Building a Bridge from Papermaking to Solar Fuels

Area of Science:

• Materials Science
• Nanotechnology
• Green Chemistry

Background:

• Black liquor, a byproduct of papermaking, is typically burned for energy.
• Its potential as a feedstock for valuable materials remains largely untapped.
• Lignin-rich black liquor presents an opportunity for sustainable chemical synthesis.

Purpose of the Study:

• To investigate black liquor as a sustainable feedstock for synthesizing graphene quantum dots (GQDs).
• To explore the application of these GQDs in photocatalysis for solar fuel generation.
• To enhance the efficiency of TiO2 nanosheets using GQDs for water splitting and CO2 reduction.

Main Methods:

• Synthesis of GQDs from black liquor.
• Characterization of GQD properties, including up-conversion and photoluminescence.
• Fabrication of TiO2 nanosheet/GQD composites for photocatalytic studies.
• Testing solar-driven hydrogen and carbon monoxide production.

Main Results:

• Successfully synthesized GQDs from black liquor.
• Demonstrated that GQDs exhibit up-conversion and photoluminescence.
• GQDs effectively photosensitize TiO2 nanosheets and improve electron-hole separation.
• Achieved solar-powered generation of H2 from H2O and CO from H2O-CO2.

Conclusions:

• Black liquor is a viable and sustainable feedstock for producing functional graphene quantum dots.
• Graphene quantum dots can significantly enhance photocatalytic activity for solar fuel production.
• This approach offers a promising route for valorizing industrial waste and advancing renewable energy technologies.