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At least 1,729 records · Page 96
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Eu3B2Pt7 by Materials Project

Eu3Pt7B2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent Eu+2.67+ sites. In the first Eu+2.67+ site, Eu+2.67+ is bonded in a 12-coordinate geometry to twelve Pt2- atoms. There are a spread of Eu–Pt bond distances ranging from 3.29–3.36 Å. In the second Eu+2.67+ site, Eu+2.67+ is bonded to twelve equivalent Pt2- atoms to form EuPt12 cuboctahedra that share edges with six equivalent EuPt12 cuboctahedra, edges with six equivalent PtEu6Pt6 cuboctahedra, and faces with six equivalent BPt6 pentagonal pyramids. All Eu–Pt bond lengths are 3.20 Å. There are two inequivalent Pt2- sites. In the first Pt2- site, Pt2- is bonded in a distorted L-shaped geometry to five Eu+2.67+, one Pt2-, and two equivalent B3+ atoms. The Pt–Pt bond length is 2.86 Å. There are one shorter (2.20 Å) and one longer (2.25 Å) Pt–B bond lengths. In the second Pt2- site, Pt2- is bonded to six equivalent Eu+2.67+ and six equivalent Pt2- atoms to form PtEu6Pt6 cuboctahedra that share corners with six equivalent BPt6 pentagonal pyramids, edges with six equivalent EuPt12 cuboctahedra, edges with six equivalent PtEu6Pt6 cuboctahedra, and faces with two equivalent BPt6 pentagonal pyramids. B3+ is bonded to six equivalent Pt2- atoms to form distorted BPt6 pentagonal pyramids that share corners with three equivalent PtEu6Pt6 cuboctahedra, edges with three equivalent BPt6 pentagonal pyramids, a faceface with one PtEu6Pt6 cuboctahedra, and faces with three equivalent EuPt12 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on USnPt2 by Materials Project

UPt2Sn crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. U is bonded to six equivalent Pt atoms to form edge-sharing UPt6 octahedra. All U–Pt bond lengths are 2.83 Å. Pt is bonded in a 6-coordinate geometry to three equivalent U and three equivalent Sn atoms. There are one shorter (2.80 Å) and two longer (2.81 Å) Pt–Sn bond lengths. Sn is bonded in a 6-coordinate geometry to six equivalent Pt atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pt3Cl3F by Materials Project

Pt3Cl3F crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Pt+1.33+ is bonded to four equivalent Cl1- and two equivalent F1- atoms to form a mixture of edge and corner-sharing PtCl4F2 octahedra. The corner-sharing octahedral tilt angles are 0°. All Pt–Cl bond lengths are 2.51 Å. Both Pt–F bond lengths are 2.51 Å. Cl1- is bonded in a square co-planar geometry to four equivalent Pt+1.33+ atoms. F1- is bonded to six equivalent Pt+1.33+ atoms to form corner-sharing FPt6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Influence of Cs Loading on Pt/m-ZrO 2 Water–Gas Shift Catalysts

Certain alkali metals (Na, K) at targeted loadings have been shown in recent decades to significantly promote the LT-WGS reaction. This occurs at alkali doping levels where a redshift in the C-H band of formate occurs, indicating electronic weakening of the bond. The C-H bond breaking of formate is the proposed rate-limiting step of the formate associative mechanism, lending support to the occurrence of this mechanism in H2-rich environments of the LT-WGS stage of fuel processors. Continuing in this vein of research, 2%Pt/m-ZrO 2 was promoted with various levels of Cs in order to explore its influence on the rate of formate intermediate decomposition, as well as that of LT-WGS in a fixed bed reactor. In situ DRIFTS experiments revealed that Cs promoter loadings of 3.87% to 7.22% resulted in significant acceleration of the forward formate decomposition in steam at 130 °C. Of all of the alkali metals tested to date, the redshift in the formate ν(CH) band with the incorporation of Cs was the greatest. XANES difference experiments at the Pt L 2 and L 3 edges indicated that the electronic effect was not likely due to an enrichment of electronic density on Pt. CO 2 TPD experiments revealed that, unlike Na and K promoters, Cs behaves more like Rb in that the decomposition of the second intermediate in LT-WGS, carbonate species, is hindered due to (1) increased basicity of Cs, (2) the tendency of Cs to cover Pt sites that facilitate CO 2 decomposition, and (3) the tendency of Cs to increase Pt particle size as shown by EXAFS results, resulting in fewer Pt sites that facilitate CO2 decomposition. As such, the LT-WGS rate was hindered overall and the rate-limiting step shifted to carbonate decomposition (CO 2 removal). Like its Rb counterpart, low levels of added Cs (e.g., 0.72%Cs) were found to improve the stability of the catalyst relative to the unpromoted catalyst; the stability comparison was made at similar CO conversion level as well as similar space velocity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Constructing Highly Durable Fuel Cell Catalysts Through Integrating Graphitic Shell‐Protected Composite Carbon Support with Gaseous Co Deposition‐Driven PtCo Intermetallics

