Poster Session Details
Date: April 16th, 2025
Time: Following the Seminar (approx. 4:00 PM – 5:00 PM)
Location: Earth and Space Sciences, Room 145
Poster #1: Tracking Chemical Evolution of Cr Ions in Molten LiCl-KCl Salts via In Situ X-ray Absorption Spectroscopy
Presenter: Yuxiang Peng
Abstract: LiCl-KCl eutectic molten salt is widely used in concentrated solar power, molten salt reactors, pyrochemical reprocessing, and electrorefining. However, chromium in the containment alloys can cause undesirable corrosion and material degradation with LiCl-KCl. The corrosion mechanism remains unclear, partly due to the unknown evolution of Cr species in molten salt. In this work, the chemical stabilities of CrCl2, CrCl3, and Cr2O3 in LiCl-KCl eutectic molten salt at elevated temperatures were investigated with in situ X-ray absorption spectroscopy. Results indicated that CrCl3 and Cr2O3 were stable while CrCl2 was oxidized by impurities. The chemical evolution of Cr with NiCl2 in LiCl-KCl molten salt at high temperatures was also examined, revealing Cr initially reacted with Ni2+ forming as Cr2+, and further oxidized by impurities. These findings are essential for understanding the corrosion mechanism of Cr in molten salt and further improving the stability of containment alloys in molten salt applications.
Poster #2: Investigating the Redox Kinetics of Copper Oxide for Thermal Energy Storage Using In Situ Spectroscopic Imaging and Nano-tomography
Presenter: Chirag Saharan
Abstract: The transition to sustainable energy systems necessitates the development of advanced thermal energy storage (TES) materials with high efficiency and durability. Copper oxide (CuO), a cost-effective metal oxide, exhibits favorable redox properties for TES applications but faces limitations due to sintering and degradation under cyclic high-temperature conditions. In this study, we investigate the redox-driven phase transformation between CuO (Cu²⁺) and Cu₂O (Cu⁺) in copper oxide microparticles subjected to thermal cycling between 850°C and 1040°C. Thermogravimetric analysis (TGA) confirmed oxygen release during CuO reduction and subsequent partial reoxidation. To capture the morphological and chemical evolution during redox cycling, we employed in situ full-field X-ray nano-tomography and two-dimensional X-ray absorption near edge structure (2D XANES) imaging at the FXI (18-ID) beamline of NSLS-II, Brookhaven National Laboratory. The phase transition was corroborated by distinct shifts in the white line position in XANES spectra (8986 eV for CuO and 8982 eV for Cu₂O), indicating reversible redox activity. Tomographic reconstructions revealed significant morphological changes, including particle sintering, porosity loss, and surface smoothing at elevated temperatures. These findings provide critical insight into the redox kinetics, microstructural stability, and energy retention capacity of copper oxide in TES systems.
Poster #3: Impact of EuCl3 on the Morphological Evolution of Ni-20Cr Alloys in LiCl-KCl Eutectic Molten Salt Environments
Presenter: Ankita Mohanty
Abstract: Recent advancements have revitalized interest in molten salts as heat transfer fluids and reaction media in energy systems such as molten salt reactors (MSRs), concentrating solar power plants, and batteries. Structural alloys exposed to molten salts undergo morphological changes that might result in degradation. MSRs will expose materials to molten salt containing numerous fission products that may act as oxidants, further accelerating the corrosion of the alloys. One such corrosive species is EuCl3. We examined the impact of added EuCl3 on the morphological and chemical evolution of Ni-20Cr alloy in molten LiCl-KCl eutectic using a multimodal characterization approach combining synchrotron X-ray nano-tomography, X-ray absorption spectroscopy and transmission electron microscopy. This helped us understand the corrosion mechanisms occurring at the metal-salt interface in the presence of EuCl3 over time, revealing more spatially-resolved details at the sub-micron level. A detailed observation of morphological transformations in Ni-20Cr alloys over varying temperatures is discussed.
