Oxidation of Carbon Monoxide by Pt-Doped Titania-Based Photocatalysts

Research Team

Sean Elliot

Chemical Engineering

Josiah Warrington

Chemical Engineering

Mentor: Dr. Catherine Almquist

Chemical, Paper, and Biomedical Engineering

Abstract/Introduction

The purpose of this project is to investigate the role of Pt loading and Pt oxidation state on Pt/TiO2 photocatalysts for the photocatalytic oxidation of carbon monoxide (CO). CO is toxic, and high concentrations can be fatal. In confined spaces, such as in mobile vehicles and vessels (e.g. submarines, airplanes, RVs, etc.), CO can accumulate and must be mitigated so that it does not build up to toxic levels. To help address these issues, this project aims to explore the mechanism of photocatalysis through characterization of both oxidized and reduced Pt/TiO2 catalysts in an effort to link catalyst properties to overall effectiveness as measured by conversion of CO to less dangerous CO2.

Results and Discussion

Pt loading effects the percent conversion of oxidizing CO without the LEDs on. However, with the LEDs on the effect of the amount Pt loading on CO conversion is not able to be determined at the high conversion state of all catalysts. However, it can be seen that any Pt doping does have a significant effect on catalyst activity. All tests were run with 365 nm LEDs, a flow rate of 250 ccpm ± 2 ccpm, [CO] = 300 ppm ± 30 ppm, and a residence time = 60 s ± 2s.

The UV-Vis results show an increase in light absorption at greater Pt loading. The band gap slope is similar for all Pt loadings, including 0 wt%. Photocatalytic activity is likely caused instead by greater activation of the oxygen. For 1 wt% Pt/TiO2-R, as the wavelengths increased, a decrease in percent conversion can be seen. All tests were run at [CO] = 300 ppm ± 20 ppm and at room temperature.

Conclusions and Future Study

→ Reduced photocatalysts have a higher conversion percentage with both the LEDs on and off compared to the oxidized versions of Pt/TiO2.

→ Wavelength has an apparent effect on the conversion percentage for oxidizing CO.

-The most effective tested wavelength was 365 nm followed by the 395 nm LEDs.

→ At tested conditions, Pt loading has little effect on the conversion percentage when the LEDs are on.

-Pt enhanced light absorption of the catalyst in the visible light region.

-Future work will investigate Pt loading with faster residence times using smaller reactors.

→ Tests on the effect of humidity all showed near complete conversion of CO to CO2 at test conditions; future tests at lower residence times are required to effectively examine the effect of humidity.

The following is an image of the poster presented at the 2026 Undergraduate Research Forum

An image of the URF poster. It includes sections for project background, catalyst synthesis, test system, characterization, catalytic performance, conclusions and future work, acknowledgements, and references.

Acknowledgements

Graduate Students Brooke Moon, Anna Kauffman, David Metzger, Gabe Gabrovsek
Naval Surface Warfare Center (NSWC) Dahlgren Division (DD); Grant Number: N00178-25-1-0014
Center for Advanced Microscopy and Imaging (CAMI) at Miami University
Miami University Instrumentation Lab
Miami University Mechanical Engineering Machine Shop
Ohio State University Surface Analysis Laboratory (SAL)

References

Ovcharov, Mykhailo & Granchak, V.. (2019). Photocatalytic Activation of Carbon Monoxide on Semiconductors and Derived Nanocomposites: Basic Principles and Mechanisms: A Review. Theoretical and Experimental Chemistry. 55. https://doi.org/10.1007/s11237-019-09608-3
Ivanova, E., Mihaylov, M., Thibault-Starzyk, F., Daturi, M., Hadjiivanov, K. (2007). FTIR spectroscopy study of CO and NO adsorption and co-adsorption on Pt/TiO2.Journal of Molecular Catalysis A: Chemical, 274, (1–2), pp. 179-184. https://doi.org/10.1016/j.molcata.2007.05.006
Kim, G.J.,Kwon, D.W., Hong, S.C. (2016). Effect of Pt Particle Size and Valence State on the Performance of Pt/TiO2 Catalysts for CO Oxidation at Room Temperature. The Journal of Physical Chemistry C, 120(32), pp. 17996-18004. https://doi.org/10.1021/acs.jpcc.6b02945
Irfan, F., Tanveer, M.U., Moiz, M.A. et al. (2022). TiO2 as an effective photocatalyst mechanisms, applications, and dopants: a review. European Physical Journal B, 95, 184. https://doi.org/10.1140/epjb/s10051-022-00440-8
Shen, S., Wang, X., Ding, Q., Jin, S., Feng, Z., Li, C. (2014). Effect of Pt cocatalyst in Pt/TiO2 studied by in situ FTIR of CO adsorption. Chinese Journal of Catalysis, 35(11), pp. 1900-1906. https://doi.org/10.1016/S1872-2067(14)60172-
Sharma, G., Sahle-Demessie, E., Almquist, C.B. (2025). An Investigation of WO3/V2O5/TiO2 Catalysts: Effects of WO3 on Morphology, Thermal Stability, and Activity for the Catalytic Oxidation of Dimethyl Sulfide. Molecules, 30(11):2436. https://doi.org/10.3390/molecules30112436
McMahon, K., Launico, M.V. (2025). Carbon Monoxide Toxicity. Available from: https://www.ncbi.nlm.nih.gov/books/NBK430740/
M.-J. Choi, H. Park, M. H. Engelhard, D. Li, P. V. Sushko, and Y. Du, “Reevaluation of XPS Pt 4f peak fitting: Ti 3s plasmon peak interference and Pt metallic peak asymmetry in Pt@TiO2 system,” Journal of Vacuum Science & Technology A, vol. 42, no. 6, p. 063209, Dec. 2024, doi: 10.1116/6.0003973. https://doi.org/10.1116/6.0003973
B. Ohtani, Chapter 10 - Photocatalysis by inorganic solid materials: Revisiting its definition, concepts, and experimental procedures, Editor(s): Rudi van Eldik, Grażyna Stochel, Advances in Inorganic Chemistry, Academic Press, Volume 63, 2011, Pages 395-430, ISSN 0898-8838, ISBN 9780123859044, https://doi.org/10.1016/B978-0-12-385904-4.00001-9.

NACE Career Readiness Competencies

Career + Self Development: This project allowed students to gain a greater awareness of areas needing further development and filled in gaps career-applicable training and education.

Technology: Multiple characterization instruments, gas plumbing systems, methods of measuring flow rates were effectively used.

Professionalism: Weekly goals and expectations were set throughout the project, encouraging timely and high-quality work.

Research Compliance Protocols

All laboratory safety and MSDS procedures were followed thoroughly. Researcher backgrounds and competencies are inline with the Naval Surface Warfare Center grant guidelines.

Page updated

Report abuse