Synergistic CoX@g-C ₃ N ₄ (X = S, Se) Heterostructures for Enhanced Charge Transfer in Solar Hydrogen Production and Environmental Remediation

High Resolution Image Download MS PowerPoint Slide Heterostructure materials have gained importance as efficient semiconductor-based photocatalysts for hydrogen evolution by water splitting. We have successfully synthesized CoSe@g-C 3 N 4 and CoS@g-C 3 N 4 chalcogenide-based heterostructures and characterized them using PXRD, UV-DRS, Raman spectra, XPS, PL, FE-SEM, HR-TEM, BET, photocurrent, and LSV. The photocatalytic water splitting efficiency was measured in DI water using TEOA as a sacrificial reagent under visible light (λ ≥ 420 nm). The H 2 evolution rates in DI water for CoSe@g-C 3 N 4 and CoS@g-C 3 N 4 were 3222.34 and 2697.37 μmol g –1 h –1 with apparent quantum efficiencies (AQE) of 11.10% and 9.29%, respectively. Also, the degradation of methylene blue (MB) dye was examined here, and the efficiencies of CoSe@g-C 3 N 4 and CoS@g-C 3 N 4 were determined to be 96% and 93% under sunlight, respectively. The photocurrent densities of CoSe@g-C 3 N 4 and CoS@g-C 3 N 4 were 2.28 and 1.55 mA/cm 2, respectively. The CoSe@g-C 3 N 4 sample exhibited the highest H 2 evolution, MB dye degradation, and photocurrent rate due to the greater interfacial interactions between the CoSe nanoplate and porous g-C 3 N 4 nanosheet when compared to CoS@g-C 3 N 4 . Thus, it has the high capacity to separate photogenerated charges efficiently and transfer them from g-C 3 N 4 to CoSe active sites, which helped to enhance the photocatalytic activity. The Tafel slope values for CoSe@g-C 3 N 4 and CoS@g-C 3 N 4 were 51 and 66 mV dec –1, respectively. The lowest Tafel slope value of CoSe@g-C 3 N 4 exhibited a faster rate of reaction. Thus, the surface interaction between the CoSe and g-C 3 N 4 may create synergistic effects, which facilitate electron transport at the interface and significantly boost the catalytic activity. Therefore, CoSe@g-C 3 N 4 is a promising chalcogenide photocatalyst toward sustainable energy production and environmental remediation.