Defect-Mediated Cobalt-Doped SnO₂ Nanostructures for Enhanced Visible-Light Photocatalytic Degradation
DOI:
https://doi.org/10.56919/usci.2651.023Keywords:
SnO₂ nanostructures, cobalt doping, defect engineering, visible-light photocatalysis, Rhodamine B, kineticsAbstract
The development of visible-light-responsive photocatalysts is essential for sustainable wastewater remediation. In this study, defect-engineered cobalt-doped SnO₂ nanostructures were synthesized via a co-precipitation method and evaluated for the photocatalytic degradation of Rhodamine B. X-ray diffraction analysis confirmed the formation of a tetragonal rutile phase, while peak shifts and broadening in the doped sample indicated lattice distortion and reduced crystallite size. X-ray photoelectron spectroscopy revealed the presence of Co²⁺ species, mixed Sn⁴⁺/Sn²⁺ oxidation states, and abundant oxygen vacancies, confirming successful defect formation. Under visible-light irradiation, the 2 mol% Co–SnO₂ exhibited significantly enhanced photocatalytic performance, achieving approximately 99% degradation within 300 minutes, compared to ~80% for pristine SnO₂. Kinetic studies showed that the degradation follows pseudo-first-order behavior, with a rate constant of 0.00557 min⁻¹ for the doped sample, corresponding to an approximately 2.6-fold improvement. The enhanced activity is attributed to defect-induced charge separation, improved visible-light absorption, and suppressed electron–hole recombination. These results demonstrate that cobalt-induced defect engineering is an effective strategy for enhancing the photocatalytic efficiency of SnO₂ nanostructures for environmental applications.
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