Metal dissolution, nanoparticle agglomeration, and carbon support corrosion cause significant performance degradation of current PtCo catalysts under acidic and oxidative oxygen reduction reaction. Here, in this study, an integrated strategy is presented to design high-performance Pt 3 Co intermetallic catalysts by regulating gaseous Co deposition-driven diffusion into Pt nanoparticles supported on a composite carbon. The composite carbon is derived from ZIF-8/polyaniline, consisting of a high-surface-area (HSC) core and a protective graphitic shell (GS), which is employed to design 40 wt.% Pt/HSC@GS catalyst. The corresponding membrane electrode assemblies (MEAs) can maintain 1.09 A cm −2 at 0.7 V (20. 7% loss) after 10 000 cycles (1.0–1.5 V for carbon stability) and 1.15 A cm −2 (16.1% loss) after 150 000 cycles (0.60–0.95 V for catalyst stability). A ordered Pt 3 Co intermetallic is synthesized via a gaseous Co-deposition process, which yields a homogeneous Co-rich layer onto the Pt nanoparticles on the composite support, thereby facilitating Co diffusion into Pt crystal during subsequent ordering annealing to form the ordered intermetallic structure. This gaseous deposition leads to a thin carbon layer on PtCo nanoparticles, inhibiting particle growth during the annealing and mitigating Co dissolution under dynamic electrochemical conditions. The PtCo catalyst achieves impressive MEA performance and long-term durability (1.45 A cm −2 at 0.7 V after 120 000 cycles) under heavy-duty conditions.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2020

Biaxial Strains Mediated Oxygen Reduction Electrocatalysis on Fenton Reaction Resistant L1 0 ‐PtZn Fuel Cell Cathode

Abstract PtM alloy catalysts (e.g., PtFe, PtCo), especially in an intermetallic L1 0 structure, have attracted considerable interest due to their respectable activity and stability for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). However, metal‐catalyzed formation of ·OH from H 2 O 2 (i.e., Fenton reaction) by Fe‐ or Co‐containing catalysts causes severe degradation of PEM/catalyst layers, hindering the prospects of commercial applications. Zinc is known as an antioxidant in Fenton reaction, but is rarely alloyed with Pt owing to its relatively negative redox potential. Here, sub‐4 nm intermetallic L1 0 ‐PtZn nanoparticles (NPs) are synthesized as high‐performance PEMFC cathode catalysts. In PEMFC tests, the L1 0 ‐PtZn cathode achieves outstanding activity (0.52 A mg Pt −1 at 0.9 V iR ‐free , and peak power density of 2.00 W cm −2 ) and stability (only 16.6% loss in mass activity after 30 000 voltage cycles), exceeding the U.S. DOE 2020 targets and most of the reported ORR catalysts. Density function theory calculations reveal that biaxial strains developed upon the disorder‐order (A1L1 0 ) transition of PtZn NPs would modulate the surface PtPt distances and optimize PtO binding for ORR activity enhancement, while the increased vacancy formation energy of Zn atoms in an ordered structure accounts for the improved stability.

