Photocatalysis is a recognized technique for wastewater purification from hazardous organic compounds. Development of the photocatalysts faces several challenges, among which are efficiency and shift of activation range towards visible light. In the work an approach to synthesis of Cu-doped SnO ₂ nanoparticles with various amount of dopant and different formation rates, which lead to production of nanoparticles with different amount of defects is developed. Approaches to evaluate amounts of oxygen vacancy and defects from XPS and Raman spectra are suggested, approbation of the approaches was carried out and dependencies of the amounts of oxygen vacancy and defects on dislocation density were revealed, which allows to regulate them via changes in synthesis parameters. A ratio of oxygen vacancies and defects was revealed as a main factor impacting photocatalysis in the case of the Vis-driven nanoparticles of the same size and shape, which can be further used for rational design of nanomaterials for waste water treatment. Quantitative defect-related dependencies of the conductivity and capacity were shown. A sample was obtained with structural parameters providing capacity equal to 1178 mAh·g ⁻¹ close to theoretically calculated.