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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.

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At least 1,207 records · Page 67
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Two-Dimensional Binary Superlattice of BNNT-Surfactant Vesicle Complex Induced by Electrostatic Interaction

For a wide range of practical applications of boron nitride nanotubes (BNNTs), it is essential to achieve their highly ordered self-assembled structures. This study reports on a two-dimensional (2D) binary superlattice of individually exfoliated BNNTs with a negative surface charge (p-BNNT25) and cationic surfactant vesicles (CTAT/SDBS vesicles, prepared by mixing cetyltrimethylammonium tosylate (CTAT) and sodium dodecylbenzenesulfonate (SDBS)) complexes through electrostatic interactions. Depending on the surface charge density of the CTAT/SDBS vesicles and the mass ratio between the CTAT/SDBS vesicle and p-BNNT25, the CTAT/SDBS-BNNT complexes formed highly ordered superstructures. These structures include an intercalated lamellar phase with a centered rectangular structure (ICLP), in which a 2D array of p-BNNT25 is inserted into the multilamellar structure, and an AB 3 structure, in which the BNNTs are surrounded by surfactant micelles in a triangular arrangement. To the best of our knowledge, this is the first demonstration of the fabrication of highly ordered superstructures of individually exfoliated and negatively charged BNNTs with positively charged surfactant vesicles through electrostatic interactions. This approach for the 2D binary superlattices of CTAT/SDBS-BNNT complexes induced by electrostatic interactions is expected to be beneficial for a wide range of one-dimensional (1D) nanoparticle applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Nonadiabatic Dynamics in a Continuous Circularly Polarized Laser Field with Floquet Phase-Space Surface Hopping

Non-adiabatic chemical reactions involving continuous circularly polarized light (cw CPL) have not attracted as much attention as dynamics in unpolarized/linearly polarized light. However, including circularly (in contrast to linearly) polarized light allows one to effectively introduce a complex-valued time-dependent Hamiltonian, which offers a new path for control or exploration through the introduction of Berry forces. Here, we investigate several inexpensive semiclassical approaches for modeling such nonadiabatic dynamics in the presence of a time-dependent complex-valued Hamiltonian, beginning with a straightforward instantaneous adiabatic fewest-switches surface hopping (IA-FSSH) approach (where the electronic states depend on position and time), continuing to a standard Floquet fewest switches surface hopping (F-FSSH) approach (where the electronic states depend on position and frequency), and ending with an exotic Floquet phase-space surface hopping (F-PSSH) approach (wherethe electronic states depend on position, frequency, and momentum). Using a set of model systems with time-dependent complex-valued Hamiltonians, we show that the Floquet phase- space adiabats are the optimal choice of basis as far as accounting for Berry phase effects and delivering accuracy. Furthermore, the F-PSSH algorithm sets the stage for modeling nonadiabatic dynamics under strong externally pumped circular polarization in the future.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Covalent Attachment of the Water‐insoluble Ni(P Cy 2 N Phe 2 ) 2 Electrocatalyst to Electrodes Showing Reversible Catalysis in Aqueous Solution

Abstract Hydrogenases are a diverse group of metalloenzymes which catalyze the reversible conversion between molecular hydrogen and protons at high rates. The catalytic activity of these enzymes does not require overpotential because their active site has been evolutionarily optimized to operate fast and efficiently. These enzymes have inspired the development of molecular catalysts, which have dramatically improved in efficiency in recent years, to the point that some synthetic catalysts even outperform hydrogenases under certain conditions. In this work, we use a reversible noble‐metal‐free homogeneous catalyst, the [Ni(P Cy 2 N Phe 2 ) 2 ] 2+ complex, and we covalently immobilize it on a functionalized highly oriented pyrolytic graphite “edge” (HOPG e ) electrode surface. This catalyst is not water soluble, but once it is surface‐confined on the electrode, it maintains its catalytic properties in aqueous solutions, showing reversibility for H 2 oxidation/reduction. Immobilization of the [Ni(P Cy 2 N Phe 2 ) 2 ] 2+ complex onto a multi‐walled carbon nanotubes coated electrode leads to even higher catalytic current densities and enhanced stability.

