SEARCH · Search NASA

Results for “catalyst stability”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 541 records · Page 30

All sources NASA NTRS DOE OSTI

DOE OSTI2023

Chemical and Structural Evolution of AgCu Catalysts in Electrochemical CO 2 Reduction

Silver–copper (AgCu) bimetallic catalysts hold great potential for electrochemical carbon dioxide reduction reaction (CO 2 RR), which is a promising way to realize the goal of carbon neutrality. Although a wide variety of AgCu catalysts have been developed so far, it is relatively less explored how these AgCu catalysts evolve during CO 2 RR. The absence of insights into their stability makes the dynamic catalytic sites elusive and hampers the design of AgCu catalysts in a rational manner. Here, in this study, we synthesized intermixed and phase-separated AgCu nanoparticles on carbon paper electrodes and investigated their evolution behavior in CO 2 RR. Our time-sequential electron microscopy and elemental mapping studies show that Cu possesses high mobility in AgCu under CO 2 RR conditions, which can leach out from the catalysts by migrating to the bimetallic catalyst surface, detaching from the catalysts, and agglomerating as new particles. Besides, Ag and Cu manifest a trend to phase-separate into Cu-rich and Ag-rich grains, regardless of the starting catalyst structure. The composition of the Cu-rich and Ag-rich grains diverges during the reaction and eventually approaches thermodynamic values, i.e., Ag 0.88 Cu 0.12 and Ag 0.05 Cu 0.95 . The separation between Ag and Cu has been observed in the bulk and on the surface of the catalysts, highlighting the importance of AgCu phase boundaries for CO 2 RR. In addition, an operando high-energy-resolution X-ray absorption spectroscopy study confirms the metallic state of Cu in AgCu as the catalytically active sites during CO 2 RR. Taken together, this work provides a comprehensive understanding of the chemical and structural evolution behavior of AgCu catalysts in CO 2 RR.

Chen, Peng-Cheng↗

DOE OSTI2020

The production of hydrogen–deuterium exchanged cellulose fibers with exchange-resistant deuterium incorporation

Production of deuterated cellulose is important from both theoretical and practical perspectives. Here, cellulose fibers of cotton and Tencel fibers with exchange-resistant deuterium incorporation were prepared by hydrogen–deuterium exchange treatment. The effect of the micro-structure of cellulose crystallinity index as well as the reaction conditions including catalyst, reaction time, and temperature on the exchange-resistant deuterium incorporation process are reported. The ability of deuterated cellulose fibers to resist protium-exchange during H 2 O washing was also explored. The results found that higher crystallinity index is beneficial to stabilize the deuteration of cellulose fibers. Furthermore, alkaline catalysts such as sodium hydroxide or potassium carbonate and higher exchange temperature as well as longer reaction time contribute significantly to the stabilization of deuterium incorporation in the deuterated cellulose fibers. These observations revealed that the hydrogen–deuterium exchange treatment is effective to obtain exchange-resistant deuterium incorporated cellulose fibers. In addition, cotton fibers with several deuteration levels were produced and could be considered for the study of deuterium effect on cellulose properties.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2020

Use of in Situ Synchrotron Techniques to Probe the Oxidized Surface of Molybdenum Nitride Oxygen Reduction Electrocatalysis

