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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 1,405 records · Page 78
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Refining whisker size of 2024Al/Al18B4O33w composite through extrusion and its effects on the material's micro-structures and mechanical properties

Highlights: • The nonuniform distributions of stress and velocity along whisker lead to whisker breakage. • The microcrack between broken whiskers can propagate into interface or matrix, related to the wedge angle of broken whisker. • The whisker breakage and staggered result in the decreasing distance between neighboring whiskers. • The smaller distance between neighboring whiskers reduces the resistance to the propagation of crack resulting in the lower ultimate tensile strength of extruded composite. - Abstract: Hot extrusion is used to improve the distribution of whiskers and refine the whisker sizes of 2024Al/Al{sub 18}B{sub 4}O{sub 33}w composite. The grain size and the ultimate tensile strength of the extruded 2024Al/Al{sub 18}B{sub 4}O{sub 33}w composite are analyzed. The results show that the average length of whiskers decreases due to the whisker breakage. The nonuniform distributions of stress and velocity along the whisker lead to whisker breakage. The microcrack between the broken whiskers can propagate into the interface or the matrix, related to the wedge angle of the broken whisker. The extrusion is beneficial to the whisker staggered and makes it easy for the microcracks filled with matrix. The whisker breakage and the whisker staggered result in the decreasing distance between the neighboring whiskers. Due to the dislocation motion constrained by matrix and the overlap of the deformation areas, the decreasing distance between the neighboring whiskers promoting the recrystallization results in the smaller grain size. During tensile tests, due to the smaller resistance with the smaller distance between the neighboring whiskers, the cracks between the progressive broken whiskers are easy to coalesce resulting in the lower ultimate tensile strength of the extruded composite.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Effects of different precursors on size and optical properties of ceria nanoparticles prepared by microwave-assisted method

Highlights: Black-Right-Pointing-Pointer A rapid and efficient microwave method was applied for synthesis of nano ceria. Black-Right-Pointing-Pointer Changing precursor has great effects on optical properties and size of nano ceria. Black-Right-Pointing-Pointer Fabrication of ceria nanoparticles using Ce{sup 4+} salts leads to better results. Black-Right-Pointing-Pointer Band gap energies of ceria nanoparticles were evaluated by UV-vis spectroscopy. -- Abstract: Cerium oxide, ceria (CeO{sub 2}), is one of the favourable nanoparticles (NPs) that possesses many remarkable properties so that it can be used in medicine, chemistry, environment, energy, information, industry, and so on. In this study, the crystalline ceria NPs were successfully prepared by an efficient microwave-assisted heating technique from an aqueous solution using different cerium salts (Ce(IV) and Ce(III) salts). The products were characterized by X-ray powder diffraction (XRD), transmission electron microscope (TEM), FTIR spectroscopy, Raman spectroscopy, and UV-vis absorption spectroscopy. The results revealed that changing the precursor led to great effects on size, band gap energy, and the reaction time of preparing the ceria NPs. The significant feature of this manuscript is that the effects of different precursors on the structural and optical properties of ceria NPs were investigated for the first time. The average particle size of different samples was below 8 nm.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Synthesis and modification of nano-sized TiO{sub 2} for photo-degradation process under visible light irradiation; a Placket–Burman experimental design

Graphical abstract: - Highlights: • Nanosized TiO{sub 2} doped with nitrogen and iron was produced by sol-gel method. • Linear models were derived to relate the phase and particle size to synthesis factors. • High photocatalytic activity was observed for acetaldehyde degradation. - Abstract: In this research, nitrogen and iron (III) co-doped nano TiO{sub 2} (N-Fe-TiO{sub 2}) was prepared by sol-gel method using ammonium chloride and iron chloride solutions as nitrogen and iron sources, respectively. The effect of synthesis parameters (weight ratios of N/TiO{sub 2} and Fe/TiO{sub 2}, synthesis temperature, calcination time and temperature) was simultaneously investigated on the quality of the N-Fe-TiO{sub 2} product by a two-level Placket–Burman experimental design. The synthesized powders were characterized by XRD, XPS and UV–Vis spectroscopy techniques. The mean crystal size and anatase content were determined and evaluated as the linear functions of so-called synthesis parameters by the statistical analysis and regression. The 2%N-1%Fe-TiO{sub 2} product by 11 nm mean crystal size and 78% anatase content, synthesized at 35 °C and calcined at 500 °C during 2 h, exhibited the most significant activity during the photo-degradation of acetaldehyde under visible light irradiation and its efficiency was obtained about four times more than photocatalytic activity of Degussa TiO{sub 2}-P25.

