First-principles calculations and experimental investigation on SnO2@ZnO heterojunction photocatalyst with enhanced photocatalytic performance

In this study, branch-like SnO₂@ZnO heterojunction photocatalyst was successfully fabricated via a simple two-step hydrothermal process. The optical and electronic properties were characterized in detail and the results indicated that SnO₂@ZnO nanocomposites (TZNCs) exhibited superior photocatalytic performance under visible light irradiation as compared to pure SnO₂ and ZnO. The excellent photocatalytic performance of TZNCs can be ascribed to the heterojunction structure between ZnO and SnO₂ which depresses the recombination of photogenerated electron-hole pairs. In addition, the branch-like morphology can provide large specific surface. Moreover, the density functional theory (DFT) computation on the Fermi level results confirmed that heterojunction structure between ZnO and SnO₂ is more favor of the transfer of photogenerated eletrons from ZnO to SnO₂, effectively improving separation of photogenerated electron-hole pairs. Noteworthy, this work would pave the route for the two semiconductor materials with a big work function difference which would lead to the high contact potential difference, surely contributing to improving the performance of photocatalysts.

Crystal phase content-dependent functionality of dual phase SnO2-WO3 nanocomposite films via cosputtering crystal growth

In this study, crystalline SnO2-WO3 nanocomposite thin films were grown through radio-frequency cosputtering of metallic Sn and ceramic WO3 targets. The W content in the SnO2 matrix was varied from 5.4 at% to 12.3 at% by changing the WO3 sputtering power during thin-film growth. Structural analyses showed that increased WO3 phase content in the nanocomposite films reduced the degree of crystallization of the SnO2 matrix. Moreover, the size of the composite films' surface crystallites increased with WO3 phase content, and the large surface crystallites were composed of numerous nanograins. Addition of WO3 crystals to the SnO2 matrix to form a composite film improved its light harvesting ability. The SnO2-WO3 nanocomposite films exhibited improved photodegradation ability for Rhodamine B dyes compared with their individual constituents (i.e., SnO2 and WO3 thin films), which is attributable to the suitable type II band alignment between the SnO2 and WO3. Moreover, an optimal WO3 phase content (W content: 5.4 at%) in the SnO2 matrix substantially enhanced the ethanol gas-sensing response of the SnO2 thin film. This suggested that the heterojunctions at the SnO2/WO3 interface regions in the nanocomposite film considerably affected its ethanol gas-sensing behavior.

New strategy towards the assembly of hierarchical heterostructures of SnO2/ZnO for NO2 detection at a ppb level

The SnO₂/ZnO hierarchical heterostructures (HHSs) were synthesized via the microwave-assisted hydrothermal method, and the SnO₂/ZnO HHSs based sensor exhibited ultra-low detection limit of 2 ppb for detecting NO₂.

Porous Au/ZnO nanoparticles synthesised through a metal organic framework (MOF) route for enhanced acetone gas-sensing

Porous Au/ZnO nanoparticles through a simple metal organic framework route show high response and selectivity towards low concentration acetone.

Nanoporous ZnO nanostructure synthesis by a facile method for superior sensitivity ethanol sensor applications

Nanoporous ZnO nanostructures prepared by thermal decomposition of plate-like hydrozincite showed superior sensitivity to ethanol for lung cancer diagnosis.