The development of active and stable earth-abundant catalysts for the oxygen reduction reaction (ORR) is needed for widespread, economic development of fuel cell technologies. Designing and optimizing these non-platinum group metals is challenging, however, because they are susceptible to composition and structure changes, including dissolution, oxidation, and corrosion, both in air and under reaction conditions. To identify the active surface, and thus understand the properties that affect activity, the catalyst surface must be characterized in situ. Herein, we utilize a grazing incidence electrochemical cell to investigate in situ composition and morphology changes of a molybdenum nitride (Mo-N) thin film catalyst using grazing incidence x-ray absorption spectroscopy (GI-XAS) and x-ray reflectivity (XRR). In rotating ring disk electrode measurements, we find that the activity, selectivity, stability, and capacitance of the Mo-N catalyst is dependent on the maximum potential to which it has been exposed. Specifically, the overpotential required to reach -2 mA cm-2geo decreases by over 90 mV when the maximum potential is increased from 0.3 to 0.8 V vs RHE (Figure 1). Because the Mo-N oxidizes rapidly in air, ex situ characterization methods including x-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry can provide only limited insight into these in situ catalyst changes. Using in situ GI-XAS measurements at applied potentials between 0.3 and 0.9 V vs RHE, however, we are able to determine that the surface of the film oxidizes and becomes more amorphous when exposed to increasingly higher potentials (Figure 1). Furthermore, the surface remains oxidized on the order of several hours when returned to "ORR relevant potentials" (< 0.6 V vs RHE), indicating that this surface-oxidized nitride is the active surface for ORR. Using in situ XRR measurements, we find that there is no change in surface roughness at potentials below 0.7 V vs RHE, but the film roughens significantly at 0.8 V vs RHE, correlating with ex situ measurements of Mo dissolution at this potential (Figure 1). We therefore conclude that the intrinsic activity of the Mo-N catalyst increases when exposed to potentials up to 0.7 V vs RHE, while above that potential activity enhancements are due to the exposure of more active sites through dissolution. The in situ electrochemical surface-sensitive x-ray characterization as used here is a promising methodology for understanding and leveraging surface dynamics to improve the performance of non-traditional catalysts.

Kreider, Melissa↗

DOE OSTI2025

Hybrid HEFA-HDCJ Process for the Production of Jet Fuel Blendstocks

The hydrotreatment of bio-oil derived from the pyrolysis and biocrude from hydrothermal liquefaction of lignocellulosic materials to produce hydrocarbons faces significant technological challenges, mainly due to the high reactivity and poor thermal stability of bio-oil, resulting in the formation of large quantities of coke. This problem has been addressed by existing PNNL patents with a two-step hydrotreatment technology in which the bio-oil is first stabilized with a noble hydrogenation metal (often Pt or Ru). Then, in the second step, the bio-oil is deoxygenated with a Ni-Mo or Co-Mo sulfide catalyst. The main problem with this approach is that the Pt/Ru catalysts deactivate easily in the presence of S or other impurities, which are commonly present in pyrolysis oils. In this project, we explored technological solutions to mitigate coke formation, avoiding the use of Pt/Ru catalysts. Our strategy is based on three actions: (1) Bio-oil stabilization in the presence of alcohols. In this project, we studied the stabilization with butanol. (2) the use of a cosolvent to solubilize the bio-oil. Because coke formation reactions are second-order reactions a reduction in the concentration of reactive bio-oil molecules. In this case, we used yellow greases as a co-solvent. (3) Separation of bio-oil reactive fractions. In this project, we studied the removal of water-soluble fractions. Our batch co-hydrotreatment studies confirmed that the addition of butanol and methanol and the blend with lipids effectively contributed to mitigating coke formation (reducing coke yield to about 1 wt.% %). The removal of sugars did not have a noticeable effect on the overall coke yield, suggesting that coke precursors are present in all bio-oil fractions. Our analytical work suggests that they may be concentrated in the water-insoluble/CH 2 Cl 2 insoluble fractions of pyrolysis oils. Although the technological strategies tested resulted in significant coke reductions, the levels achieved were not sufficiently low to ensure a reliable operation in continuous, fixed-bed trickle-bed reactors. Long runs of more than 100 hours (maximum: 255 h) of co-processing time on stream were achieved in a continuous 40 mL reactor. When the same test was conducted in a larger 400 mL reactor, pressure drop increases associated with coke formation were observed. This increase in coke formation could be due to larger temperature gradients in the bed. Hydrodeoxygenation tests in moving bed reactors and using more active hydrogenation catalysts (for example Ni) could lead to more reliable operations. Unfortunately, our team did not have access to such experimental setups. The technoeconomic analysis suggests that although alcohol use is an effective means to reduce coke formation, the use of alcohol increases production cost. Thus, its use needs to be minimized. A delicate balance needs to be found between the use of technological solutions that allow the reliable operation of the system (stabilization with Ni catalysts, use of small quantities of solvents, processing in moving bed reactors) with a tolerable level of coke formation for the hydrodeoxygenation reactor used and that result in minimum production costs.

