Enhanced charge transfer via NH2-MIL-125@ NH2/H-MIL-125 hetero-frameworks for photocatalytic H2 evolution

Abstract

The efficient transfer of photogenerated carriers is essential to the photocatalytic H2 evolution. Herein, we designed and synthesized a kind of novel NH2-MIL-125@NH2/H-MIL-125 hetero-frameworks with nanopore structure to drive efficient charge transfer for photocatalytic H2 evolution. Single-ligand NH2-MIL-125 (NM) and dual-ligand NH2/H-MIL-125 (NHM), which have similar composition, structure and well-matched energy band, were selected as the core and shell to prepare the NM@NHM hetero-framework as a proof-of-principle system. The hetero-framework strategy is proposed to intensify the charge transfer and thus enhance the photocatalytic activity. The H2 evolution rate of optimal NM@NHM hetero-framework can reach 2.25 mmol g−1 h−1 under visible light, much higher than pristine NM (0.726 mmol g−1 h−1) and NHM (1.27 mmol g−1 h−1). Such high performance can be attributed to the hetero-framework structure consisting of NM and NHM with similar composition and structure, which reduces the interfacial resistance in the charge transfer, thus facilitating the photocatalytic H2 evolution. Our work may provide a new strategy for the rational design of high-performance photocatalysts.