A5085965254- Catalytic Processes in Materials Science
- Catalysis and Oxidation Reactions
- Catalysts for Methane Reforming
- Catalysis and Hydrodesulfurization Studies
- Electrocatalysts for Energy Conversion
- Catalysis for Biomass Conversion
- Mesoporous Materials and Catalysis
- Ammonia Synthesis and Nitrogen Reduction
- Electron and X-Ray Spectroscopy Techniques
- Advanced Chemical Physics Studies
- Metal-Organic Frameworks: Synthesis and Applications
- Advanced Electron Microscopy Techniques and Applications
- Ion-surface interactions and analysis
- Zeolite Catalysis and Synthesis
- Nanomaterials for catalytic reactions
- Spectroscopy and Quantum Chemical Studies
- Transition Metal Oxide Nanomaterials
- Industrial Gas Emission Control
- Hydrogen Storage and Materials
- Copper-based nanomaterials and applications
- Advanced Photocatalysis Techniques
- Dendrimers and Hyperbranched Polymers
- CO2 Reduction Techniques and Catalysts
- Gas Sensing Nanomaterials and Sensors
Lawrence Berkeley National Laboratory
2013-2018
Berkeley College
2017-2018
University of California, Berkeley
2013-2017
Material Sciences (United States)
2016
Université Libre de Bruxelles
2008-2014
The interaction of the metal and support in oxide-supported transition-metal catalysts has been proven to have extremely favorable effects on catalytic performance. Herein, mesoporous Co3O4, NiO, MnO2, Fe2O3, CeO2 were synthesized utilized CO oxidation reactions compare activities before after loading 2.5 nm Pt nanoparticles. Turnover frequencies (TOFs) pure oxides 0.0002–0.015 s–1, while silica was catalytically inactive oxidation. When nanoparticles loaded onto oxides, TOFs Pt/metal oxide...
Hydrogenations of CO or CO2 are important catalytic reactions as they interesting alternatives to produce fine chemical feedstock hence avoiding the use fossil sources. Using monodisperse nanoparticle (NP) catalysts, we have studied CO/H2 (i.e., Fischer-Tropsch synthesis) and CO2/H2 reactions. Exploiting synchrotron based in situ characterization techniques such XANES XPS, were able demonstrate that 10 nm Co NPs cannot be reduced at 250 °C while supported on TiO2 SiO2 complete reduction...
Carbon dioxide capture and use as a carbon feedstock presents both environmental industrial benefits. Here we report the discovery of hybrid oxide catalyst comprising manganese nanoparticles supported on mesoporous spinel cobalt oxide, which catalyses conversion to methanol at high yields. In addition, carbon–carbon bond formation is observed through production ethylene. We document existence an active interface between surface layers by using X-ray absorption spectroscopy electron...
Here, we report the Pt nanoparticle mediated reduction (oxidation) and lattice expansion (contraction) of mesoporous CeO2 under H2 (O2) atmospheres in temperature range 50–350 °C. We found that Pt/CeO2 catalyst was partially reduced (and fully oxidized back O2) as demonstrated by several situ techniques: APXPS spectra (4d core levels) for topmost surface, NEXAFS total electron yield (at M5,4 edges) near surface regions, (N)EXAFS fluorescence L3 edge) bulk. Moreover, XRD EXAFS showed...
Pt, Rh, and Pd nanoclusters stabilized by PAMAM dendrimer are used for the first time in a gas flow reactor at high temperature (150–250 °C). Pt show very activity hydrogenation of methylcyclopentane (MCP) 200–225 °C with turnover freqency (TOF) up to 334 h–1 selectivity 99.6% ring opening isomerization conversion (94%). Rh different reaction, that is, 175 cracking higher whereas perform enlargement plus dehydrogenation, while maintaining activity. The difference these results as compared...
The hydrogenation of crotonaldehyde by platinum nanoparticles supported on cobalt oxide was used as a reaction to probe the effect interface between two materials activity and selectivity catalyst. Four potential products can be formed this reaction: propylene, butyraldehyde, crotyl alcohol, butanol. When Pt are SiO2, an inert support, only propylene butyraldehyde formed. However, when is oxide, alcohols make up roughly 40% total activity, indicating that plays pivotal role in reaction, much...
The Fischer-Tropsch process, or the catalytic hydrogenation of carbon monoxide (CO), produces long chain hydrocarbons and offers an alternative to use crude oil for chemical feedstocks. observed size dependence cobalt (Co) catalysts reaction was studied with colloidally prepared Co nanoparticles a transient kinetics reactor capable measurements under non-steady-state conditions. 4.3 nm 9.5 diameters were synthesized tested atmospheric pressure conditions H2 /CO=2. Large differences in...
In this paper, we report the colloidal synthesis and detailed characterization of 11 nm bimetallic CoCu nanoparticle catalysts. Presently Co Cu is an attractive combination because their respective properties for industrially important Fischer–Tropsch methanol reactions CO (and CO2) with H2. We preparation catalysts by deposition metal nanoparticles, both within mesoporous silica (MCF-17) on native oxide surface a silicon wafer. Subsequent phase separation into phase-segregated (i.e., dimer)...
Abstract The present review discusses the current state of art microscopic and spectroscopic characterization techniques available to study surfaces interfaces under working conditions. Microscopic such as environmental transmission electron microscopy in situ are first discussed showing their applications field nanomaterials catalysis. Next sum frequency generation vibrational spectroscopy is discussed, giving probing examples surface studies gaseous Synchrotron based X‐ray also examined...
The appropriate combination of titania and silica, sulfating non-sulfating support, respectively, results in Pd catalysts with improved water sulfur tolerance methane combustion. For the first time catalyst recovers initial activity after one cycle under lean-burn conditions without additional regenerating treatments.
The surface structure of Pt(557) during the catalytic oxidation hydrogen was studied with in situ scanning tunneling microscopy and X-ray photoelectron spectroscopy. At 298 K, Pt oxide formed after exposing to approximately 1 Torr O2 can be readily removed by H2, at H2 partial pressures below 50 mTorr. Water is detected as product gas phase, which also coadsorbs hydroxyl groups on surface.
We characterize the surface chemical states of reactants and catalysts under reaction conditions to elucidate composition effect platinum–iron bimetallic nanoparticles on catalytic hydrogenation organic molecules. The ethylene is drastically accelerated 2 nm PtFe as compared pure Pt. Sum frequency generation (SFG) vibrational spectroscopy indicates that incorporation Fe into Pt nanoparticle weakens adsorption ethylidyne, an inactive spectator species, catalyst surface. Similarly, turnover...
Post-synthetic aluminum grafting is employed to synthesize highly selective hydroisomerization catalyst and demonstrate the effect of acid strength density, microstructure, platinum nanoparticle size on reaction rate selectivity.
The catalytic hydrogenation of carbon monoxide, known as the Fischer–Tropsch process, is a technologically important, complex multipath reaction which produces long-chain hydrocarbons. In order to access initial kinetics and mechanism, we developed reactor that provides information under nonsteady state conditions. We tested CoMgO catalyst monitored product formation within 2 s exposure CO well time dependence high molecular weight products (in 60 window) found drastic changes in...