Hybrid Carbon Nitride/Cobalt Phthalocyanine Nanocomposites for Efficient Photocatalytic Hydrogen Generation

The photocatalytic production of hydrogen stands out as a promising strategy to convert and store solar energy as chemical energy in the form of a sustainable energy carrier. In the present study, a hybrid photocatalyst based on cobalt phthalocyanine (CoPc) coupled with polymeric carbon nitride (CN) is synthesized using a simple, cost-effective, and upscalable method. Both components are held together in the hybrid nanocomposite via π-π interactions, as shown by detailed structural and optical characterization. The synergistic interaction between both components, CN, a metal-free semiconductor, valued for its stability and tunable electronic properties, and CoPc, known for its excellent light absorption and electronic properties, is evidenced in a proof-of-concept photocatalytic reaction: the photo-oxidation of benzyl alcohol (BzOH) to benzaldehyde (BzO). Chemical trapping reagents were employed to elucidate the reaction mechanism, showing favorable recombination dynamics of the hybrid photocatalyst (CoPc/CN) compared to the individual components. Furthermore, photocatalytic hydrogen production was conducted in an aqueous solution using triethanolamine (TEOA) as an electron donor, with the optimized CoPc/CN nanocomposite producing 1136.5 μmol h^-1 g_cat ^-1 of H₂, achieving a 50% higher hydrogen yield compared to pristine CN. These results contribute to the design of high-performance photocatalytic materials for promising solar-to-X transformations.