In the present study, the composite formation of carbon-doped ZnO (C–ZnO) with binary metal oxide semiconductor V
2
O
5
has been done to hinder the limitations of both ZnO and V
2
O
5
in the ...photocatalysis application. There are limited reports on heterostructure materials composed of ZnO and V
2
O
5
for visible-light-driven composite photocatalysts. But we have synthesized the nanocomposites with the crucial components of C–ZnO for the first time with V
2
O
5
, to the best of our knowledge. A C–ZnO/V
2
O
5
nanocomposite was synthesized from the different weight percents of V
2
O
5
concerning the C–ZnO nanoparticles. An XRD study depicted the orthorhombic phase of V
2
O
5
and the hexagonal wurtzite structure of ZnO in the composites. The chemical states and the valence of the species in the C–ZnO/V
2
O
5
composite have been confirmed by XPS analysis. The catalytic performance of the synthesized nanocomposite photocatalysts against organic dye degradation under visible-light exposure has been investigated. The C–ZnO/V
2
O
5
nanocomposite photocatalyst exhibited improved catalytic performance over bare ZnO and V
2
O
5
. Based on the recycling experiments, the stability of the as-synthesized photocatalyst was confirmed toward the degradation of organic contaminants. The significant role of reactive species in the photocatalysis degradation process was confirmed from the trapping experiments. The interfacial contact between the ZnO and V
2
O
5
helps to separate the charge carriers and actively participates in the photocatalytic degradation process.
Nitrophenols has become a significant threat to the ecosystem and the health of the human beings. Photocatalytic degradation is considered to be the utmost competent approach for the amputation of ...nitroaromatic pollutants. In this research, 2-nitrophenol (MNP), 2,4-dinitrophenols (DNP), and 2,4,6-trinitrophenol or picric acid (PA) are taken for the degradation studies using the photo-Fenton catalyst of synthesized TiO
2
nanoparticle modified with biopolymer containing organic and inorganic functionalities. The morphological study reveals the uniformly distributed TiO
2
nanoparticles (15 nm) surfaces are encapsulated by the active site-rich chitosan-ligand-copper complex facilitating more absorption and enhancing the photocatalytic activity toward the target molecules. The UV spectra confirm the predominant shifting of absorption peak in the range 305–310 nm which results due to the formation of TiO
2
-CBGCu nanocomposites. The zeta potential of the synthesized nanocomposites TiO
2
-CBGCu 5%, TiO
2
-CBGCu 10%, and TiO
2
-CBGCu 20% are − 12, − 20, and − 29 mV which reveals that the value increases with the increase in CBGCu content which in turn signifies the more stability in aqueous solution. Amid the prepared nanocomposites, TiO
2
-CBGCu 10% demonstrates the imperative catalytic performances toward MNP, DNP, and PA pollutants along with the Fenton’s reagent at pH 3.0 under visible light and solar light. It shows effective degradation for strong acid PA within 18 min in visible light compared to MNP and DNP due to the presence of more active sites in the synthesized nanocomposites. This work has created awareness about the multifunctional catalyst and the effectiveness of the same has opened a new passage to eliminate nitrophenols from the agonized environment.
In the present study, Graphene Oxide (GO) was prepared by the modified Hummer’s method. Further, different wt% of reduced Graphene Oxide (rGO) decorated TiO
2
(TiO
2
-rGO) nanocomposites were ...synthesized using non-toxic sodium L-ascorbate as a reducing agent. The structure, morphology, optical and chemical composition of the composites were investigated with analytical techniques such as XRD, FESEM, HRTEM, UV –Vis DRS, FTIR, XPS and Raman spectroscopy. The zeta potential study reveals that the surface charge of the materials is negative and the value increases with the increase in the rGO content which proves residual acid groups on rGO and by the decoration of rGO surface with TiO
2
. The photocatalytic activity of the composites was tested for the degradation of nitrophenols Mononitrophenol (MNP), Dinitrophenol (DNP) and Picric Acid (PA) in the presence of the Fenton’s reagent with UV light (wavelengths 254 and 390 nm), visible light and sunlight at different pHs (3,7 and 10). In the presence of Fenton’s reagent, the catalyst TiO
2
-rGO 1% exhibited 100% degradation of nitrophenols in UV light of wavelength 254 nm within 15 min whereas with sunlight the catalysts, TiO
2
-rGO 5% and TiO
2
-rGO 10% exhibited 100% degradation of nitrophenols within 15 min and 18 min, respectively, at pH 3. Thus, the combined catalysts could have much impact on the photocatalytic degradation of water-borne organisms in the future.
Graphical abstract
Carbon-doped ZnO nanoparticles were synthesized through different carbon precursors namely fullerene, glucose, and sucrose via hydrothermal method. The presence of carbon in the ZnO lattice was ...confirmed by the shifting of diffraction peaks and micro Raman characteristic peak of ZnO towards the lower values. XPS spectra confirms the Zn–O–C bond from the shifting of binding energy peaks towards the higher value for C-ZnO due to the variation in the electronegativity values of C and O. Based on the elemental analysis and photoluminescence studies, the deficiency of O and Zn in ZnO was confirmed while ZnO doped with carbon. The visible-light catalytic performance of the prepared photocatalysts for the mineralization of organic dye was studied. Carbon plays a significant contribution to enhance the photocatalytic activity and photostability of pristine ZnO till fourth cycle by overcoming the photocorrosion of ZnO because of its environmental and biological friendly nature. The trapping experiments were employed to demonstrate the degradation process and the possible photocatalysis mechanism.
For the first time, C-ZnO/BiVO4 heterostructured nanocomposite has been synthesized from BiVO4 and carbon-doped ZnO nanoparticles. X-ray diffraction (XRD) study showed themonoclinic scheelite ...structure of BiVO4 and the hexagonal wurtzite structure of ZnO in the C-ZnO/BiVO4 composite. Field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) images revealed the spherical nanoparticles of size 20 to 30 nm for C-ZnO. The band gap of the ZnO has turned towards the visible region by doping with carbon as well as a composite formation with visible light active material BiVO4. The chemical states of Zn, O, C and Zn, O, C, Bi, V species in C-ZnO, and C-ZnO/BiVO4 composite respectively were confirmed by X-ray photoelectron microscopy (XPS) analysis. Also, the XPS spectra showed the significant peaks shift in the electronic states of Zn, O, and C for the heterojunction composite. The suppression of the electron-hole recombination rate was confirmed from the quenching of photoluminescence (PL) intensity for the composite. The adsorption study has performed, and the experimental results fit well with the Langmuir isotherm model for understanding the catalytic activity of the samples. The possible Z-scheme photocatalytic mechanism of the C-ZnO/BiVO4 nanocomposite photocatalyst has proposed. The nanocomposite exhibited the enhanced catalytic activity with the higher degradation rate constant of 0.050 min−1 for 50 min irradiation of visible light compared with their counterparts.
•C-ZnO/BiVO4 nanocomposite has higher pseudo first order kinetic rate constant.•The band gap of ZnO can be tuned into visible light via the formation of composite.•The influence of C and BiVO4 in ZnO and their catalytic performances against MB dye.•The formation of hetero-junction suppressed the electron–hole recombination rate.
