[{"date_updated":"2026-02-17T16:14:45Z","date_created":"2026-02-07T16:02:06Z","author":[{"first_name":"Sarah","last_name":"Neumann","full_name":"Neumann, Sarah"},{"first_name":"Torsten","last_name":"Gutmann","full_name":"Gutmann, Torsten","id":"118165"},{"first_name":"Gerd","full_name":"Buntkowsky, Gerd","last_name":"Buntkowsky"},{"last_name":"Paul","full_name":"Paul, Stephen","first_name":"Stephen"},{"full_name":"Thiele, Greg","last_name":"Thiele","first_name":"Greg"},{"last_name":"Sievers","full_name":"Sievers, Heiko","first_name":"Heiko"},{"first_name":"Marcus","full_name":"Bäumer, Marcus","last_name":"Bäumer"},{"last_name":"Kunz","full_name":"Kunz, Sebastian","first_name":"Sebastian"}],"volume":377,"title":"Insights into the reaction mechanism and particle size effects of CO oxidation over supported Pt nanoparticle catalysts","doi":"10.1016/j.jcat.2019.07.049","year":"2019","citation":{"bibtex":"@article{Neumann_Gutmann_Buntkowsky_Paul_Thiele_Sievers_Bäumer_Kunz_2019, title={Insights into the reaction mechanism and particle size effects of CO oxidation over supported Pt nanoparticle catalysts}, volume={377}, DOI={<a href=\"https://doi.org/10.1016/j.jcat.2019.07.049\">10.1016/j.jcat.2019.07.049</a>}, journal={Journal of Catalysis}, author={Neumann, Sarah and Gutmann, Torsten and Buntkowsky, Gerd and Paul, Stephen and Thiele, Greg and Sievers, Heiko and Bäumer, Marcus and Kunz, Sebastian}, year={2019}, pages={662–672} }","mla":"Neumann, Sarah, et al. “Insights into the Reaction Mechanism and Particle Size Effects of CO Oxidation over Supported Pt Nanoparticle Catalysts.” <i>Journal of Catalysis</i>, vol. 377, 2019, pp. 662–672, doi:<a href=\"https://doi.org/10.1016/j.jcat.2019.07.049\">10.1016/j.jcat.2019.07.049</a>.","short":"S. Neumann, T. Gutmann, G. Buntkowsky, S. Paul, G. Thiele, H. Sievers, M. Bäumer, S. Kunz, Journal of Catalysis 377 (2019) 662–672.","apa":"Neumann, S., Gutmann, T., Buntkowsky, G., Paul, S., Thiele, G., Sievers, H., Bäumer, M., &#38; Kunz, S. (2019). Insights into the reaction mechanism and particle size effects of CO oxidation over supported Pt nanoparticle catalysts. <i>Journal of Catalysis</i>, <i>377</i>, 662–672. <a href=\"https://doi.org/10.1016/j.jcat.2019.07.049\">https://doi.org/10.1016/j.jcat.2019.07.049</a>","ama":"Neumann S, Gutmann T, Buntkowsky G, et al. Insights into the reaction mechanism and particle size effects of CO oxidation over supported Pt nanoparticle catalysts. <i>Journal of Catalysis</i>. 2019;377:662–672. doi:<a href=\"https://doi.org/10.1016/j.jcat.2019.07.049\">10.1016/j.jcat.2019.07.049</a>","chicago":"Neumann, Sarah, Torsten Gutmann, Gerd Buntkowsky, Stephen Paul, Greg Thiele, Heiko Sievers, Marcus Bäumer, and Sebastian Kunz. “Insights into the Reaction Mechanism and Particle Size Effects of CO Oxidation over Supported Pt Nanoparticle Catalysts.” <i>Journal of Catalysis</i> 377 (2019): 662–672. <a href=\"https://doi.org/10.1016/j.jcat.2019.07.049\">https://doi.org/10.1016/j.jcat.2019.07.049</a>.","ieee":"S. Neumann <i>et al.</i>, “Insights into the reaction mechanism and particle size effects of CO oxidation over supported Pt nanoparticle catalysts,” <i>Journal of Catalysis</i>, vol. 377, pp. 662–672, 2019, doi: <a href=\"https://doi.org/10.1016/j.jcat.2019.07.049\">10.1016/j.jcat.2019.07.049</a>."