2023 AIChE Annual Meeting

(698f) Investigation of Shaped Supports for Ruthenium-Based Catalysts on Ammonia Synthesis

Authors

Samuel Drummond, University of South Carolina
Jochen Lauterbach, University of South Carolina
Jennifer Naglic, University of South Carolina
Ammonia is necessary to produce synthetic fertilizer and has recently been suggested as a carbon-free energy carrier. Industrial ammonia production utilizes the Haber-Bosch method, which uses iron as an active metal and requires large energy input1. Ruthenium-based materials are considered a possible alternative. However, many investigations into various variables including supports, and morphology effects, are needed to improve these catalysts to compete with current industrial catalysts1,2. Utilizing different supports, such as praseodymium oxide may enhance the high dispersion of metal atoms and the number of active sites3. Moreover, synthesizing different shapes of nanoparticles with different faceting is one method to increase the catalytic activity of a catalyst2,3.

In this work, praseodymium oxide (PrxOy) nanowires and nanospheres were synthesized using the hydrothermal and precipitation methods, respectively. Ruthenium (Ru) with the different weight loadings were deposited onto the synthesized supports using simple impregnation method. Ru/PrxOy nanowires catalysts showed higher activity compared to nanospheres catalysts. Moreover, the activity of the Ru/PrxOy nanowires catalysts that were calcined at lower temperature, was higher because of different surface area and pore volume. Characterization using HRTEM, physisorption, chemisorption, CO-DRIFTS and XRD were used to investigate the differences between nanowires and nanospheres catalysts and the effects of morphology on ammonia synthesis rate. Well-known ammonia synthesis promoters, such as cesium and barium, were added to all the catalysts to increase the catalytic activity.

  1. Huang, J. et al. Inhibited hydrogen poisoning for enhanced activity of promoters-Ru/Sr2Ta2O7 nanowires for ammonia synthesis. J. Catal. 389, 556–565 (2020).
  2. Lin, B. et al. Morphology Effect of Ceria on the Catalytic Performances of Ru/CeO2 Catalysts for Ammonia Synthesis. Ind. Eng. Chem. Res. 57, 9127–9135 (2018).
  3. Chen, N., Younis, A., Chu, D. & Li, S. Controlled fabrication of Pr(OH)3 nanowires for enhanced photocatalytic activities. J. Rare Earths 37, 60–67 (2019).