Poster #4: Development of ceria-supported metal-oxide (MOx/CeO2) catalysts via a one-pot chemical vapor deposition (OP-CVD) technique: Structure and reverse water gas shift reaction study
Presenter: Amol Pophali
Abstract: Current synthesis techniques for metal oxide (MOx)-supported catalysts have certain limitations of undesired target loading, ineffective dispersion of active species over the surface, uncontrolled particle size of active species, and complicated synthesis steps. We developed a one-pot chemical vapor deposition (OP-CVD) methodology; by using which a solid metal precursor forms a vapor in a controlled condition and gets supported over the surrounding matrix. The theoretical stability followed by experimental validation using TGA is crucial for selecting the metal precursors. Three simple steps, viz. premixing, dispersion, and rapid fixation by calcination, are involved in the catalyst development via the OP-CVD approach. This study solely focused on the synthesis of 3d transition MOx over ceria support. The physicochemical characterizations of the prepared catalysts were performed by XRD, ICP-OES, SEM-EDX, CO pulse chemisorption, XANES, and EXAFS analyses to understand the crystal structure of involved species, target metal loading, dispersion, and particle size to prove the feasibility and viability of OP-CVD. The prepared catalysts were further tested for reverse water gas shift (RWGS) reaction to link their structural information with activity. The RWGS reaction data showed that the CO activity and CO selectivity were metal – and metal precursor-dependent. Higher CO activity of > 0.1 mol/h g-cat was observed for Cu and Co-based catalysts, with CO selectivity of ∼100 %. This study provides an opportunity to produce efficient supported catalysts in a convenient way, providing effective catalytic activity.
Poster #5: Precision Surface Synthesis of Sub-nm Iridium Nanoparticles on Nitrides: Tuned Metal-Support Interactions for Enhanced OER Catalysis
Presenter: Wenhao Liu
Abstract: The development of efficient oxygen evolution reaction (OER) catalysts is critical for electrochemical water splitting technologies, while it is challenging to develop stability and performance in acidic environments. In this study, we synthesized sub-nanometer Iridium (Ir) nanoparticles supported on Titanium Nitride (TiN) using a facile wet chemical method without high-temperature pre-treatment. The well-dispersed Ir NPs firmly anchored on TiN support and systematically annealed at different temperatures to investigate their structural and catalytic performance for acidic OER. The Ir@TiN-500 catalyst, obtained after calcination at 500 °C, demonstrated superior OER performance, with a mass activity of 342 A/g_Ir at 1.54 V, and maintained its structure and stability. X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) analysis provides insights into the changes in Ir nanoparticles evolution from an EDTA-bound oxidized state to agglomerated metallic particles. The use of surfactant and thermal annealing fine-tuned the metal-support interactions, resulting in the optimized Ir@TiN-500 catalyst that maintained an optimal morphology with both Ir-O and Ir-Ir bonds in coexistence. This Ir-templated IrOx system achieves a good balance between atomic utilization efficiency and catalyst stability. These findings show controlled metal-support interaction in optimizing the structure and catalytic performance of iridium-based OER catalysts.
Poster #6: CO2 Hydrogenation over Rhodium Cluster Catalyst Nucleated within a Manganese Oxide Framework
Presenter: Shuting Xiang
Abstract: Rhodium-incorporated manganese oxide frameworks have been extensively studied for the catalytic conversion of carbon dioxide. These materials utilize three-dimensional MnOx structures as supportive matrices to stabilize and isolate Rh active centers. To enhance structural robustness and catalytic performance, various counterions, including V, Na, and Zn, were introduced for their known promotional effects. The choice of counterion and the structural properties of the host framework were found to significantly influence the catalytic activity. In our study, we employed cryptomelane-type tunnel manganese oxides, known as octahedral molecular sieves (OMS-2), as the support structure. Among the tested systems, Rh-V-OMS2 exhibited exceptional stability and sustained catalytic performance. Even after 48 hours on stream, the catalyst maintained a high and consistent CO2 conversion rate of approximately 1.5 × 10⁻4 mol CO2/gRh/s, outperforming other initially more active Rh-MnOx combinations. In situ X-ray absorption fine structure (XAFS) analysis revealed that Rh initially exists as atomically dispersed species, which nucleate into nanoparticles or sub-nanometer clusters during the reaction, with a coordination number of 5.5 or lower. A clear correlation was observed between particle size and reaction rate, suggesting that the catalytic performance could be finely tuned by controlling the size of Rh clusters. Furthermore, control experiments confirmed that the high activity originates from the unique metal–support interactions in the Rh-X-MnOx system.
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