},"page":"662–672","intvolume":"       377","_id":"64018","user_id":"100715","keyword":["Solid state NMR","“Surfactant-free” platinum nanoparticles","CO oxidation","Particle size effect","Structure sensitivity"],"language":[{"iso":"eng"}],"extern":"1","type":"journal_article","publication":"Journal of Catalysis","abstract":[{"text":"CO oxidation is an extensively studied reaction in heterogeneous catalysis due to its seeming simplicity and its great importance for emission control. However, the role of particle size and more specifically structure sensitivity in this reaction is still controversial. In the present study, colloidal “surfactant-free” Pt nanoparticles (NPs) in a size regime of 1–4 nm with narrow size distribution and control over particle size were synthesized and subsequently supported on Al2O3 to prepare model catalysts. CO oxidation was performed using Pt NPs catalysts with particles sizes of 1, 2, 3, and 4 nm at different reaction temperatures. It is shown that the reaction exhibits a particle size effect that depends strongly on the reaction conditions. At 170 °C, the reaction seems to proceed within the same kinetic regime for all particle sizes, but the surface normalized activity depends strongly on the particle size, with maximum activity for nanoparticles 2 nm in diameter. A temperature increase to 200 °C leads to a change of the kinetic regime that depends on the particle size. For Pt NPs 1 nm in diameter a reaction order of 1 for O2 was observed, indicating that O2 adsorbs molecularly and dissociates in a following step, which represents the generally accepted mechanism on Pt surfaces. The reaction order of −1 for CO demonstrates that the surface is saturated with CO under reaction conditions. With increasing particle size, the reaction orders of O2 and CO change. For particles 2 nm in size, an increase in temperature also results in reaction orders of 1 for O2 and −1 for CO; NPs of 3 and 4 nm, even at higher temperatures, show no clear kinetic behavior that can be explained by a single reaction mechanism. Instead, the Boudouard reaction between two adjacent adsorbed CO molecules was identified as an important additional reaction pathway that occurs preferentially on large particles and causes more complex kinetics.","lang":"eng"}],"status":"public"},{"type":"journal_article","publication":"Catalysis Science & Technology","abstract":[{"text":"A series of 1 and 2 nm sized platinum nanoparticles (Pt-NPs) deposited on different support materials, namely, gamma-alumina (gamma-Al2O3), titanium dioxide (TiO2), silicon dioxide (SiO2) and fumed silica are investigated by solid-state NMR and dynamic nuclear polarization enhanced NMR spectroscopy (DNP). DNP signal enhancement factors up to 170 enable gaining deeper insight into the surface chemistry of Pt-NPs. Carbon monoxide is used as a probe molecule to analyze the adsorption process and the surface chemistry on the supported Pt-NPs. The studied systems show significant catalytic activity in carbon monoxide oxidation on their surface at room temperature. The underlying catalytic mechanism is the water-gas shift reaction. In the case of alumina as the support the produced CO2 reacts with the surface to form carbonate, which is revealed by solid-state NMR. A similar carbonate formation is also observed when physical mixtures of neat alumina with silica, fumed silica and titania supported Pt-NPs are studied.","lang":"eng"}],"status":"public","_id":"63991","user_id":"100715","keyword":["Chemistry","gamma-alumina","hydrogenation","silica","c-13","interactions","metal-catalysts","particle-size","platinum nanoparticles","sites","surface","water-gas shift"],"extern":"1","language":[{"iso":"eng"}],"publication_identifier":{"issn":["2044-4753"]},"issue":"14","year":"2019","citation":{"bibtex":"@article{Klimavicius_Neumann_Kunz_Gutmann_Buntkowsky_2019, title={Room temperature CO oxidation catalysed by supported Pt nanoparticles revealed by solid-state NMR and DNP spectroscopy}, volume={9}, DOI={<a href=\"https://doi.org/10.1039/c9cy00684b\">10.1039/c9cy00684b</a>}, number={14}, journal={Catalysis Science &#38; Technology}, author={Klimavicius, V. and Neumann, S. and Kunz, S. and Gutmann, Torsten and Buntkowsky, G.