Translational and rotational motion of solid matter is normally driven by external physical forces. Here we report that under oxygen atmosphere inside an environmental transmission electron microscope, catalytic palladium nanoparticles underwent a self-propelled, peristalsis-like locomotion on a supporting substrate at a relatively low temperature. Surprisingly, the particles maintained crystalline interior and even conserved their initial crystal orientations during the dramatic liquid-like motion. Such “peristaltic” crystal migration with shape oscillation is found to be mediated by profuse surface diffusion, under chemical driving forces from palladium-catalyzed gaseous oxidation of a carbonaceous layer. These findings open a new avenue of efficient heterogeneous catalysis, and reveal emergent behavior that can arise out of an energy-metabolizing nano-system.

固体物质的平移和旋转运动通常由外部物理力驱动。在这里我们报告说，在环境透射电子显微镜内的氧气气氛下，催化钯纳米粒子在相对较低的温度下在支撑基板上经历了自推进的、蠕动状运动。令人惊讶的是，这些粒子在剧烈的液体状运动过程中保持了晶体内部，甚至保持了它们的初始晶体取向。在钯催化的碳质层气态氧化的化学驱动力下，发现这种具有形状振荡的“蠕动”晶体迁移是由大量表面扩散介导的。这些发现开辟了高效多相催化的新途径，