Department of Applied Chemistry and Biochemistry, Graduate School of Science and Technology, Kumamoto University, Kumamoto, 860-8555, Japan.
Unit of Elements Strategy Initiative for Catalysts &Batteries, Kyoto University, Kyoto, 615-8245, Japan.
Sci Rep. 2016 Jul 8;6:29737. doi: 10.1038/srep29737.
Pulsed arc-plasma (AP) deposition of an Rh overlayer on an Fe-Cr-Al stainless steel foil produced a composite material that exhibited high activity for automotive three-way catalysis (TWC). The AP pulses deposited metallic Rh nanoparticles 1-3 nm in size, whose density on the surface increased with the number of pulses. This led to coalescence and grain growth on the foil surface and the eventual formation of a uniform two-dimensional Rh overlayer. Full coverage of the 51 μm-thick flat foil by a 3.2 nm-thick Rh overlayer was achieved after 1,000 pulses. A simulated TWC reaction using a miniature honeycomb fabricated using flat and corrugated foils with the Rh overlayers exhibited successful light-off at a practical gaseous hourly space velocity of 1.2 × 10(5) h(-1). The turnover frequency for the NO-CO reaction over the metallic honeycomb catalyst was ca. 80-fold greater than that achieved with a reference Rh/ZrO2-coated cordierite honeycomb prepared using a conventional wet impregnation and slurry coating procedure. Despite the nonporosity and low surface area of the foil-supported Rh overlayer compared with conventional powder catalysts (Rh/ZrO2), it is a promising alternative design for more efficient automotive catalysts that use less Rh loading.
脉冲电弧等离子体（AP）在 Fe-Cr-Al 不锈钢箔上沉积 Rh 覆盖层，制备出一种复合材料，该复合材料在汽车三效催化转化器（TWC）中表现出高活性。AP 脉冲沉积的金属 Rh 纳米颗粒尺寸为 1-3nm，其表面密度随脉冲数的增加而增加。这导致箔表面的团聚和晶粒生长，并最终形成均匀的二维 Rh 覆盖层。经过 1000 个脉冲，厚度为 51μm 的扁平箔完全覆盖了 3.2nm 厚的 Rh 覆盖层。使用带有 Rh 覆盖层的扁平箔和波纹箔制造的微型蜂窝体进行模拟 TWC 反应，在实际的气体空速为 1.2×10(5)h(-1)时成功实现了起燃。金属蜂窝体催化剂上的 NO-CO 反应的转换频率比使用传统湿浸渍和浆料涂覆工艺制备的参考 Rh/ZrO2 涂覆堇青石蜂窝体的催化剂高约 80 倍。尽管与传统粉末催化剂（Rh/ZrO2）相比，箔支撑 Rh 覆盖层的非多孔性和低表面积，但它是一种更有效的汽车催化剂的有前途的替代设计，使用更少的 Rh 负载。
