Promoted Photocatalytic Hydrogen Evolution by Tuning the Electronic State of Copper Sites in Metal‐Organic Supramolecular Assemblies

• Published in: Angewandte Chemie International Edition Vol. 62; no. 47; pp. e202312306 - n/a
• Main Authors: Liu, Ning, Jiang, Jialong, Chen, Zhonghang, Wu, Boyuan, Zhang, Shiqi, Zhang, Yi‐Quan, Cheng, Peng, Shi, Wei
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 20.11.2023
• Edition: International ed. in English
• Subjects: Assemblies; Catalytic activity; Charge density; Coordination; Coordination Field Modulation; Copper; Discrete Complexes; Electron states; Electronic State; Hydrogen evolution; Hydrogen production; Metals; Modulation; Noble metals; Photocatalysis; Photocatalysts; Photocatalytic Hydrogen Evolution; Spin State
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202312306

The electronic state in terms of charge and spin of metal sites is fundamental to govern the catalytic activity of a photocatalyst. Herein, we show that modulation of the electronic states of Cu sites, without changing the coordination environments, of two metal‐organic supramolecular assemblies based on π⋅⋅⋅π stacking can significantly improve photocatalytic activity. The use of these heterogeneous photocatalysts, without using noble metal cocatalysts, resulted in an increase of the hydrogen production rate from 522 to 3620 μmol h−1 g−1. A systematical analysis revealed that the charge density and spin density of the metal centers are efficiently modulated via the modulation of the coordination fields around active copper (II) centers by the variation of the non‐coordination groups of terminal ligands, leading to the significant enhancement of photocatalytic activity. This work provides an insight into the electronic state of active metal centers for designing high‐performance photocatalysts. Two metal‐organic supramolecular assemblies based on π⋅⋅⋅π stacking were synthesized as heterogeneous noble‐metal‐free photocatalysts for hydrogen evolution. Without changing the coordination environments or the supramolecular structures, the spin and charge density of the Cu sites were tuned by modulating terminal ligands, resulting in an increased rate of photocatalytic hydrogen production.