Efficient Z-scheme LaCoO3/In2O3 heterostructure photocatalyst for fast dye degradation under visible light irradiation

摘要

Lanthanum cobaltite (LaCoO3) is an active catalyst for photocatalytic application owing to its good structural stability, visible light absorbance ability, low cost and earth abundant. Significant research works have been carried out to accelerate the photocatalytic activity of LaCoO3. Particularly, controlling the band potentials, charge carrier transfer and electron-hole separation play a critical role in photodegradation process. By considering all these facts, in the present research work, LaCoO3/In2O3 heterostructure photocatalyst is synthesized via facile wet chemical route and its photodegradation activity is studied for the first time. The structural analysis confirmed the formation of cubic In2O3 phase along with rhombohedral LaCoO3 heterostructure. Moreover, X-ray photoelectron spectroscopy (XPS) analysis revealed the corresponding binding energy state of LaCoO3/In2O3 sample. The binding energy of In3d peak position in XPS and the lattice spacing of (222) plane in HR-TEM infer the In2O3 phase evolution with LaCoO3. Eventually, methylene blue (MB) dye has been utilized for investigating dye degradation ability of bare LaCoO3 and LaCoO3/In2O3 heterostructure photocatalysts for various concentrations of In2O3. Among them, 4 mol. In-doped LaCoO3/In2O3 heterostructure photocatalyst exhibits an efficient dye degradation rate and time (similar to 98 in 20 min) under visible light irradiation. The photodegradation repeatability experiment showed the stable degradation activities even up to 10 cycles. Also, the interaction of MB dye molecules with LaCoO3/In2O3 photocatalyst has been studied theoretically. This result ensured that a desired band edge alignment between LaCoO3 and In2O3 phases is a reason for efficient photocatalytic reaction. It also revealed the developing heterostructure formation using suitable metal oxide with LaCoO3 semiconductor to be an outstanding one, especially for attaining an efficient dye degradation rate and time. Thus, this study notifies us that there will be a hope certainly cultivated in the photocatalytic research realm.