Vectorial electron transfer for improved hydrogen evolution by mercaptopropionic-acid-regulated CdSe...

Area of Science:

• Materials Science
• Photochemistry
• Catalysis

Background:

• Artificial photosynthesis aims to mimic natural processes for sustainable energy production.
• Developing efficient photocatalytic systems for hydrogen evolution is crucial for clean energy.
• Quantum dots (QDs) offer unique light-harvesting properties for photocatalysis.

Purpose of the Study:

• To construct a visible-light-driven hydrogen evolution system using a CdSe QDs-TiO2-Ni(OH)2 ternary assembly.
• To investigate the roles of each component in the photocatalytic process.
• To achieve high hydrogen evolution rates and turnover frequencies.

Main Methods:

• Fabrication of a ternary assembly using CdSe quantum dots, TiO2, and Ni(OH)2 with mercaptopropionic acid linker.
• Visible-light irradiation in a basic aqueous solution (pH 11.0).
• Characterization using X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and inductively coupled plasma optical emission spectroscopy.

Main Results:

• The CdSe QDs-TiO2-Ni(OH)2 assembly achieved a hydrogen evolution rate of 10.1 mmol g⁻¹ h⁻¹.
• A high turnover frequency of 5140 h⁻¹ with respect to CdSe QDs was observed.
• Ni(OH)2 demonstrated efficient catalytic activity, while TiO2 acted as an electron mediator facilitating vectorial electron transfer.

Conclusions:

• The constructed ternary assembly effectively utilizes visible light for hydrogen evolution.
• The system mimics natural photosynthesis by integrating light harvesting, electron mediation, and catalysis.
• This work represents a significant advancement towards developing efficient artificial photosynthesis systems.