Liang, Jiashun↗
DOE OSTI2024

In situ Formation of Platinum-Carbon Catalysts in Propane Dehydrogenation

The catalytic production of propylene via propane dehydrogenation (PDH) is a key reaction in the chemical industry. By combining operando transmission electron microscopy with density functional theory analysis, we show that the intercalation and ordering of carbon on Pt interstitials to form Pt-C solid solutions is relevant for increasing propylene production. More specifically, we found that at the point of enhanced propylene formation, the structure of platinum nanoparticles is transformed into a transient caesium chloride-type Pt-C polymorph. At more elevated temperatures, the zincblende and rock salt polymorphs seemingly coexist. When propylene production was highest, multiple crystal structures consisting of Pt and carbon were occasionally found to coexist in one individual nanoparticle, distorting the Pt lattice. Catalyst coking was detected at all stages of the reaction, but did initially not affect all particles. These findings could lead to the development of novel synthesis strategies towards tailoring highly efficient PDH catalysts.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Regulating catalyst and ionomer interactions to promote oxygen transport in fuel cells

The cost of proton exchange membrane fuel cells (PEMFCs) has been a major impediment to their widespread commercialization. Reducing platinum (Pt) usage in PEMFC represents an essential step in lowering the cost. However, decreasing Pt loading in the cathode catalyst layer (CCL) often leads to a significant increase in the local oxygen transport resistance (R Local ), which not only slows the oxygen reduction reaction but also causes a higher polarization overpotential. The poisoning of Pt by perfluorosulfonic acid ionomers also becomes more predominant at low Pt loadings. Therefore, regulating catalyst and ionomer interactions by optimizing their interface in the CCL is crucial to improving PEMFC performance. Here, in this review, the strategies of improving oxygen transport by controlling Pt-ionomer interactions and interfaces through catalyst design, ionomer structure, and incorporation of additives are summarized. Finally, perspectives on future optimization of catalyst and ionomer interactions are proposed.

25 ENERGY STORAGE↗
DOE OSTI2022

A facile approach for site-selective and large-area growth of MoS 2 through heterogeneous nucleation

Heterogeneous nucleation could be an effective approach to producing an array of transition metal dichalco-genides (TMDs) at controlled locations on a substrate. In this study, we prepared Pt mesa structures on the substrate to induce heterogeneous nucleation of MoS 2 during chemical vapor deposition (CVD) and investigated the adsorption of nuclei using Monte Carlo (MC) simulations. The MC simulations suggest that the site-selectivity of MoS 2 dramatically drops when the CVD growth time goes beyond the critical time at which nuclei fully cover the Pt mesas, and such critical time can be delayed when the size of Pt mesas increases. Our experimental observations on a clean array of MoS 2 successfully synthesized on 10 um-width square Pt mesas but not on 4 um -width square Pt mesas support the MC simulation. We further designed a simple method employing dummy substrates to increase the yield of the site-selective MoS 2 array. Computational fluid dynamics (CFD) simulation reveals that such dummy substrates restrict the precursor concentration and provide a confined channel for the precursors to react slowly, which benefits producing large-area and site-selective MoS 2 . Furthermore, compared with conventional CVD, the total coverage of site-selective MoS 2 has enlarged by seven times using dummy substrates.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Optimizing the lean hydrocarbon NO x trap: Sequential and dual-layer configurations

