title: State of Supported Nickel Nanoparticles during Catalysis in Aqueous Media.
abstract: The state of Ni supported on HZSM-5 zeolite, silica, and sulfonated carbon was studied during aqueous-phase catalysis of phenol hydrodeoxygenation using in situ extended X-ray absorption fine structure spectroscopy. On sulfonated carbon and HZSM-5 supports, NiO and Ni(OH)2 were readily reduced to Ni(0) under reaction conditions (≈35 bar H2 in aqueous phenol solutions containing up to 0.5 wt. % phosphoric acid at 473 K). In contrast, Ni supported on SiO2 was not stable in a fully reduced Ni(0) state. Water enables the formation of Ni(II) phyllosilicate, which is more stable, that is, difficult to reduce, than either α-Ni(OH)2 or NiO. Leaching of Ni from the supports was not observed over a broad range of reaction conditions. Ni(0) particles on HZSM-5 were stable even in presence of 15 wt. % acetic acid at 473 K and 35 bar H2 .
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352 (USA).|School of Chemical and Biological Engineering, Washington State University, Pullman, WA 99364 (USA).
authors.forename: Zizwe A
authors.initials: ZA
authors.lastname: Chase
authors.affiliation: Department of Chemistry and Catalysis Research Institute, TU München, Lichtenbergstrasse 4, 85748 Garching (Germany).
authors.forename: Stanislav
authors.initials: S
authors.lastname: Kasakov
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352 (USA).
authors.forename: Hui
authors.initials: H
authors.lastname: Shi
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352 (USA).
authors.forename: Aleksei
authors.initials: A
authors.lastname: Vjunov
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352 (USA). john.fulton@pnnl.gov.
authors.forename: John L
authors.initials: JL
authors.lastname: Fulton
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352 (USA). donald.camaioni@pnnl.gov.
authors.forename: Donald M
authors.initials: DM
authors.lastname: Camaioni
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Building 401, 9700 S. Cass Avenue, Argonne, IL 60439 (USA).
authors.forename: Mahalingam
authors.initials: M
authors.lastname: Balasubramanian
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352 (USA).|School of Chemical and Biological Engineering, Washington State University, Pullman, WA 99364 (USA).|Current address: Shanghai Key Laboratory of Green Chemistry and Chemical Process, Department of Chemistry, East China Normal University, North Zhongshan Road 3663, 200062 Shanghai (P. R. China).
authors.forename: Chen
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352 (USA).|School of Chemical and Biological Engineering, Washington State University, Pullman, WA 99364 (USA).
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352 (USA). johannes.lercher@pnnl.gov.|Department of Chemistry and Catalysis Research Institute, TU München, Lichtenbergstrasse 4, 85748 Garching (Germany). johannes.lercher@pnnl.gov.
authors.forename: Johannes A
authors.initials: JA
authors.lastname: Lercher
keywords: EXAFS; XANES; hydrogenation; nanoparticles; nickel