Chinese Journal of Catalysis ›› 2021, Vol. 42 ›› Issue (8): 1345-1351.DOI: 10.1016/S1872-2067(20)63738-X

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Incorporating porphyrin-Pt in light-harvesting metal-organic frameworks for enhanced visible light-driven hydrogen production

Huihui Hu, Lingzhen Zeng, Zhe Li, Tianbao Zhu, Cheng Wang*()   

  1. State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China
  • Received:2020-08-28 Accepted:2020-11-18 Online:2021-08-18 Published:2020-12-10
  • Contact: Cheng Wang
  • About author:*. E-mail: wangchengxmu@xmu.edu.cn
  • Supported by:
    This work was supported by the Ministry of Science and Technology of China(2016YFA0200702);the National Natural Science Foundation of China(21671162);the National Natural Science Foundation of China(21721001)

Abstract:

Molecular catalysts for H2-evolution are of interest for their integration into light-harvesting complexes for photocatalytic water splitting. Here, we report the meso-tetra (4-carboxyphenyl) porphine [(TCPP)Pt II] complex as a molecular H2-evolving photocatalyst using chloranilic acid (CA) as a sacrificial electron donor, the choice of which is critical to the stability of the photocatalyst. When triethanolamine was used, [(TCPP)Pt II] decomposed to form Pt nanoparticles. Density functional theory calculations together with evidence from electrochemical and spectroscopic analyses suggested that the catalysis was possibly initiated by a proton-coupled electron transfer (PCET) to form [(TCPP)Pt I]-N-H, followed by another electron injection and protonation to form a [(TCPP)Pt II-hydride]-N-H intermediate that can release H2. As the whole catalytic cycle involves the injection of multiple electrons, a light-harvesting network should be helpful by providing multiple photo-induced electrons. Thus, we integrated this molecular catalyst into a light-harvesting metal-organic framework to boost its activity by ~830 times. This work presents a mechanistic study of the photocatalytic H2 evolution and energy transfer and highlights the importance of a light-harvesting network for multiple electron injections.

Key words: Artificial photosynthesis, Hydrogen evolution reaction, Light-harvesting, Metal-organic frameworks, Molecular catalyst