哈尔滨工业大学王威团队报道了H2O2的不对称分解不足以推动催化微电机。相关研究成果发表在2021年8月2日出版的《美国化学会杂志》。

利用不对称化学反应，如过氧化氢的催化分解，是设计化学微机械的一个普遍原则。

与直觉相反，研究人员以半涂有铂（Pt）或过氧化氢酶的Janus微电机为例，说明这种反应不足以驱动微电机实现自我推进。特别是，通过在SiO2微球上退火一层铂薄膜，得到的半装饰有离散铂纳米颗粒的微球在H2O2中的游动速度比未退火的微球慢约80%，即使它们都能催化产生相当数量的氧气。同样，尽管对分解H2O2具有高催化活性，但用过氧化氢酶半功能化的SiO2微球显示出可忽略的自推进能力。

除了强调催化盖的表面形态如何启用/禁用化学微电机，该研究为理解化学是如何驱动纳米和微观物体（或不是）提供了一个全新的视角：该结果与强调H2O2在非电化学途径上的电化学分解的自电泳机制一致。更广泛地说，该发现是理解和设计纳米和微机械、开发有效的活性胶体模型系统以及将酶与活性物质联系起来的一个关键部分。

附：英文原文

Title: Active, Yet Little Mobility: Asymmetric Decomposition of H2O2 Is Not Sufficient in Propelling Catalytic Micromotors

Author: Xianglong Lyu, Xiaoxia Liu, Chao Zhou, Shifang Duan, Pengzhao Xu, Jia Dai, Xiaowen Chen, Yixin Peng, Donghao Cui, Jinyao Tang, Xing Ma, Wei Wang

Issue&Volume: August 2, 2021

Abstract: A popular principle in designing chemical micromachines is to take advantage of asymmetric chemical reactions such as the catalytic decomposition of H2O2. Contrary to intuition, we use Janus micromotors half-coated with platinum (Pt) or catalase as an example to show that this ingredient is not sufficient in powering a micromotor into self-propulsion. In particular, by annealing a thin Pt film on a SiO2 microsphere, the resulting microsphere half-decorated with discrete Pt nanoparticles swims ～80% more slowly than its unannealed counterpart in H2O2, even though they both catalytically produce comparable amounts of oxygen. Similarly, SiO2 microspheres half-functionalized with the enzyme catalase show negligible self-propulsion despite high catalytic activity toward decomposing H2O2. In addition to highlighting how surface morphology of a catalytic cap enables/disables a chemical micromotor, this study offers a refreshed perspective in understanding how chemistry powers nano- and microscopic objects (or not): our results are consistent with a self-electrophoresis mechanism that emphasizes the electrochemical decomposition of H2O2 over nonelectrochemical pathways. More broadly, our finding is a critical piece of the puzzle in understanding and designing nano- and micromachines, in developing capable model systems of active colloids, and in relating enzymes to active matter.

DOI: 10.1021/jacs.1c04501

Source: https://pubs.acs.org/doi/10.1021/jacs.1c04501