}, year={2019}, pages={3743–3752} }","mla":"Klimavicius, V., et al. “Room Temperature CO Oxidation Catalysed by Supported Pt Nanoparticles Revealed by Solid-State NMR and DNP Spectroscopy.” <i>Catalysis Science &#38; Technology</i>, vol. 9, no. 14, 2019, pp. 3743–3752, doi:<a href=\"https://doi.org/10.1039/c9cy00684b\">10.1039/c9cy00684b</a>.","short":"V. Klimavicius, S. Neumann, S. Kunz, T. Gutmann, G. Buntkowsky, Catalysis Science &#38; Technology 9 (2019) 3743–3752.","apa":"Klimavicius, V., Neumann, S., Kunz, S., Gutmann, T., &#38; Buntkowsky, G. (2019). Room temperature CO oxidation catalysed by supported Pt nanoparticles revealed by solid-state NMR and DNP spectroscopy. <i>Catalysis Science &#38; Technology</i>, <i>9</i>(14), 3743–3752. <a href=\"https://doi.org/10.1039/c9cy00684b\">https://doi.org/10.1039/c9cy00684b</a>","ama":"Klimavicius V, Neumann S, Kunz S, Gutmann T, Buntkowsky G. Room temperature CO oxidation catalysed by supported Pt nanoparticles revealed by solid-state NMR and DNP spectroscopy. <i>Catalysis Science &#38; Technology</i>. 2019;9(14):3743–3752. doi:<a href=\"https://doi.org/10.1039/c9cy00684b\">10.1039/c9cy00684b</a>","chicago":"Klimavicius, V., S. Neumann, S. Kunz, Torsten Gutmann, and G. Buntkowsky. “Room Temperature CO Oxidation Catalysed by Supported Pt Nanoparticles Revealed by Solid-State NMR and DNP Spectroscopy.” <i>Catalysis Science &#38; Technology</i> 9, no. 14 (2019): 3743–3752. <a href=\"https://doi.org/10.1039/c9cy00684b\">https://doi.org/10.1039/c9cy00684b</a>.","ieee":"V. Klimavicius, S. Neumann, S. Kunz, T. Gutmann, and G. Buntkowsky, “Room temperature CO oxidation catalysed by supported Pt nanoparticles revealed by solid-state NMR and DNP spectroscopy,” <i>Catalysis Science &#38; Technology</i>, vol. 9, no. 14, pp. 3743–3752, 2019, doi: <a href=\"https://doi.org/10.1039/c9cy00684b\">10.1039/c9cy00684b</a>."},"page":"3743–3752","intvolume":"         9","date_updated":"2026-02-17T16:16:33Z","date_created":"2026-02-07T15:47:21Z","author":[{"last_name":"Klimavicius","full_name":"Klimavicius, V.","first_name":"V."},{"first_name":"S.","last_name":"Neumann","full_name":"Neumann, S."},{"last_name":"Kunz","full_name":"Kunz, S.","first_name":"S."},{"first_name":"Torsten","id":"118165","full_name":"Gutmann, Torsten","last_name":"Gutmann"},{"last_name":"Buntkowsky","full_name":"Buntkowsky, G.","first_name":"G."}],"volume":9,"title":"Room temperature CO oxidation catalysed by supported Pt nanoparticles revealed by solid-state NMR and DNP spectroscopy","doi":"10.1039/c9cy00684b"},{"type":"journal_article","publication":"Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on","abstract":[{"text":"(K,Na)NbO3 ceramics have attracted much attention as lead-free piezoelectric materials with high piezoelectric properties. High-quality (K,Na)NbO3 ceramics can be sintered using KNbO3 and NaNbO3 powders synthesized by a hydrothermal method. In this study, to enhance the quality factor of the ceramics, high-power ultrasonic irradiation was employed during the hydrothermal method, which led to a reduction in the particle size of the resultant powders.","lang":"eng"}],"status":"public","_id":"9878","user_id":"55222","department":[{"_id":"151"}],"keyword":["Q-factor","ceramics","crystal growth from solution","particle size","piezoelectric materials","potassium compounds","powders","sintering","sodium compounds","ultrasonic effects","(K0.48Na0.52)NbO3","KNbO3 powders","NaNbO3 powders","high-power ultrasonic irradiation","lead-free piezoelectric materials","lead-free