Heikkinen N, Keskiväli L, Palo J, Reinikainen M, Putkonen M. Effect of Co-fed Water on a Co-Pt-Si/γ-Al
2O
3 Fischer-Tropsch Catalyst Modified with an Atomic Layer Deposited or Molecular Layer Deposition Overcoating.
ACS OMEGA 2022;
7:7725-7736. [PMID:
35284741 PMCID:
PMC8908501 DOI:
10.1021/acsomega.1c06512]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 02/11/2022] [Indexed: 06/14/2023]
Abstract
Atomic layer deposition (ALD) and molecular layer deposition (MLD) methods were used to prepare overcoatings on a cobalt-based Fischer-Tropsch catalyst. A Co-Pt-Si/γ-Al2O3 catalyst (21.4 wt % Co, 0.2 wt % Pt, and 1.6 wt % Si) prepared by incipient wetness impregnation was ALD overcoated with 30-40 cycles of trimethylaluminum (TMA) and water, followed by temperature treatment (420 °C) in an inert nitrogen atmosphere. MLD-overcoated samples with corresponding film thicknesses were prepared by using TMA and ethylene glycol, followed by temperature treatment (400 °C) in an oxidative synthetic air atmosphere. The ALD catalyst (40 deposition cycles) had a positive activity effect upon moderate water addition (P H2O/P H2 = 0.42), and compared with a non-overcoated catalyst, it showed resistance to irreversible deactivation after co-fed water conditions. In addition, MLD overcoatings had a positive effect on the catalyst activity upon moderate water addition. However, compared with a non-overcoated catalyst, only the 10-cycle MLD-overcoated catalyst retained increased activity throughout high added water conditions (P H2O/P H2 = 0.71). All catalyst variations exhibited irreversible deactivation under high added water conditions.
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