PDF(Pubmed)
Abstract：
Vesicle, a microscopic unit that encloses a volume with an ultrathin wall, is ubiquitous in biomaterials. However, it remains a huge challenge to create its inorganic metal-based artificial counterparts. Here, inspired by the formation of biological vesicles, we proposed a novel biomimetic strategy of curling the ultrathin nanosheets into nanovesicles, which was driven by the interfacial strain. Trapped by the interfacial strain between the initially formed substrate Rh layer and subsequently formed RhRu overlayer, the nanosheet begins to deform in order to release a certain amount of strain. Density functional theory (DFT) calculations reveal that the Ru atoms make the curling of nanosheets more favorable in thermodynamics applications. Owing to the unique vesicular structure, the RhRu nanovesicles/C displays excellent hydrogen oxidation reaction (HOR) activity and stability, which has been proven by both experiments and DFT calculations. Specifically, the HOR mass activity of RhRu nanovesicles/C are 7.52 A mg(Rh+Ru)-1 at an overpotential of 50 mV at the rotating disk electrode (RDE) level; this is 24.19 times that of commercial Pt/C (0.31 mA mgPt-1). Moreover, the hydroxide exchange membrane fuel cell (HEMFC) with RhRu nanovesicles/C displays a peak power density of 1.62 W cm-2 in the H2-O2 condition, much better than that of commercial Pt/C (1.18 W cm-2). This work creates a new biomimetic strategy to synthesize inorganic nanomaterials, paving a pathway for designing catalytic reactors.
摘要：
囊泡,用超薄壁包围体积的微观单元，在生物材料中无处不在。然而,创造无机金属基人造产品仍然是一个巨大的挑战。这里,受到生物囊泡形成的启发，我们提出了一种新颖的仿生策略，将超薄纳米片卷曲成纳米囊泡，这是由界面应变驱动的。受到最初形成的衬底Rh层和随后形成的RhRu覆盖层之间的界面应变的影响，纳米片开始变形以释放一定量的应变。密度泛函理论（DFT）计算表明，Ru原子使纳米片的卷曲在热力学应用中更有利。由于独特的囊泡结构，RhRu纳米囊泡/C表现出优异的氢氧化反应(HOR)活性和稳定性,实验和DFT计算都证明了这一点。具体来说,RhRu纳米囊泡/C的HOR质量活性为7.52Amg（RhRu）-1，在旋转圆盘电极（RDE）水平的过电位为50mV；这是商业Pt/C（0.31mAmgPt-1）的24.19倍。此外，具有RhRu纳米囊泡/C的氢氧化物交换膜燃料电池（HEMFC）在H2-O2条件下显示出1.62Wcm-2的峰值功率密度，比商业Pt/C（1.18Wcm-2）好得多。这项工作创造了一种新的仿生策略来合成无机纳米材料，为设计催化反应器铺平了道路。
