Photocatalytic One-Pot Conversion of Aldehydes to Esters and Degradation of Rhodamine B Dye Using Mesoporous Graphitic Carbon Nitride

Abstract

Graphitic carbon nitride (g-C3N4) is a prominent semiconductor material for numerous photocatalytic applications. The mesoporous g-C3N4 (mpg-C3N4), a polymeric metal-free semiconductor proficient photocatalyst with triazine rings, is lightweight and has a high surface area. In this work, we elucidated the role of the mpg-C3N4 photocatalyst for the esterification of substituted benzaldehyde without any additives, a metal-free approach, and under visible light irradiation at room temperature. The mpg-C3N4 has been well characterized by various physicochemical techniques like X-ray diffraction, Fourier-transform infrared, UV–visible spectrophotometry, transmission electron microscopy (TEM), high-resolution TEM, elemental mapping, and the Brunauer–Emmett–Teller surface area. The catalyst characterization revealed that the as-prepared mpg-C3N4 material has a high surface area (97.39 m2/g), porosity, a medium band gap (2.83 eV), and a nanowire-like shape. The mpg-C3N4 properties enhanced the material’s photocatalytic activity toward the esterification of substituted benzaldehyde to afford a maximum of 35% conversion with 99% selectivity. A further extension of this work is explored for the organic dye degradation reaction, where it is observed that the materials are stable, sturdy, and reusable for more than eight cycles with a slight loss in activity. This research widens the versatile application of mpg-C3N4 with specific catalytic applications.

Carbon nitride based materials: more than just a support for single-atom catalysis

“…516,529,530 For the sake of practicality, easily available dyes, such as methyl orange (MO), methylene blue (MB) and rhodamine B (RhB), are employed in photodegradation studies as model molecules with UV-Vis spectroscopy monitoring. 531 As reported by Cui et al, pristine g-C 3 N 4 is capable of activating H 2 O 2 through visible light excitation, and driving the photogenerated oxy-radical reactive species to decompose RhB as a model reaction. 157 Among many modifications of CN-based materials, Ag single-atoms are one of the most chosen for pollutant degradation and water treatment.…”

Additive- and base-free tandem aerobic oxidative cleavage of olefins to esters using bifunctional mesoporous copper-incorporated Al-SBA-15

“…Esters are synthesized from tandem oxidative esterification of aldehydes or alcohols using transition metal catalysts, including calcium (Ca), vanadium (V), gold (Au), and palladium (Pd). [13][14][15][16][17][18] Among them, Au and Pd are commonly employed in oxidative esterification reactions, but the use of rare earth metals might limit large-scale industrial applications due to their scarcity. As an alternative, first-row transition metals (Co and Cu) supported on carbon and silica materials are reported for the oxidative esterification of alcohols or aldehydes.…”

Tuning of surface oxygen vacancies for enhancing photocatalytic performance under visible light irradiation in Sb2WO6 nanostructures

“…8,9 Over the past few years, various nitride-based, metal oxide, metal sulfide, and metal-organic frameworks (MOF)-based semiconductors have been reported for organic pollutant degradation. [10][11][12][13][14] However, because of the rapid recombination of charge carriers, large band gap, and low light absorption, these photocatalysts generally show sluggish activity. 15 Various strategies, including the formation of a nanocomposite and heterojunction and band gap engineering using defect-rich materials, are employed to improve photocatalytic activity.…”