Rodríguez‐Maciá, Patricia↗
DOE OSTI2024

Charge‐Programmable Photopolymers for 3D Electronics via Additive Manufacturing

Charge‐programmed 3D printing enables the fabrication of 3D electronics with lightweight and high precision via selective patterning of metals. This selective metal deposition is catalyzed by Pd nanoparticles that are specifically immobilized onto the charged surface and promises to fabricate a myriad of complex electronic devices with self‐sensing, actuation, and structural elements assembled in a designed 3D layout. However, the achievable property space and the material‐performance correlation of the charge‐programmed printing remain unexplored. Herein, a series of photo‐curable resins are designed for unveiling how the charge and crosslink densities synergistically impact the nanocatalyst‐guided selective deposition in catalytic efficiency and properties of the 3D printed charge‐programmed architectures, leading to high‐quality 3D patterning of solid and liquid metals. The findings offer a wide tunability of the structural properties of the printed electronics, ranging from stiff to extreme flexibility. Capitalizing on these results, the printing and successful application of an ultralight‐weight and deployable 3D multi‐layer antenna system operating at an ultrahigh‐frequency of 19 GHz are demonstrated.

36 MATERIALS SCIENCE↗
DOE OSTI2021

New Mechanistic and Reaction Pathway Insights for Oxidative Coupling of Methane (OCM) over Supported Na 2 WO 4 /SiO 2 Catalysts

Abstract The complex structure of the catalytic active phase, and surface‐gas reaction networks have hindered understanding of the oxidative coupling of methane (OCM) reaction mechanism by supported Na 2 WO 4 /SiO 2 catalysts. The present study demonstrates, with the aid of in situ Raman spectroscopy and chemical probe (H 2 ‐TPR, TAP and steady‐state kinetics) experiments, that the long speculated crystalline Na 2 WO 4 active phase is unstable and melts under OCM reaction conditions, partially transforming to thermally stable surface Na‐WO x sites. Kinetic analysis via temporal analysis of products (TAP) and steady‐state OCM reaction studies demonstrate that ( i ) surface Na‐WO x sites are responsible for selectively activating CH 4 to C 2 H x and over‐oxidizing CH y to CO and ( ii ) molten Na 2 WO 4 phase is mainly responsible for over‐oxidation of CH 4 to CO 2 and also assists in oxidative dehydrogenation of C 2 H 6 to C 2 H 4 . These new insights reveal the nature of catalytic active sites and resolve the OCM reaction mechanism over supported Na 2 WO 4 /SiO 2 catalysts.

Sourav, Sagar↗
DOE OSTI2021

New Mechanistic and Reaction Pathway Insights for Oxidative Coupling of Methane (OCM) over Supported Na 2 WO 4 /SiO 2 Catalysts

Abstract The complex structure of the catalytic active phase, and surface‐gas reaction networks have hindered understanding of the oxidative coupling of methane (OCM) reaction mechanism by supported Na 2 WO 4 /SiO 2 catalysts. The present study demonstrates, with the aid of in situ Raman spectroscopy and chemical probe (H 2 ‐TPR, TAP and steady‐state kinetics) experiments, that the long speculated crystalline Na 2 WO 4 active phase is unstable and melts under OCM reaction conditions, partially transforming to thermally stable surface Na‐WO x sites. Kinetic analysis via temporal analysis of products (TAP) and steady‐state OCM reaction studies demonstrate that ( i ) surface Na‐WO x sites are responsible for selectively activating CH 4 to C 2 H x and over‐oxidizing CH y to CO and ( ii ) molten Na 2 WO 4 phase is mainly responsible for over‐oxidation of CH 4 to CO 2 and also assists in oxidative dehydrogenation of C 2 H 6 to C 2 H 4 . These new insights reveal the nature of catalytic active sites and resolve the OCM reaction mechanism over supported Na 2 WO 4 /SiO 2 catalysts.

