Formation via Oriented Attachment Process and Photocatalytic Activity of Small and Crystalline Spherical SnO2 Nanoparticles

Photocatalysis is an innovative method for environmentally friendly wastewater treatment. A development of modern photocatalyst, which is suitable for industrial water purification from hazardous organic compounds, is a global challenging problem. Novelty of this work is in the development of synthetic approach based on hydrothermal treatment in a combination with computational experiment. Oriented attachment mechanism was engaged via hydrothermal treatment to produce SnO2 nanoparticles out of preliminary obtained initial blocks - smaller SnO2 nanoparticles, obtained via precipitation method. The initial blocks and obtained nanoparticles were studied with a large set of methods, such as XRD, FTIR, SSA, HRTEM, XPS, and Raman spectroscopy. The oriented attachment mechanism was studied using a computational method, based on the earlier developed approach, revealing the role of ions, existing in the reaction media, and the path of nanoparticle formation. Initial blocks and obtained nanoparticles were tested as photocatalysts on test solutions of organic dyes (methylene blue, rhodamine 6G and congo red). The more complex the dye structure, the more difficult is photocatalytic decomposition of its molecule. However, optimization of the extraction procedure allowed to achieve up to 90% extraction efficiency.