It is known that when catalytic nanoparticles are functionalized with charged ligands, the polarity of these ligands can selectively control the approach of either (+) or (−) charged substrates, effectively rendering the particles’ catalytic activity charge-selective. In such experiments, however, the role of the counterions surrounding the charged ligands is generally not considered. The present work demonstrates that counterions—despite being only loosely bound—can have a dramatic effect on the on-particle catalysis. In particular, with the same charged ligands but with counterions of different sizes, catalysis can be allowed or completely blocked. Moreover, when counterions are exchanged, the same particles can be reversibly toggled between catalytically active and inactive states.

中文翻译：

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抗衡离子控制和切换纳米粒子上的电荷选择性催化

已知当催化纳米颗粒被带电荷的配体官能化时，这些配体的极性可以选择性地控制（+）或（-）带电荷的底物的接近，从而有效地使颗粒的催化活性具有电荷选择性。然而，在这样的实验中，通常不考虑围绕带电配体的抗衡离子的作用。目前的工作表明，尽管抗衡离子只是松散地结合在一起，但它对粒子上的催化作用却起着巨大的作用。特别地，使用相同的带电荷配体但具有不同大小的抗衡离子，可以允许或完全阻止催化作用。而且，当抗衡离子交换时，相同的粒子可以在催化活性和非活性状态之间可逆地转换。