09 BIOMASS FUELS↗

DOE OSTI2020

Silver Adsorption on Calcium Niobate(001) Nanosheets: Calorimetric Energies That Explain Sinter-Resistant Support

Metal nanoparticles deposited on oxide supports are essential to many technologies, including catalysts, fuel cells and electronics. Therefore, understanding the chemical bonding strength between metal nanoparticles and oxide surfaces is of great interest. The adsorption energetics, adhesion energy and adsorbate structure of Ag on dehydrated HCa 2 Nb 3 O 10 (001) nanosheets at 300 K have been studied using metal adsorption calorimetry and surface spectroscopies. These dehydrated (“dh”) calcium niobate nanosheets “(dh-HCa 2 Nb 3 O 10 (001))” have stoichiometry Ca 4 Nb 6 O 19 . They impart unusual stability to metal nanoparticles when used as catalyst supports and are easy-to-prepare by Langmuir-Blodgett (LB) techniques, highly ordered, and essentially single-crystal surfaces of mixed oxides with a huge ratio of terrace to edge sites. Below monolayer coverage, Ag grows on dh-HCa 2 Nb 3 O 10 (001) as 2D islands of thickness ~2 layers. The differential heat of Ag adsorption is initially ~303 kJ/mol, increasing slowly to ~338 kJ/mol by 0.8 ML. At higher coverages, Ag atoms mainly add on top of these 2D islands, growing 3D nanoparticles of increasing thickness, as the heat decreases asymptotically towards silver’s heat of sublimation (285 kJ/mol). The adhesion energy of Ag(s) to this Ca niobate surface is estimated to be 4.33 J/m 2 , larger than on any oxide surface previously measured. This explains the sinter resistance reported for metal nanoparticles on this support. Electron transfer from Ag into the calcium niobate is also measured. Furthermore, these results demonstrate an easy way to do singlecrystal-type surface science studies - and especially thermochemical measurements - on the complex surfaces of mixed oxides: using LB-deposited perovskite nanosheets and ultrahigh vacuum annealing in O 2 .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2024

Role of H 2 O in Catalytic Conversion of C 1 Molecules

Due to their role in controlling global climate change, the selective conversion of C 1 molecules such as CH 4 , CO, and CO 2 has attracted widespread attention. Typically, H 2 O competes with the reactant molecules to adsorb on the active sites and therefore inhibits the reaction or causes catalyst deactivation. However, H 2 O can also participate in the catalytic conversion of C 1 molecules as a reactant or a promoter. Herein, we provide a perspective on recent progress in the mechanistic studies of H 2 O-mediated conversion of C 1 molecules. We aim to provide an in-depth and systematic understanding of H 2 O as a promoter, a proton-transfer agent, an oxidant, a direct source of hydrogen or oxygen, and its influence on the catalytic activity, selectivity, and stability. We also summarize strategies for modifying catalysts or catalytic microenvironments by chemical or physical means to optimize the positive effects and minimize the negative effects of H 2 O on the reactions of C 1 molecules. Finally, we discuss challenges and opportunities in catalyst design, characterization techniques, and theoretical modeling of the H 2 O-mediated catalytic conversion of C 1 molecules.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

Evaluating the stability and activity of dilute Cu-based alloys for electrochemical CO 2 reduction

Cu-based catalysts currently offer the most promising route to actively and selectively produce value-added chemicals via electrochemical reduction of CO 2 (eCO 2 R); yet further improvements are required for their wide-scale deployment in carbon mitigation efforts. Here, we systematically investigate a family of dilute Cu-based alloys to explore their viability as active and selective catalysts for eCO 2 R through a combined theoretical–experimental approach. Using a quantum–classical modeling approach that accounts for dynamic solvation effects, we assess the stability and activity of model single-atom catalysts under eCO 2 R conditions. Our calculations identify that the presence of eCO2R intermediates, such as CO*, H*, and OH*, may dynamically influence the local catalyst surface composition. Additionally, we identify through binding energy descriptors of the CO*, CHO*, and OCCO* dimer intermediates that certain elements, such as group 13 elements (B, Al, and Ga), enhance the selectivity of C 2+ species relative to pure Cu by facilitating CO dimerization. The theoretical work is corroborated by preliminary testing of eCO 2 R activity and selectivity of candidate dilute Cu-based alloy catalyst films prepared by electron beam evaporation in a zero-gap gas diffusion electrode-based reactor. Of all studied alloys, dilute CuAl was found to be the most active and selective toward C 2+ products like ethylene, consistent with the theoretical predictions. Finally, we attribute the improved performance of dilute CuAl alloys to more favorable dimerization reaction energetics of bound CO species relative to that on pure Cu. In a broader context, the results presented here demonstrate the power of our simulation framework in terms of rational catalyst design.