Sourav, Sagar↗
DOE OSTI2016

K-decompositions and 3d gauge theories

This paper combines several new constructions in mathematics and physics. Mathematically, we study framed flat PGL(K, C)-connections on a large class of 3-manifolds M with boundary. We introduce a moduli space $\mathcal{L}$ K (M) of framed flat connections on the boundary ∂M that extend to M. Our goal is to understand an open part of $\mathcal{L}$ K (M) as a Lagrangian subvariety in the symplectic moduli space X un K (∂M) of framed flat connections on the boundary — and more so, as a “K 2 -Lagrangian,” meaning that the K 2 -avatar of the symplectic form restricts to zero. We construct an open part of $\mathcal{L}$ K (M) from elementary data associated with the hypersimplicial K-decomposition of an ideal triangulation of M, in a way that generalizes (and combines) both Thurston’s gluing equations in 3d hyperbolic geometry and the cluster coordinates for framed flat PGL(K, C)-connections on surfaces. By using a canonical map from the complex of configurations of decorated flags to the Bloch complex, we prove that any generic component of $\mathcal{L}$ K (M) is K 2 -isotropic as long as ∂M satisfies certain topological constraints (theorem 4.2). In some cases this easily implies that $\mathcal{L}$ K (M) is K 2 -Lagrangian. For general M, we extend a classic result of Neumann and Zagier on symplectic properties of PGL(2) gluing equations to reduce the K 2 -Lagrangian property to a combinatorial statement. Physically, we translate the K-decomposition of an ideal triangulation of M and its symplectic properties to produce an explicit construction of 3d N = 2 superconformal field theories T K [M] resulting (conjecturally) from the compactification of K M5-branes on M. This extends known constructions for K = 2. Just as for K = 2, the theories T K [M] are described as IR fixed points of abelian Chern-Simons-matter theories. Changes of triangulation (2-3 moves) lead to abelian mirror symmetries that are all generated by the elementary duality between N f = 1 SQED and the XYZ model. In the large K limit, we find evidence that the degrees of freedom of T K [M] grow cubically in K.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Quantifying root water extraction after drought recovery using sub-mm in situ empirical data

Root-specific responses to stress are not well-known, and have been largely based on indirect measurements of bulk soil water extraction, which limits mechanistic modeling of root function. Here, we used neutron radiography to examine in situ root-soil water dynamics of a previously droughted black cottonwood ( Populus trichocarpa ) seedling, contrasting water uptake by younger, thinner or older, thicker parts of the fine root system. The smaller diameter roots had greater water uptake capacity per unit surface area than the larger diameter roots, but they had less total surface area leading to less total water extraction; rates ranged from 0.0027 – 0.0116 g cm -2 hr -1 . The finest most-active roots were not visible in the radiographs, indicating the need to include destructive sampling. Analysis based on bulk soil hydraulic properties indicated substantial redistribution of water via saturated/unsaturated flow, capillary wicking, and root hydraulic redistribution across the layers - suggesting water uptake dynamics following an infiltration event may be more complex than approximated by common soil hydraulic or root surface area modeling approaches. Lastly, our results highlight the need for continued exploration of root-trait specific water uptake rates in situ, and impacts of roots on soil hydraulic properties – both critical components for mechanistic modeling of root function.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Evolution of global and local deformation in additively manufactured octet truss lattice structures

Additively manufactured lattice truss structures, often referred to as architected cellular materials, present significant advantages over conventional structures due to their unique characteristics such as high strength-to-weight ratios and surface area-to-volume ratios. These geometrically complex structures, however, come with concomitant challenges for qualification and inspection. In this study, compression testing interrupted with micro-computed tomography inspection was conducted to monitor the evolution of global and local deformation throughout the loading process of 304L stainless steel octet truss lattice structures. Both two- and three-dimensional image analysis techniques were leveraged to characterize geometric heterogeneities resulting from the laser powder bed fusion manufacturing process as well as track the structure throughout deformation. Variations from model-predicted behavior resulting from these heterogeneities are considered relative to the predicted and actual responses of the structures during compression to better understand, model, and predict the octet truss lattice structure compression response.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Computational catalyst screening: Scaling, bond-order and catalysis

