Metal-free Hydrogen Generation from Seawater and Silicon Waste: A Circular Approach

Area of Science:

• Catalysis
• Green Chemistry
• Materials Science

Background:

• Hydrogen is vital for energy transition and decarbonization.
• Silane hydrolysis is an under-explored route for hydrogen generation.
• Existing methods often rely on expensive noble-metal catalysts.

Purpose of the Study:

• To develop a highly active, transition metal-free method for hydrogen production from seawater and hydrosilanes.
• To investigate the use of simple bases and promoting solvents for efficient catalysis.
• To demonstrate the circularity of the process by recycling solvents and reusing by-products.

Main Methods:

• Utilized simple bases as catalysts and dimethyl sulfoxide as a promoting solvent for silane hydrolysis.
• Employed mechanistic and computational studies to understand the reaction pathway.
• Applied the method to phenylsilane and polymethylhydrosiloxane (PMHS) using seawater.

Main Results:

• Achieved a high turnover frequency (TOF) of 202 ± 5 min-1 for phenylsilane hydrolysis, surpassing existing metal-free and noble-metal systems.
• Generated hydrogen from seawater using PMHS waste at rates up to 70.2 molH2/gcat/h.
• Demonstrated successful solvent recyclability and efficient depolymerization of polysiloxane by-products into valuable chlorosilane monomers.

Conclusions:

• The developed transition metal-free method offers a highly efficient and sustainable route for hydrogen production.
• The process exhibits excellent catalytic activity, solvent recyclability, and waste valorization, promoting a circular economy.
• This approach provides a promising alternative for clean hydrogen generation and sustainable chemical manufacturing.