Nanoconfinement-Induced Conversion of Water Chemical Adsorption Properties in Nanoporous Photocatalysts to Improve Photocatalytic Hydrogen Evolution

The diffusion and adsorption properties of water molecules on active sites play a pivotal role in the performance of heterogeneous photocatalytic reactions. Water inside the microporous carbon nanocage (MCN) can form an ideal system for boosting such nanoconfined water molecules' adsorption on the interior metal active sites compared with the bulk water system. The properties of water molecules adsorbed in the nanoconfined cavity and how they depend on the microporous pores and chemical functional groups of the carbon nanocage to promote water molecule adsorption on active sites have not been demonstrated before. Herein, we report a nano-constrained ZnIn2S4@C photocatalyst, maximizing water inside the MCN, and stabilization of its water molecules in the nanocavity can alter the localization electron distribution of water molecules at the ZnIn2S4 surface. This change demonstrates that the chemical adsorption capacity of the inside water on the photocatalyst can depend sensitively on the nanostructure, boosting the photocatalytic performance further. This work reveals an in-depth understanding of nano interior cavity effects on the water molecule adsorption process and provides a basis to understand how the nanoconfined space impacts the capability of water molecule chemical adsorption on the active sites of interior photocatalysts.