Characterizing Carbon Ring‑C3N4 Nanosheets as a Light-Harvesting and Charge Carrier Transfer Agent: Photodegradation of Methylene Blue and Photoconversion of CO2 to CH4 as Case Studies
journal contributionposted on 05.03.2021, 22:43 by Hossein Ashrafi, Morteza Akhond, Maryam Zare, Ghodratollah Absalan
Carbon ring–carbon nitride nanosheets (Cring-C3N4) were synthesized by using glucose as the carbon source. The Cring-C3N4 was characterized in order to check its ability in harvesting light in the visible region and transferring the charge carriers. Degradation of methylene blue (MB) after being adsorbed on the surface of the photocatalyst and also the photoreduction of CO2 to CH4 were studied for proving applicability of Cring-C3N4 in solving pollution problem and fuel crisis. The results were compared with those of bulk C3N4. The results showed that the adsorption process was fit to the Langmuir model (with a Qmax of 130 mg/g) with a kinetic of the pseudo second order (with a Qe.cal of 180 mg/g). The photodegradation rate constant of MB proved that Cring-C3N4 nanosheets had a catalytic activity (0.0616/h) almost 26 times more than g-C3N4 in the presence of light. At a melamine/glucose mass ratio of 1000/50, the photoconversion rate of CO2 to CH4 (16.24 μmol/g·h) achieved nearly 24 times greater when compared to g-C3N4 and was comparable with the photodegradation rate of MB. In the presence of light, it was observed that the reduction of carbon dioxide to methane was via a process of eight electrons which predominated over the production of carbon monoxide with a process of two electrons. The Cring -C3N4 synergistically extended lifetime and photocarrier diffusion length. This photocatalyst can be effectively utilized in sustainable solar-to-fuel conversion processes as well as in environmental pollutant remediation.