Synthesis mechanism of nanoporous Sn₃O₄ nanosheets by hydrothermal process without any additives

Nanoporous anorthic-phase Sn₃O₄ nanosheets are successfully fabricated via a hydrothermal process without any additives. With the pH value of the precursor increasing from 2.0 to 11.8, the valence of the precursor changes from mixed valence (the ratio of Sn²⁺ to Sn⁴⁺ is 2.7:1) to pure bivalent, and the product transformed from Sn₃O₄ to SnO mesocrystals. When doping SbCl₃ to the alkaline precursor, the valence of the precursor shows mixed valence with the ratio of Sn²⁺ to Sn⁴⁺ being 2.6:1 and Sn₃O₄ is synthesized after the hydrothermal process. The valence state of Sn species in the precursor is the key factor of the formation of Sn₃O₄. The synthesis mechanism is discussed and proposed. These experimental results expand the knowledge base that can be used to guide technological applications of intermediate tin oxide materials.