7th Commonwealth Chemistry Posters

Tailoring CoNb₂₋ₓMoₓO₆ Columbite Oxides for High-Efficiency Dye Degradation in Wastewater Treatment

Nimra Maqsood^a and Uzma Hira^b

^aSchool of Physical Sciences, University of the Punjab, New Campus, 54590, Lahore, Pakistan

^bSchool of Chemistry, University of the Punjab, New Campus, 54590, Lahore, Pakistan

Introduction

Dye-contaminated industrial wastewater poses serious environmental and health risks.
Semiconductor photocatalysis offers a sustainable approach for degrading organic pollutants into harmless products.
Columbite-type CoNb₂O₆ is a stable photocatalyst, but its wide band gap limits photocatalytic efficiency.
Mo doping can tune the electronic structure, improve light absorption, and enhance charge-carrier separation.
This work investigates the effect of Mo substitution on the structural, optical, and photocatalytic properties of CoNb₂₋ₓMoₓO₆ for Brilliant Green dye degradation.

Objective

To synthesize and optimize Mo-doped CoNb₂₋ₓMoₓO₆ photocatalysts and evaluate the effect of Mo substitution on their structural, optical, and photocatalytic properties for efficient Brilliant Green dye degradation in wastewater.

Methodology

Pechini Sol-gel method.

Photocatalysis

Photocatalytic degradation efficiency increased with Mo concentration, reaching 91.43% for CoNb₁.₈₀Mo₀.₂₀O₆ after 120 min of UV irradiation.
Kinetic analysis followed pseudo-first-order behavior, with the rate constant increasing from 0.0075 to 0.0189 min⁻¹.

Analysis

XRD & Rietveld Refinement: Crystal structure and crystallite size.
SEM: Surface morphology and microstructure.
FTIR: Metal-oxygen bond verification.
UV-Vis: Optical properties and band gap.

XRD & Rietveld Refinement

Single-phase orthorhombic structure
Lattice contraction with Mo doping
Rietveld refinement confirmed the formation of phase-pure orthorhombic CoNb₂₋ₓMoₓO₆ (Pbcn) and revealed Mo-induced lattice contraction and crystallite size reduction.

SEM Analysis

Morphological evolution
Grain growth

FTIR analysis

NbO₆/MoO₆ vibrations
Structural integrity

UV–Vis/Tauc Plot

Mo doping progressively reduced the optical band gap from 3.14 eV to 2.68 eV.

Results/Findings

Single-phase orthorhombic columbite structure retained.

Band gap narrowed: 3.14 → 2.68 eV

Enhanced visible-light absorption.

Brilliant Green degradation: 62.54% → 91.43%

Reaction rate increased: 0.0075 → 0.0189 min⁻¹

Conclusion

Mo-doped CoNb₂O₆ emerged as a promising photocatalyst for efficient dye degradation, offering a sustainable pathway for advanced wastewater treatment.

Acknowledgments

Supervisor, lab members, funding/support institutions

References

De, A., M.A. Rambaran, and C.A. Ohlin, Fabrication and Electrocatalytic Evolution of Alkali-Free CoNb₂O₆ Thin Films for Water Oxidation via Polyoxoniobates. ACS Applied Energy Materials, 2024. 7(19): p. 8333-8341.
Ravi, P. and J.S. Noh, Recent Progress and Future Perspectives of MNb₍₂₎O₍₆₎ Nanomaterials for Photocatalytic Water Splitting. Materials (Basel), 2025. 18(15).

7th Commonwealth Chemistry Posters

Tailoring CoNb₂₋ₓMoₓO₆ Columbite Oxides for High-Efficiency Dye Degradation in Wastewater Treatment

Poster Presenter

Authors

Affiliations

Part of Topic