30 DIRECT ENERGY CONVERSION↗

DOE OSTI2020

Recent progress in the durability of Fe-N-C oxygen reduction electrocatalysts for polymer electrolyte fuel cells

This mini-review article review focuses on the very recent advancements in the stability and durability under operating fuel cell conditions of Fe-N-C electrocatalysts oxygen reduction reaction (ORR) catalysts. The most prominent degradation mechanisms of active site demetallation and carbon corrosion, both resulting in a relatively rapid initial performance loss, are introduced and elaborated on through recent published work, with emphasis on the role of H 2 O 2 radicals in these two likely catalysts degradation mechanisms. Here, the current state of Fe-N-C electrocatalysts is also discussed and several specific improvements are proposed as necessary to advance these materials towards a state of competitive stability and durability.

25 ENERGY STORAGE↗

DOE OSTI2020

Rhombohedral Ordered Intermetallic Nanocatalyst Boosts the Oxygen Reduction Reaction

Low platinum-group-metal (PGM) ordered intermetallic catalysts have been considered one of the most promising candidates for catalyzing the oxygen reduction reaction (ORR) in fuel cells, but achieving the desired performances in terms of activity, durability, and cost is still a grand challenge for the fuel cell research field. While the cubic- and tetragonal-ordered (L1 2 and L1 0 phases) low-PGM nanocatalysts have been investigated extensively and have shown considerably improved durability and activity toward the ORR, so far, little is known about rhombohedral ordered L1 1 catalysts. Here, we report the synthesis of an L1 1 -ordered PtCu catalyst for the ORR. We demonstrate that by applying nitrogen (N) doping through a thermal treatment in an NH 3 gas, the activity and stability of the N-doped, rhombohedral ordered PtCu catalyst can be further enhanced, and the ORR mass and specific activities achieve nearly 5-fold and 4-fold enhancement in acidic media, respectively, relative to those of commercial Pt/C. In situ synchrotron X-ray absorption and pair-distribution-function measurements reveal that both the formation of the ordered intermetallic structure and N-doping synergistically improve the corrosion resistance of the PtCu catalyst by lowering the Cu diffusivity and introduce a compressive strain effect regulating the adsorption of oxygenated species on the Pt surface, thus accounting for the improved ORR kinetics.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2024

Platinum on High-Entropy Aluminate Spinels as Thermally Stable CO Oxidation Catalysts

Thermal degradation is a leading cause of automotive catalyst deactivation. Because high-entropy oxides are uniquely stabilized at high temperatures via an increase in configurational entropy, these materials may offer new mechanisms for preventing the thermal deactivation of precious metal catalysts. In this work, we evaluated platinum loaded on simple and high-entropy aluminate spinels (MAl 2 O 4 , where M = Co, Cu, Mg, Ni, or mixtures thereof) in carbon monoxide oxidation before and after aging at 800 °C. Pt supported on all simple spinels showed significant deactivation after thermal aging compared to the fresh samples, with T 90 increasing by at least 60 °C. However, Pt on high-entropy spinels had nearly the same or better activity after aging, with T 90 increasing by only 6 °C at most. During aging and reduction, copper exsolved from the spinel supports and alloyed with platinum. This interaction promoted low temperature oxidation activity, presumably through weakened CO binding, but did not prevent deactivation. On the other hand, Co, Mg, and Ni constituents promoted stronger CO bonding, as evidenced by apparent negative order kinetics and poor activity at low temperatures. High-entropy spinels, containing a variety of active metals, displayed synergetic reactant adsorption capacity and cooperative effects with supported platinum particles, which collectively prevented thermal deactivation.

