Carbon nitride quantum dots-modified cobalt phosphate for enhanced photocatalytic H₂ evolution

Area of Science:

• Materials Science
• Photocatalysis
• Green Chemistry

Background:

• Developing efficient photocatalysts for hydrogen production is crucial for sustainable energy.
• Cobalt phosphate (CoPi) is a promising material, but its photocatalytic efficiency needs improvement.
• Carbon nitride quantum dots (CNQDs) offer unique optoelectronic properties for enhancing photocatalysis.

Purpose of the Study:

• To synthesize and characterize novel carbon nitride quantum dots (CNQDs)-modified cobalt phosphate (CoPi) composites (CNQDs/CoPi-x).
• To evaluate the photocatalytic activity of these composites for hydrogen evolution under visible light.
• To investigate the role of CNQDs in improving the performance of CoPi-based photocatalysts.

Main Methods:

• Room temperature synthesis of CNQDs/CoPi-x composites.
• Characterization using FTIR, XRD, UV-Vis DRS, EIS, SEM, TEM/HR-TEM, XPS, and N2 adsorption.
• Photocatalytic hydrogen evolution experiments using Eosin Y as a sensitizer and triethanolamine as an electron donor under visible light.

Main Results:

• CNQDs modification did not significantly alter the morphology or surface area of CoPi.
• CNQDs/CoPi-x composites exhibited enhanced photocatalytic H2 evolution activity and stability compared to pure CoPi.
• CNQDs/CoPi-2 showed the highest hydrogen evolution rate (234.5 μmol h−1 g−1), 2.4 times greater than CoPi.

Conclusions:

• The enhanced performance of CNQDs/CoPi-2 is attributed to improved electron transfer facilitated by CNQDs and the visible-light activity of CNQDs.
• CNQDs act as effective co-catalysts, boosting the efficiency of CoPi for photocatalytic hydrogen production.
• This study presents a promising approach for developing efficient photocatalysts for solar-driven green hydrogen production.