Title
Sustainable production of value-added chemicals and fuels by using a citric acid-modified carbon nitride optical semiconductor
Author
Raquel Fernades
Year
2021
Journal
Applied Catalysis
Abstract
Citric acid-modified graphite-like carbon nitride materials (GCN-zCA) were synthetized by thermal co-polymerization of dicyandiamide with different amounts of citric acid (z = between 5 and 25 mg). The resulting materials presented surface porosity, defective polymeric structure, and enhanced visible light absorption in the 450−700 nm range, attributed to the existence of mid-gap states and n-π* electronic transitions. All the modified catalysts presented high selectivity (>99 %) towards the conversion of p-anisyl alcohol into p-anisaldehyde under visible-LED irradiation, the best performing photocatalyst (GCN-20CA) reaching 63 % yield (contrasting with 22 % obtained with bulk GCN) after 240 min reaction. GCN-20CA was also applied for hydrogen generation from water splitting. The modified material practically duplicated the hydrogen production when compared to bulk GCN (75 and 44 μmol H2 evolved in three hours, respectively), by using platinum nanoparticles as co-catalyst and EDTA as sacrificial electron donor. Moreover, p-anisyl alcohol was successfully used as sacrificial agent for water splitting, with simultaneous production of p-anisaldehyde and H2. Reusability tests showed that GCN-20CA remained stable in a series of consecutive runs both for p-anisaldehyde synthesis and hydrogen production.
Instrument
V-560, ISV-469, FT/IR-6800, FP-8300
Keywords
Citric acid, modified graphite, nanoparticles,