36 MATERIALS SCIENCE↗
DOE OSTI2013

High coercivity sized controlled cobalt–gold core–shell nano-crystals prepared by reverse microemulsion

Graphical abstract: - Highlights: • Calculating the crystallinity percentage and percentage of phases presented in Co–Au core–shell nanoparticles. • Magnetic properties of four groups nanogarin: 5, 10, 15, 20 nm. • Single domain ferromagnetic materials with high coercivity at room temperature. • Intrinsic blocking temperature measured in zero field cooled-warmed (ZFC-W). - Abstract: Size-controlled cobalt–gold core–shell nanoparticles were synthesized via the reverse-micelle microemulsion method. In order to control the size of the nanoparticles, the nucleation and growth process were performed within a confined space by adjusting the water to surfactant ratio of reverse micelles solution during synthesis. The crystallinity percentage and percentage of phases presented in Co–Au core–shell nanoparticles were calculated using X-ray diffraction data. The results from transmission electron microscopy provide direct evidence for core–shell structure nanomaterials. Magnetic properties of the samples were investigated using a vibrating sample magnetometer. The as-prepared samples showed significant coercivity at room temperature. The intrinsic blocking temperature was experimentally deduced from zero-field-cooled warmed (ZFC-W) curves by a simple method without employing an external magnetic field. The B-field dependence temperature data of Co–Au nanoparticles exhibited an intrinsic blocking temperature at 45 K. Annealing these samples at 400 °C caused an increase in particle size, crystallinity percentage and further enhanced their magnetic properties.

36 MATERIALS SCIENCE↗
DOE OSTI2013

The effects of cerium doping on the size, morphology, and optical properties of α-hematite nanoparticles for ultraviolet filtration

Highlights: • Possible application of cerium-doped α-hematite as ultraviolet filter. • Nanoparticles obtained through co-precipitation technique using various cerium doping levels followed by annealing. • Comprehensive materials characterisation utilizing XRD, DSC/TGA, STEM, UV–vis spectroscopy. • Increasing cerium content reduces particle sizing and alters morphology. • Solubility of cerium in hematite seen between 5 and 10% doping, 10% cerium doping greatly enhances attenuation in ultraviolet region and increases optical bandgap. - Abstract: Metal oxide nanoparticles have potential use in energy storage, electrode materials, as catalysts and in the emerging field of nanomedicine. Being able to accurately tailor the desirable properties of these nanoceramic materials, such as particle size, morphology and optical bandgap (E{sub g}) is integral in the feasibility of their use. In this study we investigate the altering of both the structure and physical properties through the doping of hematite (α-Fe{sub 2}O{sub 3}) nanocrystals with cerium at a range of concentrations, synthesised using a one-pot co-precipitation method. This extremely simple synthesis followed by thermal treatment results in stable Fe{sub 2−x}Ce{sub x}O{sub y} nanoceramics resulting from the burning of any unreacted precursors and transformation of goethite-cerium doped nanoparticle intermediate. The inclusion of Ce into the crystal lattice of these α-Fe{sub 2}O{sub 3} nanoparticles causes a significantly large reduction in mean crystalline size and alteration in particle morphology with increasing cerium content. Finally we report an increase optical semiconductor bandgap, along with a substantial increase in the ultraviolet attenuation found for a 10% Ce-doping concentration which shows the potential application of cerium-doped hematite nanocrystals to be used as a pigmented ultraviolet filter for cosmetic products.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Fe–Ni solid solutions in nano-size dimensions: Effect of hydrogen annealing

