Double Confinement Hydrogel Network Enables Continuously Regenerative Solar-to-Hydrogen Conversion.

Soft matter catalyst system allowing controllable manipulation of the organized nanostructure and surface property holds the potential for renewable energy. Here we demonstrate the construction of a continuously regenerative hydrogel photocatalyst that confines the metal-thiolate coordination induced nanocavity into robust micro-sized spongy network for water splitting. Thanks to low vaporization enthalpy and fast proton mobility of water molecules confining in nanocavities, the composite delivers outstanding photocatalytic H 2 production (TOF of 4568 H 2  h -1 ), nearly 4.5 times higher than that on the catalyst without confinements. Incorporating with conductive polymers, the TOF is substantially improved to 7819 H 2  h -1 . Impressively, continuous regeneration is for the first time achieved with H 2 production retention improved from 24 % to 72 % by regulating optically-active catalyst surfaces. This optical regeneration method provides new avenues for sustainable solar energy conversion.