CO oxidation↗

DOE OSTI2024

Covalent Functionalization of Silicon with Plasma-Grown “Fuzzy” Graphene: Robust Aqueous Photoelectrodes for CO 2 Reduction by Molecular Catalysts

Carbon electrodes are ideal for electrochemistry with molecular catalysts, exhibiting facile charge transfer and good stability. Yet for solar-driven catalysis with semiconductor light absorbers, stable semiconductor/carbon interfaces can be difficult to achieve, and carbon’s high optical extinction means it can only be used in ultrathin layers. Here, we demonstrate a plasma-enhanced chemical vapor deposition process that achieves well-controlled deposition of out-of-plane “fuzzy” graphene (FG) on thermally oxidized Si substrates. The resulting Si|FG interfaces possess a silicon oxycarbide (SiOC) interfacial layer, implying covalent bonding between Si and the FG film that is consistent with the mechanical robustness observed from the films. The FG layer is uniform and tunable in thickness and optical transparency by deposition time. Using p-type Si|FG substrates, noncovalent immobilization of cobalt phthalocyanine (CoPc) molecular catalysts was employed for the photoelectrochemical reduction of CO 2 in aqueous solution. The Si|FG|CoPc photocathodes exhibited good catalytic activity, yielding a current density of ∼1 mA/cm 2 , Faradaic efficiency for CO of ∼70% (balance H 2 ), and stable photocurrent for at least 30 h at −1.5 V vs Ag/AgCl under 1-sun illumination. Furthermore, the results suggest that plasma-deposited FG is a robust carbon electrode for molecular catalysts and suitable for further development of aqueous-stable Si photocathodes for CO 2 reduction.

CO2 reduction↗

DOE OSTI2020

Electronic Structure of Atomically Dispersed Supported Iridium Catalyst Controls Iridium Aggregation

Supported iridium complexes, Ir(C 2 H 4 ) 2 /support, were characterized by X-ray absorption spectroscopy during a temperature ramp to 120 °C in flowing H 2 . Iridium in complexes bonded to weak and moderate electron-donor supports, SiO 2 and γ-Al 2 O 3 , underwent aggregation, forming nanoparticles and clusters, respectively. When the support was a strong electron-donor (MgO), iridium remained site-isolated. Density functional theory calculations confirm the dependence of iridium–support bond strength on the support’s electron-donor character. Coating the SiO 2 -supported complexes with 1-n-ethyl-3-methyl-imidazolium acetate enhanced electron density on the iridium, hindering its aggregation. Finally, these results demonstrate opportunities for stabilizing atomically dispersed supported noble metals under reducing conditions by choice of support/ionic liquid sheath combinations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2022

TiO x -supported Na-Mn-W oxides for the oxidative coupling of methane

Supported Na-Mn-W oxides are among the most studied catalysts for the oxidative coupling of methane (OCM) because of their superior thermal stability and relatively high C 2+ product yields. However, because of the structural complexity, the roles of each component in these catalysts have been controversial. In this work, WO x and MnO x sites were supported on titanate nanowires and employed in OCM studies. Compared to the commonly studied silica support, which is subject to severe restructuring due to the Na-induced crystallization, titanate support not only serves as a reservoir for alkali metals (e.g., Na), but also stabilizes isolated MnO x species. The catalytic performance of the titanate-based catalyst is similar to that of reference catalyst, MnO x /Na 2 WO 4 /SiO 2 , with a synergistic effect between MnO x and WO x sites. Further, advanced electron microscopy, X-ray diffraction, infrared spectroscopy, and X-ray absorption near edge structure spectroscopy suggest that the basic NaO x and MnO x species have strong interactions with the acidic WO x and TiO x species, which might contribute to the high selectivity toward C 2+ products and suppressed CO x formation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2022

Ordered CoPt oxygen reduction catalyst with high performance and durability

A high-performance and durable polymer electrolyte membrane fuel cell cathode catalyst composed of an ordered L10–CoPt core and a thin Pt shell was designed and prepared. Under practical fuel cell membrane electrode assembly testing conditions, the cathode catalyst showed an outstanding initial mass activity of 0.6 A/mgPt, which satisfies the U.S. Department of Energy performance target while also meeting the durability target of less than 40% loss in mass activity after 30,000 accelerated stress test voltage cycles. The high structural stability of the L10–CoPt@Pt-shell catalyst was confirmed by postmortem materials characterization, and the origin of this robustness was revealed by density functional theory calculations, where the barriers for diffusion of Co atoms were observed to be significantly increased in the ordered intermetallic core.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Regioselective Generation of Single‐Site Iridium Atoms and Their Evolution into Stabilized Subnanometric Iridium Clusters in MWW Zeolite