Highlights: • Fe–Ni solid solution with nano-size dimensions were prepared and characterized. • Both as prepared and hydrogenated solid solutions have FCC structure of Ni. • Paramagnetic and ferromagnetic domains coexist in these samples. - Abstract: Nanoparticles of Ni{sub 0.50}Fe{sub 0.50} and Ni{sub 0.75}Fe{sub 0.25} alloys were prepared by chemical reduction in ethylene glycol medium. XRD and {sup 57}Fe Mössbauer studies have confirmed the formation of Fe–Ni solid solution in nano-size dimensions with FCC structure. These samples consist of both ferromagnetic and paramagnetic domains which have been attributed to the coexistence of large and small particles as confirmed by atomic force microscopic (AFM) and {sup 57}Fe Mössbauer spectroscopic studies. Improved extent of Fe–Fe exchange interaction existing in Ni{sub 0.50}Fe{sub 0.50} alloy compared to Ni{sub 0.75}Fe{sub 0.25} alloy explains the observed increase in the relative extent of ferromagnetic domains compared to paramagnetic domains in the former sample. Increase in the relative extent of ferromagnetic domains for hydrogenated alloys is due to increase in particle size brought about by the high temperature activation prior to hydrogenation.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Influence of fatigue precracking and specimen size on Master Curve fracture toughness measurements of EUROFER97 and F82H steels

EUROFER97 and F82H steels are two leading reduced-activation ferritic-martensitic (RAFM) steels for fusion first wall and blanket applications. Exposure to the harsh environment of fusion reactors can result in severe degradation of fracture toughness. Thus, the post-irradiation evaluation of fracture toughness is critical for understanding the material behavior. Due to the space constraints of irradiation facilities and challenges in controlling a uniform irradiation condition for large size specimens, the development of small specimen test techniques (SSTT) is indispensable to evaluate the performance of irradiated materials. In this study, we evaluated specimen size effects on the Master Curve fracture toughness of EUROFER97 and F82H steels. A wide variety of specimens, including 0.5 T compact tension (C(T)) specimens, 0.16 T mini-compact tension (miniC(T)) specimens, and 1.65 mm miniature bend bar specimens, were tested. The testing methodology was based on the Master Curve method in the ASTM E1921 standard. No specimen size effect was observed in 0.5 T C(T) and 0.16 T miniC(T) specimens on the Master Curve reference temperature T0, while 1.65 mm miniature bend bar specimens yielded a higher T 0Q . A strong effect of fatigue precracking on T 0 for 0.5 T C(T) and 0.16 T miniC(T) specimens was observed, such that testing on specimens with skewed fatigue precrack fronts resulted in lower T 0 than for specimens with ASTM standard qualified straight fatigue precrack fronts. The results highlight the importance of experimental quality control in developing SSTT for Master Curve fracture toughness testing. Lastly, we also evaluated and provided recommendations on the minimum number of specimens needed for each specimen type for yielding reliable T 0Q values.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Particle size and shape effect of Crumbler® rotary shear-milled granular woody biomass on the performance of Acrison® screw feeder: A computational and experimental investigation

Physical experiments and discrete element model (DEM) simulations are conducted to evaluate particle characteristics and operation parameter effects on screw feeding performance for rotary shear-milled Douglas fir. Three performance metrics are used: mass flow rate, shaft driving torque, and specific energy consumption. The impact of particle size, particle size distribution (PSD), shaft rotational speed (rpm), and hopper dimensions on the performance are investigated. All employed performance metrics reveal the superior flowability of the 2-mm particles in contrast to the larger 6-mm counterpart. Remarkably, wider PSD results in poorer flowability than the two mono-sized particles, proving the flowability enhancement achieved by narrower PSD of the woody feedstock. More importantly, DEM simulations unveil PSD-induced degradation in flowability is attributed to mechanical interlocking and particle segregation effects. Furthermore, higher shaft rpm causes higher mass flow rate at the cost of higher specific energy consumption due to viscous dissipation and changes in flow pattern.