piezoelectric powders","particle size reduction","piezoelectric properties","quality factor","sintered (K0.48Na0.52)NbO3 ceramics","sintering","ultrasonic-assisted hydrothermal method","Acoustics","Ceramics","Lead","Piezoelectric materials","Powders","Radiation effects","Transducers"],"language":[{"iso":"eng"}],"publication_identifier":{"issn":["0885-3010"]},"quality_controlled":"1","issue":"2","year":"2014","citation":{"apa":"Isobe, G., Maeda, T., Bornmann, P., Hemsel, T., &#38; Morita, T. (2014). Synthesis of lead-free piezoelectric powders by ultrasonic-assisted hydrothermal method and properties of sintered (K0.48Na0.52)NBO3 ceramics. <i>Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions On</i>, <i>61</i>(2), 225–230. <a href=\"https://doi.org/10.1109/TUFFC.2014.6722608\">https://doi.org/10.1109/TUFFC.2014.6722608</a>","mla":"Isobe, G., et al. “Synthesis of Lead-Free Piezoelectric Powders by Ultrasonic-Assisted Hydrothermal Method and Properties of Sintered (K0.48Na0.52)NBO3 Ceramics.” <i>Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions On</i>, vol. 61, no. 2, 2014, pp. 225–30, doi:<a href=\"https://doi.org/10.1109/TUFFC.2014.6722608\">10.1109/TUFFC.2014.6722608</a>.","bibtex":"@article{Isobe_Maeda_Bornmann_Hemsel_Morita_2014, title={Synthesis of lead-free piezoelectric powders by ultrasonic-assisted hydrothermal method and properties of sintered (K0.48Na0.52)NBO3 ceramics}, volume={61}, DOI={<a href=\"https://doi.org/10.1109/TUFFC.2014.6722608\">10.1109/TUFFC.2014.6722608</a>}, number={2}, journal={Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on}, author={Isobe, G. and Maeda, Takafumi and Bornmann, Peter and Hemsel, Tobias and Morita, Takeshi}, year={2014}, pages={225–230} }","short":"G. Isobe, T. Maeda, P. Bornmann, T. Hemsel, T. Morita, Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions On 61 (2014) 225–230.","ama":"Isobe G, Maeda T, Bornmann P, Hemsel T, Morita T. Synthesis of lead-free piezoelectric powders by ultrasonic-assisted hydrothermal method and properties of sintered (K0.48Na0.52)NBO3 ceramics. <i>Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on</i>. 2014;61(2):225-230. doi:<a href=\"https://doi.org/10.1109/TUFFC.2014.6722608\">10.1109/TUFFC.2014.6722608</a>","chicago":"Isobe, G., Takafumi Maeda, Peter Bornmann, Tobias Hemsel, and Takeshi Morita. “Synthesis of Lead-Free Piezoelectric Powders by Ultrasonic-Assisted Hydrothermal Method and Properties of Sintered (K0.48Na0.52)NBO3 Ceramics.” <i>Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions On</i> 61, no. 2 (2014): 225–30. <a href=\"https://doi.org/10.1109/TUFFC.2014.6722608\">https://doi.org/10.1109/TUFFC.2014.6722608</a>.","ieee":"G. Isobe, T. Maeda, P. Bornmann, T. Hemsel, and T. Morita, “Synthesis of lead-free piezoelectric powders by ultrasonic-assisted hydrothermal method and properties of sintered (K0.48Na0.52)NBO3 ceramics,” <i>Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on</i>, vol. 61, no. 2, pp. 225–230, 2014."},"intvolume":"        61","page":"225-230","date_updated":"2019-09-16T10:53:17Z","date_created":"2019-05-20T13:10:14Z","author":[{"first_name":"G.","last_name":"Isobe","full_name":"Isobe, G."},{"last_name":"Maeda","full_name":"Maeda, Takafumi","first_name":"Takafumi"},{"first_name":"Peter","last_name":"Bornmann","full_name":"Bornmann, Peter"},{"first_name":"Tobias","full_name":"Hemsel, Tobias","id":"210","last_name":"Hemsel"},{"last_name":"Morita","full_name":"Morita, Takeshi","first_name":"Takeshi"}],"volume":61,"title":"Synthesis of lead-free piezoelectric powders by ultrasonic-assisted hydrothermal method and properties of sintered (K0.48Na0.52)NBO3 ceramics","doi":"10.1109/TUFFC.2014.6722608"}]