Rational optimization of g-C3N4/Co3O4 nanocomposite for enhanced photodegradation of Rhodamine B dye under visible light

Abstract

Heterogeneous catalysis is widely known as an efficient, clean, and low-cost technology to mitigate the environmental pollution of industrial effluents. This research aimed at optimizing the preparation and characterization of efficient g-C3N4/Co3O4 nanocomposite for catalytic removal of Rhodamine B (Rh B) dye. The detected XRD peaks for the prepared nano-Co3O4 are matched with the cubic crystal structure. In contrast, the broad peak at 27.3° corresponding to the graphite reflection of hkl (002) was noticeably weakened in the XRD pattern of the g-C3N4/Co3O4 composite. FTIR spectra of g-C3N4/Co3O4 nanocomposites revealed the active vibrational modes of each Co3O4 and g-C3N4 component. The microstructure study of g-C3N4 showed the strong interlayer stacking of carbon nitride nanosheets, while the surface morphology of g-C3N4/Co3O4 nanocomposite revealed a hybrid particulate system. EDS analysis indicated that the spot area of g-C3N4/Co3O4 confirmed the chemical ratios of carbon, nitrogen, cobalt, and oxygen. BET measurements of g-C3N4/Co3O4 showed a significant increase in the surface area and pore volume of single components due to the lamination of stacked g-C3N4 nanosheets by the intercalated Co3O4 nanoparticles. The prepared 30% g-C3N4/Co3O4 revealed the lowest value of Eg ~1.2 eV and the highest light absorptivity suggesting strong promotion for the photocatalytic performance under visible light. The maximum photocatalytic activity of about 87% was achieved by 30% g-C3N4/Co3O4 due to the photonic enhancement, which reduces the recombination of excited electrons. The developed nanocomposite with a g-C3N4/Co3O4 ratio of 0.3 exhibited high stability in its photocatalytic performance after four recycling times, and a slight decrease of about 7% was estimated after the 5th reuse test.