09 BIOMASS FUELS↗
DOE OSTI2014

Orientation influence on grain size-effects in ultrafine-grained magnesium

The mechanical behavior of ultrafine-grained magnesium was studied by discrete dislocation dynamics (DDD) simulations. Our results show basal slip yields a strong size effect, while prismatic and pyramidal slips produce a weak one. We developed a new size-strength model that considers dislocation transmission across grain boundaries. Good agreement between this model, current DDD simulations and previous experiments is observed. These results reveal that the grain size effect depends on 3 factors: Peierls stress, dislocation source strength and grain boundary strength.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Grain size effects on dislocation and twinning mediated plasticity in magnesium

Grain size effects on the competition between dislocation slip and {101¯2} -twinning in magnesium are investigated using discrete dislocation dynamics simulations. These simulations account for dislocation–twin boundary interactions and twin boundary migration through the glide of twinning dislocations. It is shown that twinning deformation exhibits a strong grain size effect; while dislocation mediated slip in untwinned polycrystals displays a weak one. In conclusion, this leads to a critical grain size at 2.7 μm, above which twinning dominates, and below which dislocation slip dominates.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Geometry and size dependent microstructure and crack formation in Rene 41 superalloy fabricated by laser powder bed fusion

This study provides a systematic investigation into the size and geometry-dependent microstructural evolution and cracking susceptibility of LPBF-fabricated Rene 41. By coupling experimental microstructural analysis with thermal modeling, this research uniquely identifies the relationship between geometry-specific thermal histories, carbide coarsening, and liquation cracking. Four different geometries with varying thickness were fabricated with the identical process parameters. It was found that the grain size and morphology are not affected by the part size. However, the thinner parts exhibited coarser sub-grain structures compared to the thicker ones. The crack formation was observed for the parts with cross-sections smaller than 1 mm, whereas thicker parts had high density without any defects. Further, the cracks were observed in the interdendritic regions, suggesting that liquation cracking was the active micro-crack formation mechanism. The detailed microstructural analysis combined with a thermal finite element analysis proved that the heat extraction efficiency was lower for thinner parts causing a lower cooling rate and coarser carbides, making them more susceptible to constitutional liquation. Microhardness measurements were conducted for each geometry and correlated with the observed microstructural variations. The findings highlight the critical need for geometry-specific optimization of LPBF process parameters to mitigate cracking and achieve microstructural uniformity, offering valuable insights into the fabrication of complex, high-performance aerospace components.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Statistical analysis of support thickness and particle size effects in HRTEM imaging of metal nanoparticles

High-resolution transmission electron microscopy (HRTEM) examination of nanoparticles requires their placement on some manner of support – either TEM grid membranes or part of the material itself, as in many heterogeneous catalyst systems – but a systematic quantification of the practical imaging limits of this approach has been lacking. Here, in this paper, we address this issue through a statistical evaluation of how nanoparticle size and substrate thickness affects the ability to resolve structural features of interest in HRTEM images of metallic nanoparticles on common support membranes. The visibility of lattice fringes from crystalline Au nanoparticles on amorphous carbon and silicon supports of varying thickness was investigated with both conventional and aberration-corrected TEM. Over the 1–4 nm nanoparticle size range examined, the probability of successfully resolving lattice fringes differed significantly as a function both of nanoparticle size and support thickness. Statistical analysis was used to formulate guidelines for the selection of supports and to quantify the impact a given support would have on HRTEM imaging of crystalline structure. For nanoparticles ≥1 nm, aberration-correction was found to provide limited benefit for the purpose of visualizing lattice fringes; electron dose is more predictive of lattice fringe visibility than aberration correction. These results confirm that the ability to visualize lattice fringes is ultimately dependent on the signal-to-noise ratio of the HRTEM images, rather than the point-to-point resolving power of the microscope. Lastly, this study provides a benchmark for HRTEM imaging of crystalline supported metal nanoparticles and is extensible to a wide variety of supports and nanostructures.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Influence of moisture content, particle size and forming temperature on productivity and quality of rice straw pellets

Highlights: • Optimized conditions were determined for the production of rice straw pellets. • The moisture content and forming temperature are key factors. • High quality rice pellets in the lower heating value and durability were produced. - Abstract: A large amount of rice straw is generated and left as much in paddy fields, which causes greenhouse gas emissions as methane. Rice straw can be used as bioenergy. Rice straw pellets are a promising technology because pelletization of rice straw is a form of mass and energy densification, which leads to a product that is easy to handle, transport, store and utilize because of the increase in the bulk density. The operational conditions required to produce high quality rice straw pellets have not been determined. This study determined the optimal moisture content range required to produce rice straw pellets with high yield ratio and high heating value, and also determined the influence of particle size and the forming temperature on the yield ratio and durability of rice straw pellets. The optimal moisture content range was between 13% and 20% under a forming temperature of 60 or 80 °C. The optimal particle size was between 10 and 20 mm, considering the time and energy required for shredding, although the particle size did not significantly affect the yield ratio and durability of the pellets. The optimized conditions provided high quality rice straw pellets with nearly 90% yield ratio, ⩾12 MJ/kg for the lower heating value, and >95% durability.