Abstract Preparation of supported metal catalysts with uniform particle size and coordination environment is a challenging and important topic in materials chemistry and catalysis. In this work, we report the regioselective generation of single‐site Ir atoms and their evolution into stabilized subnanometric Ir clusters in MWW zeolite, which are located at the 10MR window connecting the two neighboring 12MR supercages. The size of the subnanometric Ir clusters can be controlled by the post‐synthesis treatments and maintain below 1 nm even after being reduced at 650 °C, which cannot be readily achieved with samples prepared by conventional impregnation methods. The high structure sensitivity, size‐dependence, of catalytic performance in the alkane hydrogenolysis reaction of Ir clusters in the subnanometric regime is evidenced.

Liu, Lichen↗

DOE OSTI2020

Regioselective Generation of Single‐Site Iridium Atoms and Their Evolution into Stabilized Subnanometric Iridium Clusters in MWW Zeolite

Liu, Lichen↗

DOE OSTI2024

Constructing Highly Porous Low Iridium Anode Catalysts Via Dealloying for Proton Exchange Membrane Water Electrolyzers

Iridium (Ir) is the most active and durable anode catalyst for the oxygen evolution reaction (OER) for proton exchange membrane water electrolyzers (PEMWEs). However, their large-scale applications are hindered by high costs and scarcity of Ir. Lowering Ir loadings below 1.0 mgcm -2 causes significantly reduced PEMWE performance and durability. Therefore, developing efficient low Ir-based catalysts is critical to widely commercializing PEMWEs. Herein, an approach is presented for designing porous Ir metal aerogel (MA) catalysts via chemically dealloying IrCu alloys. In this study, the unique hierarchical pore structures and multiple channels of the Ir MA catalyst significantly increase electrochemical surface area (ECSA) and enhance OER activity compared to conventional Ir black catalysts, providing an effective solution to design low-Ir catalysts with improved Ir utilization and enhanced stability. An optimized membrane electrode assembly (MEA) with an Ir loading of 0.5 mg Ir cm -2 generated 2.0 A cm -2 at 1.79 V, higher than the Ir black at a loading of 2.0 mg Ir cm -2 (1.63 A cm -2 ). The low-Ir MEA demonstrated an acceptable decay rate of ≈40 µV h -1 during durability tests at 0.5 (>1200 h) and 2.0 A cm -2 (400 h), outperforming the commercial Ir-based MEA (175 µV h -1 at 2.0 mg Ir cm -2 ).

36 MATERIALS SCIENCE↗

DOE OSTI2026

Sparsely Dispersed CeO x ‑Stabilized Pt Nanoparticles Overcome Pt Loading–Durability Trade-Off for Highly Durable Heavy-Duty Fuel Cells

Proton-exchange-membrane fuel cells (PEMFCs) are clean and sustainable mobile power sources for transportation. Recently, their deployment in heavy-duty vehicles (HDVs) has attracted growing interest owing to their high energy scalability and lower infrastructure requirements. However, to meet the stringent requirements for efficiency and long-term durability for HDV applications, PEMFCs typically employ a relatively high platinum group metal (PGM) loading (>0.2 mg PGM /cm 2 ). This elevated PGM loading significantly increases the stack and system costs, surpassing the U.S. Department of Energy (DOE) target of $\$ 60$/kW for commercial viability. Reducing PGM loading while maintaining performance and durability remains a central challenge for HDV fuel cells. Here we exploit metal oxide–Pt interactions and utilize the strong CeO x –Pt interaction to design a CeO x @Pt catalyst structure with exceptional durability. At a low total PGM loading (0.1 mg PGM /cm 2 ), the CeO x @Pt/C catalyst demonstrates high fuel cell performance (8.8 kW/g PGM ) and stability (power retention >90%) after the challenging HDV durability testing (90,000 accelerated-stress-test cycles). With the CeO x @Pt/C catalyst, we showcase over 70% reduction in Pt cost from the M2FCT target (to $\$ 9$/kW), highlighting its promising potential for enabling stable and cost-effective fuel cell systems for heavy-duty applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