Comparative investigation of the characterization and photoactivity of gold-decorated graphitic carbon nitride: A study aspect of various synthesis approaches

Abstract

In recent decades, photocatalysis has been broadly considered one of the potential approaches for different environmental and medicinal applications. Different synthesis methods possess different benefits and drawbacks, requiring thorough comparison to optimize the usage of precursors, equipment, and photocatalysis activity of the materials. In this study, the gold-decorated graphitic carbon nitride nanocomposites (AuCN) were successfully fabricated via different methods, including hydrothermal (HT), radiation under visible light (Ir), and chemical reduction (VC). The characterization of the prepared materials was investigated, which showed an efficient exfoliation of graphitic carbon nitride (g-C3N4 − CN) sheets and uniform embedment of gold nanoparticles (AuNPs). The AuCN sample synthesized from the chemical approach (AuCN-VC) showed the strongest signals of the AuNPs content, while the material prepared from the hydrothermal method (AuCN-HT) indicated a better CN crystalline structure. Furthermore, the photoactivity of the fabricated materials was also compared with pristine CN via the analysis of band structure, elucidating an improvement in the band gap energy to 2.25, 2.59, and 2.68 eV for the hydrothermal, irradiation, and chemical approaches, respectively. According to the photocatalysis results, AuCN-VC possessed the highest photo behavior under visible illumination with the hydrogen peroxide yield production at 271.5 mM/g.h. Meanwhile, the observation in the antibacterial activity exhibited the greatest performance regarding AuCN-HT with the recorded inhibition zone diameters of 9.3 and 8.6 mm against P. aeruginosa and S. aureus, respectively, under photo-excitation. According to the aforementioned results, the synthesized AuCN composites suggest great potential in a wide range of applications in environmental remediation and renewable production.