In-Situ Self-Transformation Growth of Binary g-C3N4/CdS Heterojunctions for Efficient Hydrogen Evolution and Wastewater Treatment

Developing uniformly dispersed heterojunction photocatalysts with highly coupled interfaces is critical for increasing the photocatalytic efficiency of semiconductor photocatalysts. We used an in-situ self-transformation technique to create an efficient heterojunction photocatalyst from g-C₃N₄ and CdS. Melamine-CdS composites were used as a precursor in this synthesis. The microscopic observations revealed that CdS nanoparticles were distributed uniformly on the g-C₃N₄ base. FTIR and XRD spectra ascertained that g-C₃N₄ and CdS cohabit in the photocatalyst samples. The synthesized binary photocatalysts were used for hydrogen evolution and the degradation of synthetic dyes from wastewater under simulated sunlight irradiation. Rhodamine B and Methyl orange in solution were decomposed under induced visible light exposure. The g-C₃N₄/CdS showed catalytic dye removal efficiency of 74.03% and 84.03% against methyl orange and Rhodamine B, respectively. During water splitting experiments, g-C₃N₄/CdS heterojunction showed a reasonable H₂ production rate of 2910 µmolh⁻¹ g⁻¹ after five hours of light exposure. The catalytic activity, rate constant, and stability of the composite photocatalyst were significantly higher than pure g-C₃N₄ and CdS.