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.

中文翻译：

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铂覆盖层纳米粗糙度对催化 NH3 氧化的影响

采用脉冲阴极电弧等离子体沉积在 50 μm 厚的 Fe-Cr-Al 金属 (SUS) 箔上创建几纳米厚的 Pt 覆盖层，从而形成有效的 NH ₃氧化催化剂。该催化剂的转换频率（TOF）超过 Pt 纳米颗粒的 100 倍。在本研究中，使用不同的金属箔基材制备了具有不同表面粗糙度的 Pt 覆盖层催化剂：镜面抛光 (Pt/p-SUS)、未抛光 (Pt/SUS) 和通过形成表面氧化物层进行粗糙化 (Pt /Al ₂ O ₃ /SUS)。利用电子显微镜、激光扫描共焦显微镜和化学吸附技术对纳米级粗糙度进行了综合分析。在 200 °C 下测量的NH _{3氧化活性遵循 Pt/Al 2} O ₃ /SUS < Pt/SUS < Pt/p-SUS顺序增加的趋势，尽管相同条件下 Pt 的表观表面积有所下降。命令。因此，与Pt/SUS (107 min ^-1 )和Pt/Al ₂ O ₃ /SUS (≤22 min ^-1 )相比， Pt/p-SUS (267 min ^-1 )的计算TOF明显更高。在此温度下，光滑的 Pt 覆盖层表面也比 N _{2 O 有利于 N 2}产率。这一发现增强了我们对Pt覆盖层催化剂高TOF NH _{3氧化的基本认识，对于选择性NH 3}氧化过程的进步和工业化实施具有重要意义。