Vehicular emission control catalysts are ineffective in eliminating CO, hydrocarbons, and NO x during engine cold-start when exhaust temperatures are below 200 °C. In this study the performance of coupled low temperature NO x , n-C 12 H 26 (C 12 ), and C 3 H 6 trapping, release and conversion for a series of model Lean Hydrocarbon NO x Trap (LHCNT) catalysts are examined. Pd and Pt supported on small-pore (SSZ-13) and large-pore (BEA) zeolites are selected based on the performance during transient NO and C 12 uptake, release and conversion experiments. These catalysts are combined into sequential (Pt + Pd/BEA → Pd/SSZ-13; Pd/SSZ-13 → Pt + Pd/BEA) and dual-layer (Pt + Pd/BEA top, Pd/SSZ-13 bottom) configurations in an attempt to improve the trapping and conversion performance. While all three configurations trap between 75 and 100 μmolNO x /g-cat, the Pd/SSZ-13 → Pt + Pd/BEA sequential configuration is most effective in simultaneously trapping C 12 and NO in the presence of H 2 O, resulting in excellent NO and C 12 storage below 100 °C with release and/or conversion at or above 200 °C. For each configuration, C 12 oxidation lights-off below 300 °C and NO oxidation achieves ~35 % conversion in the absence of C 12 . Neither the presence of C 12 nor the order of the sequential configuration has a significant impact on NO uptake. C 12 significantly delays NO and NO 2 desorption to temperatures exceeding 300 °C. The more compact dual-layer catalyst is most effective in forming NO 2 as the release temperature lines up with the maximum NO conversion temperature but traps less C 12 than the sequential configurations. The addition of C 3 H 6 in the feed on the dual-layer catalyst leads to further delay in the NO x desorption as well as increased NO and C 12 conversion at high temperatures. Here, the overall findings provide guidance in the optimizing LHCNT configuration for realistic feeds.

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

Designing ultrastable Pt/CeO 2 -Al 2 O 3 nanosheet catalysts for three-way catalysts applications

Designing Rh-free, especially Pt-only, three-way catalysts with improved low-temperature activity/stability is highly desirable. Herein, we demonstrate that ultrastable Pt/CeO 2 -Al 2 O 3 nanosheet catalysts can be obtained based on a Sabatier principle of metal-support interaction. Tuning the surface coverage of penta-site rich γ-Al 2 O 3 nanosheets (AlNS, weak adhesion to Pt) by CeO 2 “nano-islands” (strong adhesion to Pt) can lead to the synthesis of Pt/60 wt.%CeO 2 -AlNS that have lower light-off temperatures for CO, hydrocarbons, and NO compared to conventional Pt/CeO 2 and Pt/Al 2 O 3 catalysts by 100–200°C and a similar performance with the state-of-the-art Rh-based catalyst. Further, incorporating CeO 2 on the surface of AlNS can retard the sintering of CeO 2 during harsh redox hydrothermal aging, associate with the strong interaction between CeO 2 “nano-island” and penta-site rich γ-Al 2 O 3 nanosheets. Moreover, the improved activity/stability of Pt/CeO 2 -AlNS catalysts can be attributed to tuning of the Pt detachment and migration from and back to the CeO 2 “nano-islands”, respectively, that keeps Pt as nanoclusters on CeO 2 , the most active species for three-way catalyst applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Structure sensitivity of ammonia electro-oxidation on transition metal surfaces: A first-principles study

Ammonia electro-oxidation is a promising catalytic reaction for application in alkaline fuel cells. In this paper we study the trends in this reaction on the (1 0 0) facet of eight fcc transition metals: Au, Ag, Cu, Pt, Pd, Ni, Ir, and Rh. We calculate from first-principles (DFT-GGA-PW91) the energetics for two mechanisms: (i) the N + N mechanism and (ii) the Gerischer-Mauerer mechanism. The onset potentials for both mechanisms are provided for both (1 0 0) and (1 1 1) facets. We also calculate the activation energies for the N-N bond-making non-Faradaic events on Cu, Pt, Pd, Ni, Ir, and Rh. We discover that N* – which is considered a poison for Pt(1 1 1) – is a reactive intermediate on Pt(1 0 0), allowing for a facile dimerization to N2 on Pt(1 0 0) at high potentials. We draw similar analyses for the structure sensitivity on the other metals, and we conclude with some general principles to guide catalyst design for this reaction.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Thermodynamics and kinetics of interconversion between platinum nanoparticles and cations in zeolites

