides a sustainable route to reduce greenhouse gas levels and produce value-added products. Precise monitoring of reaction products is essential for catalyst evaluation and process optimization.

Study Objectives and Overview

The main goal of this study is to demonstrate the capabilities of the Agilent 990 Micro GC in analyzing CO2 reduction products (H2, CO, CH4, C2H6, C2H4). Two chromatographic channels are evaluated to cover the full range of light gases produced during CO2 reduction processes.

Instrumentation Used

• Agilent 990 Micro GC
• Channel 1: 10 m Agilent CP-Molsieve 5Å column with 5 m precolumn, equipped with backflush and retention time stability (RTS) options, operated with helium carrier gas
• Channel 2: 10 m Agilent CP-PoraPLOT U straight column, operated with helium carrier gas

Methodology and Experimental Setup

• Standard gas mixture containing H2, CH4, CO, C2H4, C2H6, and CO2 balance
• Injector temperatures: 60 °C for Channel 1, 50 °C for Channel 2
• Column temperatures: 60 °C for CP-Molsieve, 40 °C for CP-PoraPLOT U
• Column pressures: 180 kPa (Channel 1), 100 kPa (Channel 2)
• Injection times: 100 ms (Channel 1), 20 ms (Channel 2)

Main Results and Discussion

The CP-Molsieve channel achieved baseline separation of H2, CH4, and CO within 2.5 minutes. The CP-PoraPLOT U channel separated CH4, CO2, C2H4, and C2H6 within 2 minutes. Ten consecutive runs showed excellent repeatability with retention time relative standard deviation (RSD) below 1% and peak area RSD below 3% for all components.

Benefits and Practical Applications

• Rapid, reliable analysis of CO2 reduction products enables real-time process control.
• High repeatability supports routine catalyst screening and performance evaluation.
• Compact micro GC design allows deployment in laboratory and field settings.

Future Trends and Potential Applications

• Integration with online reactors for continuous monitoring of CO2 conversion.
• Expansion to additional product species such as formic acid and methanol with tailored columns.
• Coupling with mass spectrometric detectors for enhanced identification in complex mixtures.

Conclusion

The Agilent 990 Micro GC with Molsieve 5Å and PoraPLOT U channels provides a fast, precise, and robust solution for quantifying light hydrocarbons and CO produced in CO2 reduction. Its high separation efficiency and repeatability make it suitable for catalyst evaluation and process optimization, advancing CO2 utilization research.

References

• van Loon R. Permanent Gas Analysis – Separation of Helium, Neon and Hydrogen on a MolSieve 5A column using the Agilent 490 Micro GC. Agilent Technologies Application Note, 5990-8527EN, 2011.
• van Loon R. C1–C3 Hydrocarbon Analysis Using the Agilent 490 Micro GC – Separation Characteristics for PoraPLOT U and PoraPLOT Q Column Channels. Agilent Technologies Application Note, 5990-9165EN, 2011.