09 BIOMASS FUELS↗
DOE OSTI2017

Theoretical Analysis of Photoelectron Spectra of Pure and Mixed Metal Clusters: Disentangling Size, Structure, and Composition Effects

A theoretical/computational description and analysis of the spectra of electron binding energies of Al 12 - , Al 13 - and Al 12 Ni- clusters, which differ in size and/or composition by a single atom yet possess strikingly different measured photoelectron spectra, is presented. It is shown that the measured spectra can not only be reproduced computationally with quantitative fidelity – this is achieved through a combination of state-of-the-art density functional theory with a highly accurate scheme for conversion of the Kohn-Sham eigenenergies into electron binding energies – but also explained in terms of the effects of size, structure/symmetry and composition. Furthermore, a new methodology is developed and applied that provides for disentanglement and differential assignment of the separate roles played by size, structure/symmetry and composition in defining the observed differences in the measured spectra. The methodology is general and applicable to any finite system, homogeneous or heterogeneous. Finally, we project that in combination with advances in synthesis techniques this methodology will become an indispensable computation-based aid in the design of controlled synthesis protocols for manufacture of nanosystems and nanodevices with precisely desired electronic and other characteristics.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Aggregation of Size-Selected Oxide Clusters Deposited onto Au(111)

Kinetic Monte Carlo (kMC) simulations along with density functional theory (DFT) calculations were used to investigate the aggregation of size-selected Nb 3 O y (y = 5, 6, 7) clusters deposited onto the Au(111) surface. Recent STM experiments showed that the cluster binding sites and sizes of the cluster assemblies on the Nb 3 O y /Au(111) surfaces strongly depend on the stoichiometry of the clusters, i.e., the oxygen-to-niobium ratio. To better understand the origins of these differences, kMC simulations of the nucleation and growth of cluster assemblies were performed using energy barriers for diffusion and intercluster interactions estimated from DFT calculations of cluster binding and dimerization energies, respectively. Comparisons of the kMC simulations with STM images of the as-deposited Nb 3 O y /Au(111) surfaces at RT and after high temperature annealing were used to further optimize the energetics and gauge the importance of nearest neighbor interactions. The kMC simulations demonstrate that the assembly of Nb 3 O y clusters on Au(111) are largely controlled by the magnitude of the barriers for diffusion and interparticle-bond formation, while changes at higher temperatures are sensitive to the binding energies between nearest neighbors. Simulations for the Nb 3 O 5 and Nb 3 O 6 clusters, which exhibit smaller cluster assembly sizes in STM, required larger diffusion barriers as well as different barriers for interparticle binding, which reflected differences in DFT calculated dimerization energies. Furthermore, the results demonstrate the effectiveness of combined DFT and kMC calculations for understanding how the stoichiometry affects the aggregation of small oxide clusters on a metal surface.

36 MATERIALS SCIENCE↗
DOE OSTI2023

In Situ Raman Mapping of Si Island Electrodes and Stress Modeling as a Function of Lithiation and Size

Si is known for cracking and delamination during electrochemical cycling of a battery due to the large volume change associated with Li insertion and extraction. However, it has been found experimentally that patterned Si island electrodes that are 200 nm thick and less than 7 μm wide can deform in a purely elastic manner. Inspired by this, we performed in situ Raman stress characterization of model poly-crystalline Si island electrodes using an electrochemical cell coupled with an immersion objective lens and designed for a short working distance. A 5 μm wide Si island electrode showed a parabolic stress profile during lithiation, while for a 15 μm Si island electrode, a stress plateau in the center of the electrode was observed. A continuum model with coupled electro-chemo-mechanical (ECM) physics was established to understand the stress measurement. A qualitative agreement was reached between modeling and experimental data, and the critical size effect could be explained by the Li diffusive flux as governed by competition between the Li concentration and hydrostatic stress gradients. Below the critical size, the stress gradient drives Li toward the edges, where the electrode volume is free to expand, while above the critical size, the stress plateau inhibits Li diffusion to the edge and forces destructive stress relief by cracking. Furthermore, this work represents a promising methodology for in situ characterization of ECM coupling in battery electrodes, with suggestions provided for further improvement.