In metal-containing zeolites, sintering and redispersion processes exercise control over the identity of metal site structures, but the thermodynamic and kinetic factors that influence these molecular-level processes are not completely understood. Furthermore, we assess the ability of first principles informed free energy models (for supported and unsupported nanoparticles) and kinetic models integrating Ostwald ripening with atom trapping to describe the interconversion between Pt cations and nanoparticles encapsulated in chabazite (CHA) zeolites. Density functional theory-derived thermodynamic phase diagrams show that the interconversion between cations, favored in oxidizing environments, and particles, favored in reducing environments, is fully reversible within a wide range of their respective conditions (temperatures and pressures) for CHA and several other zeolite topologies. Kinetic Monte Carlo simulations of Pt redispersion are consistent with experimentally observed redispersion kinetics of encapsulated Pt nanoparticles in CHA zeolites, and model results suggest the zeolite host imparts additional stability for Pt nanoparticles. We envision our thermodynamic and kinetic models for Pt-CHA are also capable of describing nanoparticle and cation interconversions for other zeolite frameworks under similar conditions.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Tailoring electrode microstructure via ink content to enable improved rated power performance for platinum cobalt/high surface area carbon based polymer electrolyte fuel cells

Improvements in polymer electrolyte fuel cell (PEFC) electrode performance have primarily focused on catalyst and ionomer developments, marginalizing the importance of catalyst ink formulation. In this study, the effect of ink formulation is examined across a series of cathodes comprised of PtCo supported on high surface area carbon (PtCo/ HSC ) and Nafion ionomer using an array of in situ electrochemical and ex situ characterization techniques. In contrast to prior work on Pt/Vu systems, ink water content had little effect on the electrochemically determined ionomer coverage for the PtCo/HSC electrocatalyst examined here. Characterization using nano-scale resolution X-ray computed tomography (nano-CT) demonstrated that water-rich ink formulations lead to a reduction in aggregate size (ionomer + PtCo/HSC), improving local O 2 transport. This understanding, combined with the use of a commercially-available electrocatalyst was used to produced state-of-the-art membrane electrode assemblies with Pt loadings of 0.03/0.08 mg Pt /cm 2 on the anode and cathode respectively, having; i) > 1 A/mg Pt (0.9 V iR-free , 150 kPa, 80 °C, 100% RH, H 2 /O 2 ), ii) 320 mA/cm 2 at 0.8 V, 150 kPa, 80 ° C, 100% RH, H 2 /Air), and iii) > 1 W/cm 2 elec at rated power (0.67 V, 250 kPa, 94 °C, 65% RH, H 2 /Air) or < 0.11 g Pt /kW rated .

25 ENERGY STORAGE↗
DOE OSTI2023

Amino-tethering synthesis strategy toward highly accessible sub-3-nm L1 0 -PtM catalysts for high-power fuel cells

Because of the poor accessibility of embedded active sites, platinum (Pt)-based electrocatalysts suffer from insufficient Pt utilization and mass transport in membrane electrode assemblies (MEAs), limiting their performance in polymer electrolyte membrane fuel cells. Here, we report a simple and universal approach to depositing sub-3-nm L1 0 -PtM nanoparticles over external surfaces of carbon supports through pore-tailored amino (NH 2 )-modification, which enables not only excellent activity for the oxygen reduction reaction, but also enhanced Pt utilization and mass transport in MEAs. Using a low loading of 0.10 mg Pt ∙cm -2 , the MEA of PtCo/KB-NH 2 delivered an excellent mass activity of 0.691 A∙mgPt -1 , a record-high power density of 0.96 W∙cm -2 at 0.67 V, and only a 30-mV drop at 0.80 A∙cm -2 after 30,000 voltage cycles, which meets nearly all targets set by the Department of Energy. Finally, this work provides an efficient strategy for designing advanced Pt-based electrocatalysts and realizing high-power fuel cells.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2024

Influence of zwitterionic amphiphilic copolymers on heterogeneous gypsum formation: A promising approach for scaling resistance

