The effect of modifying Pd/Al2O3 catalysts by atomic layer deposition 1 nm ZrO2 films was studied. For on oxidized, PdO/Al2O3 catalysts, TEM imaging, EDS mapping, and metal-dispersion measurements confirmed the presence thin over both Al2O3 support metal particles. were surprisingly stable, forming a well-crystallized phase only above 1173 K. coating PdO particles created semicore–shell-like structure that stabilized against sintering in air at 1073 Steady-state, methane oxidation rates...

The concept of self-regenerating or "smart" catalysts, developed to mitigate the problem supported metal particle coarsening in high-temperature applications, involves redispersing large particles by incorporating them into a perovskite-structured support under oxidizing conditions and then exsolving as small reducing conditions. Unfortunately, redispersion process does not appear work practice because surface areas perovskite supports are too low diffusion lengths for ions within bulk...

Atomic layer deposition (ALD) offers exciting possibilities for controlling the structure and composition of surfaces on atomic scale in heterogeneous catalysts solid oxide fuel cell (SOFC) electrodes. However, while ALD procedures equipment are well developed applications involving flat surfaces, conditions required porous materials with a large surface area need to be very different. The (e.g., rare earths other functional oxides) that interest catalytic will also For rapid cycling,...

Precise control of electron density at catalyst active sites enables regulation surface chemistry for the optimal rate and selectivity to products. Here, an ultrathin catalytic film amorphous alumina (4 nm) was integrated into a condenser device that enabled tunable depletion from layer correspondingly stronger Lewis acidity. The had following structure: alumina/graphene/HfO2 dielectric (70 nm)/p-type Si. Application positive voltages up +3 V between graphene p-type Si resulted in electrons...

Accelerating catalytic chemistry and tuning surface reactions require precise control of the electron density metal atoms. In this work, nanoclusters platinum were supported on a graphene sheet within condenser device that facilitated or hole accumulation in active sites with negative positive applied potential, respectively. The was fabricated by depositing top p-type Si wafer an amorphous HfO2 dielectric (70 nm), which placed layer 2-4 nm graphene. A potential ±6 V to Pt/graphene relative...

Catalytic condensers composed of ion gels separating a metal electrode from platinum-on-carbon active layer were fabricated and characterized to achieve more powerful, high surface area dynamic heterogeneous catalyst surfaces. Ion comprised poly(vinylidene difluoride)/1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide spin coated as 3.8 μm film on Au surface, after which carbon sputtering 1.8 nm electron-beam evaporation 2 Pt clusters created an exposed reactant gases. Electronic...

Catalytic condensers stabilize charge on either side of a high-k dielectric film to modulate the electronic states catalytic layer for control surface reactions. Here, carbon sputtering provided fast, large-scale fabrication metal–carbon required industrial application. Carbon films were sputtered HfO2 dielectric/p-type Si with different thicknesses (1, 3, 6, and 10 nm), enhancement conductance capacitance was observed upon increasing thickness following thermal treatment at 400 °C. After Pt...

Composite, Solid-Oxide-Fuel-Cell (SOFC) electrodes of La0.8Sr0.2FeO3 (LSF) and yttria-stabilized zirconia (YSZ) were prepared by infiltration methods then modified Atomic Layer Deposition (ALD) ZrO2, La2O3, Fe2O3, or La2O3-Fe2O3 codeposited films different thicknesses to determine the effect surface composition on cathode performance. Film growth rates for ALD performed using vacuum procedures at 573 K Fe2O3 523 ZrO2 La2O3 determined be 0.024 nm ZrO2/cycle, 0.019 La2O3/cycle, 0.018...

A series of ZrO2-supported WOx catalysts were prepared using atomic layer deposition (ALD) with W(CO)6, and then compared to a WOx/ZrO2 catalyst via conventional impregnation. The types sites present in these samples characterized temperature-programmed desorption/thermogravimetric analysis (TPD-TGA) measurements 2-propanol 2-propanamine. Weight changes showed that the grew at rate 8.8 × 1017 W atoms/m2 per cycle. Scanning transmission electron microscopy/energy-dispersive spectroscopy...

Nanolaminates composed of thin alternating layers Al2O3 and TiO2 (ATO) were engineered by using atomic layer deposition as the dielectric material for a Pt-on-carbon catalytic condenser. Investigation assessed synthesis parameters including temperature, thicknesses, total number layers, capping on maximum charge accumulation in Pt catalyst. The highest capacitance ATO configuration demonstrated specific ∼1200 nF/cm2 with working voltages ±5 V, enabling storage 4 × 1013 electrons or holes per...

