Issue 20, 2024

Catalytic NH3 oxidation affected by the nanometric roughness of the platinum overlayer

Abstract

Pulsed cathodic arc–plasma deposition was employed to create a few nanometre-thick Pt overlayer on a 50 μm-thick Fe–Cr–Al metal (SUS) foil, resulting in an effective NH3 oxidation catalyst fabrication. This catalyst exhibited a turnover frequency (TOF) exceeding 100 times that of Pt nanoparticles. In this study, Pt overlayer catalysts with varying degrees of surface roughness were fabricated using different metal foil substrates: mirror-polished (Pt/p-SUS), unpolished (Pt/SUS) and roughened by the formation of a surface oxide layer (Pt/Al2O3/SUS). The nanoscale roughness was comprehensively analysed using electron microscopy, laser scanning confocal microscopy and chemisorption techniques. NH3 oxidation activity, measured at 200 °C, followed an increasing trend in the order of Pt/Al2O3/SUS < Pt/SUS < Pt/p-SUS, despite a decrease in the apparent Pt surface area in the same order. Consequently, the calculated TOF was markedly higher for Pt/p-SUS (267 min−1) compared to Pt/SUS (107 min−1) and Pt/Al2O3/SUS (≤22 min−1). The smooth Pt overlayer surface also favoured N2 yield over N2O at this temperature. This discovery enhances our fundamental understanding of high-TOF NH3 oxidation over Pt overlayer catalysts, which holds significance for the advancement and industrial implementation of selective NH3 oxidation processes.

Graphical abstract: Catalytic NH3 oxidation affected by the nanometric roughness of the platinum overlayer

Supplementary files

Article information

Article type
Paper
Submitted
17 مارٕچ 2024
Accepted
28 اپریل 2024
First published
29 اپریل 2024

Nanoscale, 2024,16, 9781-9790

Catalytic NH3 oxidation affected by the nanometric roughness of the platinum overlayer

M. Machida, N. Yamasaki, T. Miyoshi, H. Kusaba, T. Sato, K. Awaya, H. Yoshida, J. Ohyama, T. Ohori, K. Oka, K. Fujii and N. Ishikawa, Nanoscale, 2024, 16, 9781 DOI: 10.1039/D4NR01156B

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