Here, the design of new and better heterogeneous catalysts needed to accommodate the growing demand for energy from renewable sources is an important challenge for coming generations. Most surface catalyzed processes involve a large number of complex reaction networks and the energetics ultimately defines the turn-over-frequency and the selectivity of the process. In order not to get lost in the large quantities of data, simplification schemes that still contain the key elements of the reaction are required. Adsorption and transition state scaling relations constitutes such a scheme that not only maps the reaction relevant information in terms of few parameters but also provides an efficient way of screening for new materials in a continuous multi-dimensional energy space. As with all relations they impose certain restrictions on what can be achieved and in this paper, I show why these limitations exist and how we can change the behavior through an energy-resolved approach that still maintains the screening capabilities needed in computational catalysis.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Aspartate transformation at 200 °C with brucite [Mg(OH) 2 ], NH 3 , and H 2 : Implications for prebiotic molecules in hydrothermal systems

Hydrothermal systems may have been favorable environments for the evolution of prebiotic chemistry on early Earth due to the presence of chemical, temperature, and redox gradients that could promote the formation of biomolecules. However, the relevance of these environments in origins of life scenarios has been debated due to rapid decomposition of biologically essential species, such as amino acids, at high temperatures. Little is known about the reactivity of amino acids in the presence of mineral surfaces and reducing conditions, which reflect the geochemical complexities of environments such as serpentinite-hosted hydrothermal vents. We investigated the decomposition of 25 mM aspartate at 200 °C and 15.5 bars (P SAT ) in gold capsules both with and without brucite [Mg(OH) 2 ], a mineral product of serpentinization, and reducing conditions (NH 4 Cl and H 2(aq) ). Here we observed that the reaction products of aspartate vary significantly with the initial reaction conditions. Fluids containing aspartate only decomposed to fumarate, maleate, malate, acetate, and trace amounts of succinate and glycine. However, under reducing conditions, the main product was succinate (8 mM) and also approximately 1 mM total of the amino acids glycine, α-alanine, and β-alanine. The amount of α-alanine increased three-fold with brucite. Furthermore, we detected a two-fold decrease in the fumarate concentration, whereas total maleate concentration dramatically decreased over ten-fold and resulted in an overall increase in the trans/cis ratio of these deamination products of aspartate from 0.9 to 4.5 as a function of brucite loading. This net decrease in fumarate and maleate concentration and the five-fold increase in the trans/cis ratio might have been caused by a combination of a pH increase and the formation of magnesite due to increased Mg 2 + ion concentration. The results of this study provide evidence that the fundamental properties of a hydrothermal system, including mineral assemblages, reducing conditions, and dissolved species concentrations, will influence the fate of amino acids at high temperature.

58 GEOSCIENCES↗
DOE OSTI2021

Influence of ethylenediaminetetraacetic acid on the long-term oxidation state distribution of plutonium

Here, spectrophotometry was used to study the effect of EDTA on plutonium oxidation state distribution as a function of time, pH, and ligand-to-metal ratio (L/M) under anoxic conditions. Novel Pu(V)-EDTA absorption bands were identified at 571, 993, 1105, and 1150 nm with molar absorption coefficients of 15 ± 1, 6 ± 1, 10 ± 1, and 10 ± 1 cm –1 M –1 , respectively. Pu(V)-EDTA spectral changes occurred at L/M < 1, indicating only Pu V O 2 (EDTA) 3- formed with logK = 3.6 ± 0.3. Time-resolved experiments showed EDTA drastically increased the Pu(V/VI) reduction rate, which we propose is driven by amine lone-pair electron donation and the oxidative decarboxylation of EDTA. Oxidation of Pu(III)-EDTA to Pu(IV)-EDTA occurred on a slower time scale (110–237 days) than previously reported (<15 min) and is hypothesized to be radiolysis driven. Pu(V/VI)-EDTA and Pu(III)-EDTA both approached Pu(IV)-EDTA stabilization over time, yet Pu(V/VI)-EDTA solubility data was ≥ 1.0 log 10 units higher than predicted by Pu(IV)-EDTA solubility models, indicating that current thermodynamic models are incomplete. Ultimately, the data show EDTA preferentially stabilizes Pu(IV) over time regardless of initial oxidation state, but Pu(V)-EDTA can persist under environmentally-relevant conditions, emphasizing the need to continue investigating redox reactions, speciation, and behavior of these complexes to support the transuranic waste disposal and surface remediation/containment efforts.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2016