ZrO2 powders were modified by atomic layer deposition (ALD) with CeO2 and ZrO2, using Ce(TMHD)4 Zr(TMHD)4 as the precursors, in order to determine effect of ALD films on structure, surface area, catalytic properties ZrO2. Growth rates measured gravimetrically found be 0.017 nm/cycle for 0.031 The addition 20 cycles either or was stabilize area powder following calcination 1073 K suppress tetragonal-to-monoclinic transition. Shrinkage wafers also suppressed films. When used a support Pd CO...

Catalytic condensers stabilize charge on either side of a high-k dielectric film to modulate the electronic states catalytic layer for control surface reactions. Here, carbon sputtering provided fast, large-scale fabrication metal-carbon required industrial application. Carbon films were sputtered HfO2 dielectric/p-type Si with different thickness (1, 3, 6, 10 nm), and enhancement conductance capacitance was observed upon increasing following thermal treatment at 400 °C. After Pt deposition...

For programmable catalysis applications, nanolaminates composed of thin alternating layers alumina and titania (ATO) were engineered using atomic layer deposition (ALD) as the dielectric material for a Pt-on-carbon catalytic condenser. Systematic investigation assessed synthesis parameters such temperature, thicknesses, total number (and interfaces), presence capping on maximum achievable charge accumulation in Pt catalyst layer. The highest capacitance ATO configuration demonstrated...

Selective hydrogenation of lignin-derived alkyl-phenol to alkyl-cyclohexanone is a key step in the synthesis renewable caprolactone from monomers. p-cresol, model compound for monomers, 4-methyl-cyclohexanone was conducted using Pd/γ-Al2O3 continuous three-phase flow reactor, with side products 4-methyl cyclohexanol. High conversion (85%) and selectivity (>93%) demonstrated at ambient reaction pressure. Evaluation different parameters showed that determined by surface coverage p-cresol...

The properties of 20 wt % CeO2 and 21 Ce0.5Zr0.5O2 films, deposited onto a γ-Al2O3 by Atomic Layer Deposition (ALD), were compared to bulk γ-Al2O3-supported samples on which or CeO2–ZrO2 impregnation. Following calcination 1073 K, the ALD-prepared catalysts showed much lower XRD peak intensities, implying that these existed as thin rather than larger crystallites. addition 1 Pd each supports, exhibited higher rates for CO oxidation due better interfacial contact between ceria-containing...

Accelerating catalytic chemistry and tuning surface reactions requires precise control of the electron density metal atoms. In this work, nanoclusters platinum were supported on a graphene sheet within condenser device that facilitated or hole accumulation in active sites with negative positive applied potential, respectively. The was fabricated by depositing top p-type Si wafer an amorphous HfO2 dielectric (70 nm), which placed layer 2-4 nm graphene. Potential +/-6V to Pt/graphene relative...

Catalytic condensers comprised of ion gels separating a metal electrode from platinum-on-carbon active layer were fabricated and characterized to achieve more powerful, high surface area dynamic heterogeneous catalyst surfaces. Ion PVDF/ [EMIM]+[TFSI]- spin coated as 3.8 μm film on Au surface, after which carbon sputtering 1.8 nm electron-beam evaporation 2 Pt clusters created an exposed reactant gases. Electronic characterization indicated that most charge condensed within the nanoclusters...

Ray Gorte has made major contributions to catalysis science and engineering in several fields throughout his more than 40 years career spanning surface science, solid acids, fuel cells electrolyzers, encapsulated catalysts, biomass conversion, atomic layer deposition catalysts. The desire for practical advances achieved using fundamental principles been the focus of Ray's distinguished that led important discoveries all areas he worked in. direct sincere feedback provided students,...

Selective hydrogenation of lignin-derived alkyl-phenol to alkyl-cyclohexanone is a key step in the synthesis renewable caprolactone from monomers. p-cresol, model compound for monomers, 4-methyl-cyclohexanone was conducted using Pd/γ-Al2O3 continuous three-phase flow reactor with side products 4-methyl cyclohexanol. High conversion (85%) and selectivity (>93%) were demonstrated at ambient reaction pressure. Evaluation different parameters showed that determined by surface coverage p-cresol...