Pyrogallol[4]arene Coordination Nanocapsule Micelle as Bioinspired Water Reduction Catalyst

Herein, we describe the hydrothermal synthesis of a novel cobalt-seamed C-ethylpyrogallol­[4]­arene-based metal–organic nanocapsule (Co24PgC2 MONC) that can be easily converted into micelles in water using Tween-20, a natural polysorbitan. Such micellar forms exhibit increased efficiency up to 16-fold for photocatalytic hydrogen evolution with a high rate of 7.2 mmol g–1 h–1 outperforming Co24PgC2 MONC without Tween-20. Notably, Tween-20 is critical in this system because it can homogenize the heterogeneous Co24PgC2 MONC catalyst, provide numerous accessible active sites and inhibit the energy transfer between photosensitizer and nanocapsules. This investigation not only provides a new approach to study a water-insoluble coordination complex but also offers an effective strategy to increase their hydrogen evolution catalytic activities.