Effect of SnO Composition in SnO/SnO₂ Nanocomposites on the Photocatalytic Degradation of Malachite Green under Visible Light

Abstract

Three types of SnO/SnO2 nanocomposites with different component ratios were synthesized using a simple hydrothermal process. Three samples, S1, S2, and S3, were produced by optimizing the occupied volume inside the Teflon flask, and are referred to as SnO2 rich, intermediate level, and SnO rich, respectively. In terms of degradation of malachite green under visible light, the photocatalytic activity of the S2 sample outperforms the other two samples and pure SnO by 30 %. It is attributed to the fact that the S2 sample has the most heterojunction between p‐type SnO and n‐type SnO2 of the three samples because the formation of p‐type SnO and n‐type SnO2 heterojunction in S2 prevents photogenerated electron‐hole recombination. By comparing S1 and S3 samples, we figured out that Sn2+ doped into the SnO2 lattice acts as an electron trap, slowing the recombination process and increasing photocatalytic activity.

1D Narrow-Bandgap Tin Oxide Materials: Systematic High-Resolution TEM and Raman Analysis

“…When the reaction temperatures in the precursor synthesis and the amount of tin source were 0 • C and 0.11 g, 60 • C and 0.06 g, 60 • C and 0.22 g, and 60 • C and 0.11 g, respectively, the lower bandgap was estimated to be 2.9~3.0 eV except for the largest amount of tin source (0.06 g). The narrower bandgaps observed in the calcination samples were similar to those of reported SnO bandgaps (2.8-3.0 eV) [12]. For longer calcination conditions, a marked increase in bandgap was clearly observed only for 0.06 g of tin source as a result of the enhanced oxidation of the tin oxides.…”

“…In recent years, tin oxide nanocomposites (SnO/SnO 2 ) have received much attention because of their potential applications as p-n junction photocatalysts due to their visible-light absorbing properties [ 12 ]. Regarding photocatalysts of tin oxides, SnO 2−x nanocrystals with oxygen vacancies have also been designed for introducing defect centers, as well as for controlling band structures to improve their reactivities.…”