25 ENERGY STORAGE↗
DOE OSTI2023

Calorimetric Energies and Chemical Potentials of Metal Atoms in Catalytic Nanoparticles on Oxide and Carbon Supports: Improved Size Dependencies and Adhesion Energies

The chemical potential of metal atoms, μM, in supported metal nanoparticles is an important descriptor related to both the catalytic activity and the stability of the nanoparticles. Here, we derive an expression relating μM to the radius of the particle’s contact area with the support and the adhesion energy at the metal/support interface (E adh ) that assumes the particles have the shape of spherical caps but of arbitrary contact angle with the support (θ c ) and includes an empirical correction for the increase in metal surface energy and adhesion energy with decreasing radius of curvature. We then show that, at any assumed contact angle, we can simultaneously fit previously reported measurements of both calorimetric μ M (from heats of metal vapor adsorption during nanoparticle growth by vapor deposition) versus metal coverage data and the He + low-energy ion scattering (LEIS) intensities for the metal and/or support versus metal coverage (using our recently developed spherical cap model for quantitative LEIS intensities), to determine the particle size versus coverage and E adh . Only one choice of contact angle gives a pair of values for contact angle and E adh , which is consistent with the Young–Dupré equation for the equilibrium shape of a spherical particle. At this equilibrium shape, we then applied this spherical cap model (SCM) to reanalyze microcalorimetric metal chemical potentials and LEIS signals versus coverage data for nine metal/support combinations that were previously analyzed by assuming that the particles had the shape of hemispherical caps, i.e., with a contact angle of 90°. We show that this revised approach gives close agreement with the calorimetric and LEIS data; the best-fit contact angles vary from 64 to 84°, correcting the earlier assumption of 90°. Furthermore, these results provide significant accuracy improvements in particle size versus coverage, metal chemical potential versus size and coverage, metal/support adhesion energies and contact angles for Cu, Ag and Au on CeO 2 (111), Ni on MgO(100), Ag on Fe 3 O 4 (111) and TiO 2 (100), and Ag, Ni and Pd on Ni-supported graphene. This revised approach is much more broadly applicable than the earlier hemispherical cap model (HCM).

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2017

Chemical Potential of Metal Atoms in Supported Nanoparticles: Dependence upon Particle Size and Support

Metal nanoparticles supported on oxide surfaces form the basis for many industrial catalysts and promise to play an ever-increasing role in future energy and environmental technologies. The chemical potential (μ) of the metal atoms in these particles depends strongly on particle size and support and is an important factor that determines their catalytic properties, including their binding strengths to adsorbed reaction intermediates and their long-term stability against sintering. We present here a method for estimating this chemical potential as a function of particle size for different metal/oxide combinations. We show that this chemical potential for late transition metals is well approximated for a particle of diameter D by μ( D ) = [(3γ m – E adh )(1 + D o / D )](2 V m / D ), where γ m is the surface energy of the bulk metal, E adh is the adhesion energy at the bulk metal/oxide interface, and D o is ~1.5 nm, and V m is the molar volume of the bulk metal. We further show that E adh increases with (1) increasing heat of formation of the most stable oxide of the metal from metal gas atoms plus O 2 (gas) per mole of metal atoms, (2) decreasing enthalpy of reduction of the oxide to its next lower oxidation state plus O 2 (gas), per mole of oxygen atoms, and (3) increasing density of surface oxygen atoms on the oxide surface. The linear scaling of E adh with these properties allows estimations of E adh for a variety of metal/oxide combinations. Using this E adh estimate in the above equation with known values for γ m allows estimates of metal chemical potential versus particle size for late transition metals on various oxide supports. WE conclude this will improve our ability to understand structure–property relations in catalysis and design better catalysts.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