Thermodynamic complexity of sulfated zirconia catalysts

Here, a series of sulfated zirconia (SZ) catalysts were synthesized by immersion of amorphous zirconium hydroxide in sulfuric acid of various concentrations (1–5 N). Additionally, these samples were fully characterized by X-ray diffraction (XRD), thermogravimetric analysis and mass spectrometry (TGA-MS), and aqueous sulfuric acid immersion and high temperature oxide melt solution calorimetry. We investigated the enthalpies of the complex interactions between sulfur species and the zirconia surface (ΔH SZ ) for the sulfated zirconia precursor (SZP), ranging from -109.46 ± 7.33 (1 N) to -42.50 ± 0.89 (4 N) kJ/mol S. ΔHSZ appears to be a roughly exponential function of sulfuric acid concentration. On the other hand, the enthalpy of SZ formation (ΔH f ), becomes more exothermic linearly as sulfur surface coverage increases, from -147.90 ± 4.16 (2.14 nm -2 ) to -317.03 ± 4.20 (2.29 nm -2 ) kJ/mol S, indicating formation of energetically more stable polysulfate species.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Radiocesium interaction with clay minerals: Theory and simulation advances Post–Fukushima

Insights at the microscopic level of the process of radiocesium adsorption and interaction with clay mineral particles have improved substantially over the past several years, triggered by pressing social issues such as management of huge amounts of waste soil accumulated after the Fukushima Dai-ichi nuclear power plant accident. In particular, computer-based molecular modeling supported by advanced hardware and algorithms has proven to be a powerful approach. Its application can now generally encompass the full complexity of clay particle adsorption sites from basal surfaces to interlayers with inserted water molecules, to edges including fresh and weathered frayed ones. On the other hand, its methodological schemes are now varied from traditional force-field molecular dynamics on large-scale realizations composed of many thousands of atoms including water molecules to first-principles methods on smaller models in rather exacting fashion. In this article, we overview new understanding enabled by simulations across methodological variations, focusing on recent insights that connect with experimental observations, namely: 1) the energy scale for cesium adsorption on the basal surface, 2) progress in understanding the structure of clay edges, which is difficult to probe experimentally, 3) cesium adsorption properties at hydrated interlayer sites, 4) the importance of the size relationship between the ionic radius of cesium and the interlayer distance at frayed edge sites, 5) the migration of cesium into deep interlayer sites, and 6) the effects of nuclear decay of radiocesium. Key experimental observations that motivate these simulation advances are also summarized. Furthermore, some directions toward future solutions of waste soil management are discussed based on the obtained microscopic insights.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Cations controlled growth of β-MnO 2 crystals with tunable facets for electrochemical energy storage

Engineering crystal facets to enhance their functionalities often require complex processing routes to suppress the growth of surfaces with the lowest thermodynamic energies. Herein, we report a unique method to control the morphologies of β-MnO 2 crystals with different occupancy of {100}/{111} facets through the effect of K + cations. Combining aberration-corrected scanning transmission electron microscopy (STEM), ultramicrotomy, and dynamic functional theory (DFT) simulation, we clarified that the β-MnO 2 crystals were formed through a direct solid-state phase transition process. Increasing the concentration of K + cations in the precursor gradually changed the morphology of β-MnO 2 from bipyramid prism ({100}+{111} facets) to an octahedron structure ({111} facets). The K + cations controlled the morphology of β-MnO 2 by affecting the formation of α-K 0.5 Mn 4 O 8 intermediate phase and the subsequent phase transition. Utilizing the β-MnO 2 crystals as the cathode for Li-ion batteries showed that highly exposed {111} facets offered β-MnO 2 crystal better rate performance, with ~70% capacity retention when the charge-discharge rate increased from 20 mA/g to 200 mA/g. Furthermore, our work revealed a new mechanism to tune the morphology of this earth-abundant metal oxide crystal, which could be used to adjust its electrochemical performance for different applications, such as supercapacitors and catalysts for metal-air batteries and fuel cells.

