Structural Evolution of Ni-Based Co-Catalysts on [Ca2Nb3O10]− Nanosheets during Heating and Their Photocatalytic Properties
1
Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straße 1, 40239 Düsseldorf, Germany
2
Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
3
Ludwig-Maximilians-Universität München, Butenandtstraße 5–13, 81377 München, Germany
4
Uppsala University, Lägerhyddsvägen 1, 75120 Uppsala, Sweden
*
Author to whom correspondence should be addressed.
Catalysts 2020, 10(1), 13; https://doi.org/10.3390/catal10010013
Received: 29 November 2019 / Revised: 16 December 2019 / Accepted: 18 December 2019 / Published: 20 December 2019
(This article belongs to the Special Issue Photocatalytic Nanocomposite Materials)
Nickel compounds are among the most frequently used co-catalysts for photocatalytic water splitting. By loading Ni(II) precursors, submonolayer Ni(OH)2 was uniformly distributed onto photocatalytic [Ca2Nb3O10]− nanosheets. Further heating of the nanocomposite was studied both ex situ in various gas environments and in situ under vacuum in the scanning transmission electron microscope. During heating in non-oxidative environments including H2, argon and vacuum, Ni nanoparticles form at ≥200 °C, and they undergo Ostwald ripening at ≥500 °C. High resolution imaging and electron energy loss spectroscopy revealed a NiO shell around the Ni core. Ni loading of up to 3 wt% was demonstrated to enhance the rates of photocatalytic hydrogen evolution. After heat treatment, a further increase in the reaction rate can be achieved thanks to the Ni core/NiO shell nanoparticles and their large separation.
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Keywords:
water splitting photocatalyst; niobate nanosheet; nanoparticle co-catalyst; in situ heating
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MDPI and ACS Style
Zhang, S.; Diehl, L.; Wrede, S.; Lotsch, B.V.; Scheu, C. Structural Evolution of Ni-Based Co-Catalysts on [Ca2Nb3O10]− Nanosheets during Heating and Their Photocatalytic Properties. Catalysts 2020, 10, 13.
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