A synthetic approach to obtain nanoparticles of different sizes and shapes via hydrothermal treatment was developed. It was shown that hydrothermal treatment engage oriented attachment mechanism of nanoparticle formation. Obtained nanoparticles were filly characterized by a wide set of methods, their structural parameters were studied and correlations of later with the synthesis procedure were shown. A series of nanoparticles of various sizes and shapes were tested as photocatalysts for cyclic organic pollutants. Fast photodegradation (100% within 10 min) of methylene blue and rhodamine 6G under UV light was achieved. Degradation mechanism was studied, taking into account adsorption stage, pollutant-nanoparticle surface interactions and vacancies to defects ratio, involving computer calculations. A key factor affecting photocatalytic efficiency was revealed.