25 ENERGY STORAGE↗
DOE OSTI2019

Synthesis of Ni-Rich Thin-Film Cathode as Model System for Lithium Ion Batteries

We demonstrate a process to prepare model electrodes of the Ni-rich layered compound LiNi 0.6 Mn 0.2 Co 0.2 O 2 . These thin-film cathodes are compared with the composite materials to demonstrate the system is a viable platform for isolating interfacial phenomena between the electrolyte and active material without the influence of binders and conductive additives. The appropriate choice of heterolayers was found to influence the preferential orientation of the (101) and (104) planes relative to the (003) plane of the layered R-3m crystal structure, enhancing Li + diffusion and improving electrochemical performance. The addition of a Co interlayer between the Pt current collecting layer and alumina substrate increased the (101) and (104) texturing of the 500 nm Ni-rich film and allowed cells to deliver greater than 50% of their theoretical capacity. This work provides an architecture for isolating complex mechanisms of active materials that suffer from surface reconstruction and degradation in electrochemical cells.

25 ENERGY STORAGE↗
DOE OSTI2025

From Micro-environments to Macroscopic Effects: How the Alkaline Hydrogen Evolution Reaction Drives Cu Cathodic Corrosion

Cathodic corrosion of copper (Cu) has posed a significant challenge for over a century, impeding various technological progresses such as electrochemical conversion of CO 2 (eCO 2 RR) into fuels and other value-added carbon products. Here, in this study, employing a combined Density Functional Theory (DFT) and kinetic Monte Carlo (kMC) simulation approach, we delve into the atomistic level mechanism driving this phenomenon in Cu. Our hypothesis posits the pivotal role of alkaline hydrogen evolution reaction (HER) in facilitating cathodic corrosion in Cu. We rigorously develop a pH-dependent hydroxide (OH) adsorption mechanism and calculate the equilibrium OH coverage (𝜃 OH ) at varying pH levels, the thermodynamic stability of subsurface oxygen (O sub ), as well as the Cu-vacancy mediated diffusion of subsurface oxygens (O sub ). Through comprehensive analysis, we establish correlation among various microenvironments, including oxygen diffusion in subsurface layers, pH-dependent OH adsorption, and Cu dissolution into the electrolyte as (Cu-OH) complexes. Furthermore, our investigation explores the correlation between surface coordination environment of active sites and cathodic corrosion of Cu. Finally, by integrating DFT-derived thermodynamic data into a kMC model, we successfully predict the formation of experimentally observed corrosion pits on Cu-surfaces. This combined approach not only advances our fundamental understanding of Cu cathodic corrosion but also offers insights crucial for developing effective corrosion mitigation strategies.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Relationships between Atomic Level Surface Structure and Stability/Activity of Platinum Surface Atoms in Aqueous Environments

The development of alternative energy systems for clean production, storage and conversion of energy is strongly dependent on our ability to understand, at atomic-molecular-levels, functional links between activity and stability of electrochemical interfaces. Whereas structure-activity relationships are rapidly evolving, the corresponding structure-stability relationships are still missing. Primarily, this is because there is no adequate experimental approach capable of monitoring in situ stability of well-defined single crystals. Here, by blending the power of Inductively Coupled Plasma-Mass Spectrometer (ICP-MS) connected to a stationary probe to measure in situ and real time dissolution rates of surface atoms (at above 0.4 pg cm-2s-1 levels) and a rotating disk electrode method for monitoring simultaneously the kinetic rates of electrochemical reactions in a single unite, it was possible to establish almost “atom-by-atom” the structure-stability-activity relationships for platinum single crystals in both acidic and alkaline environments. Furthermore, we found that the degree of stability is strongly dependent on the coordination of surface atoms (less coordinated yields less stable), the nature of covalent (adsorption of hydroxyl, oxygen atoms and halides species), and non-covalent interactions (interactions between hydrated Li cations and surface oxide), the thermodynamic driving force for Pt complexation (Pt ion speciation in solution) and the nature of the electrochemical reaction (the oxygen reduction/evolution and CO oxidation reactions). Consequently, these findings are opening new opportunities for elucidating key fundamental descriptors that govern both activity and stability trends, that ultimately, will assist to develop real energy conversion and storage systems.

36 MATERIALS SCIENCE↗