Here, this study aims to investigate the influence of zwitterionic amphiphilic copolymers (ZACs) in the nucleation and growth of heterogeneous CaSO4 at the zwitterion-water interface, which is crucial for the prevention of mineral scaling and consequent downtime or suboptimal performance in industries like membrane desalination, heat exchangers, and pipeline transportation. In situ grazing incidence small angle X-ray Scattering (GISAXS), and quartz crystal microbalance with dissipation (QCM-D) techniques were used to analyze the evolution of CaSO 4 particles on two new ZAC coatings: poly-(trifluoroethyl methacrylate-random-sulfobetaine methacrylate) (PTFEMA-r-SBMA, or PT:SBMA) and poly(trifluoroethyl methacrylate-random-2-methacryloyloxyethyl phosphorylcholine) (PTFEMA-r-MPC, or PT:MPC). The results showed that PT:MPC coatings promoted nucleation but inhibited crystal growth, resulting in slower overall reaction kinetics on PT:MPC coatings compared to PT:SBMA coatings. Interfacial interactions involving the substrates, sulfate minerals, and ions were examined, revealing that calcium ion adsorption, primarily governed by electrostatic attraction, played a crucial role in the nucleation and growth processes on both ZAC coatings. The crystal characterization revealed a phase transition from bassanite to gypsum on both ZAC coatings, suggesting that these zwitterionic materials can influence the mineral phase of heterogeneously formed CaSO 4 crystals. These findings enhance our understanding of the fundamental mechanisms underlying heterogeneous CaSO 4 scaling in the presence of zwitterionic materials.

42 ENGINEERING↗
DOE OSTI2024

A DFT Comparison of C–C Reductive Coupling from Terminal Cyanido and Cyaphido Complexes of Nickel

The density functional theory study of the thermal C–C reductive coupling from terminal cyanido and hypothetical cyaphido complexes of [Ni(dmpe)] (dmpe = 1,2-bis(dimethylphosphino)ethane) revealed the key reaction intermediate in the reductive C–CP coupling being a σ-CC complex unlike an η 2 -aryl complex in the Ni C–CN system, as already observed in our previous studies. The reaction in THF is endothermic by 4.9 kcal/mol for cyanido with a 32.0 kcal/mol activation barrier and exothermic by 28.5 kcal/mol for cyaphido with an 11.3 kcal/mol activation barrier. To compare our results with the existing experimental data, we chose mesityl as the aryl group and also studied the CP reaction with [Pt(dmpe)] and [Pt(dmpm)] (dmpe = 1,2-bis(dimethylphosphino)methane) fragments. Our findings are consistent with the thermodynamically uphill photolytic C–CP bond activation in phosphaalkynes with Pt and a faster thermal back-reaction with [Pt(dmpe)] compared to that of [Pt(dmpm)]. Furthermore, based on the natural population analysis, when the polarity of the C–C bond is inverted, the sign of ΔG° is also inverted.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Trends in Formic Acid Electro-Oxidation on Transition Metals Alloyed with Platinum and Palladium

Direct formic acid fuel cells (DFAFCs) have emerged as a promising power source to meet increased demands for alternative energy sources in the transportation and portable energy storage sectors. Furthermore, these fuel cells utilize formic acid (FA), a nontoxic and carbon-neutral fuel when produced from biomass or via CO 2 reduction. Despite the promise of DFAFCs, the best monometallic catalysts, platinum and palladium, are poisoned by CO through the indirect oxidation pathway and require large overpotentials. By alloying Pt and Pd with other metals, we aim to improve both the activity and selectivity of these catalysts. Here, we present a systematic density functional theory (GGA-PW91) study of FA electro-oxidation (FAO) on the (111) facet of bimetallic Pt (Pt 3 M) or Pd (Pd 3 M) catalysts (M = Au, Ag, Cu, Pt, Pd, Ir, Rh, Ru, or Re) to evaluate the catalytic performance of these surfaces. For each surface, we calculate free energy diagrams and onset potentials of three key reaction mechanisms: direct oxidation of FA via carboxyl (COOH), direct oxidation of FA via formate (HCOO), and the indirect oxidation of FA that first forms CO en route to full oxidation to CO 2 . We then display the trends in the form of phase diagrams that compare the activity of the calculated surfaces against regions of high activity using the free energies of adsorbed CO and OH as descriptors, enabling high-throughput screening and design of improved catalysts, particularly those alloying Pt or Pd with Ir, Ru, or Re.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