Search

Graphical abstract Highlights • SnS 2 /ZIF-8 derived porous flower-like SnO 2 /ZnO heterostructures were obtained. • New self-assembled SnS 2 flower-like microstructures were used as templates. • SnO 2 /ZnO composites exhibit high sensitivity and selectivity to TEA at 200 °C. • Tunable morphology and n–n heterojunctions play a key role for gas sensing property. • The method can be used for obtaining other heterostructures with novel shapes. Abstract SnO 2 -based flower-like sensitive materials derived from the self-assembled SnS 2 microstructures with more active areas and less agglomeration represent an alternative option for new generation of gas sensors. Meanwhile, the introduction of ZIF-8 for semiconductor surface functionalization is expected to get multi-functional hybrid materials with synergistic effects of individual components. In the present work, SnS 2 /ZIF-8 derived porous flower-like SnO 2 /ZnO heterostructures have been synthesized by a facile template method and the subsequent heat-treatment process. Beside the uniform morphology with tunable composition and size distribution, the attractive findings are focused on the enhanced triethylamine (TEA) gas-sensing properties of the obtained composites. SnO 2 /ZnO heterostructures show an obvious improvement in TEA gas sensing performance at the operating temperature of 200 °C, giving a response of about 17.7–50 ppm TEA, which was about 2.2 times higher than that of the sensors based on pure SnO 2. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cubic-like In 2 O 3 /α-Fe 2 O 3 composites assembled with porous nanoplates are obtained. • The introduction of Fe3+ component plays a vital role for morphological evolution. • In 2 O 3 /α-Fe 2 O 3 composites display superior TEA gas-sensing behavior at 170 °C. • In/Fe-2 shows the highest response and excellent cycling and long-term stability. • Sensing mechanism mainly depends on the unique microstructure and heterojunction. Cubic-like In 2 O 3 /α-Fe 2 O 3 heterostructures assembled with 2D porous nanoplates have been prepared by solvothermal method and subsequent calcination process. The introduction of Fe3+ component plays an important role for the morphological evolution of In 2 O 3 -based samples with unique crystal nucleation and growth mechanism. Compared with flower-like In 2 O 3 self-assemblies composed of tower-like structural units, In 2 O 3 /α-Fe 2 O 3 composites can display superior trimethylamine (TEA) gas-sensing behavior. For example, the optimal working temperature is reduced from 250 to 170 °C, and the response value of In/Fe-2 materials is 375.43, which is about 6.23 times than that of In 2 O 3 sensors. The enhanced gas-sensing properties are mainly attributed to large specific surface area (234.4 m2/g), the effective In 2 O 3 -α-Fe 2 O 3 heterojunctions, unique surface/interface effects, and tunable electron transmission mechanism. [ABSTRACT FROM AUTHOR]

Morphology-controlled porous α-Fe 2 O 3 /SnO 2 nanorods with uniform surface heterostructures have been fabricated by a facile surface modification of rod-like α-Fe 2 O 3 nanomaterials by changing the adding amount of Sn composition, displaying the excellent selectivity and sensitivity of gas-sensing to acetone. The introduction of SnO 2 nanoparticles had the great effects on tuning the crystal size, crystallinity, and surface status, as well as the structural stability and phase distribution of α-Fe 2 O 3 /SnO 2 nanorods. Compared to pure α-Fe 2 O 3 , α-Fe 2 O 3 /SnO 2 heterostructures can exhibit the optimal gas-sensing behavior with the sensitivity up to 53.1 and the response and recovery times decreasing to 9 and 2.5 s at the operating temperature of 260 °C, respectively. The enhanced gas-sensing performance can be mainly attributed to the combination of uniform porous structures, narrow size-distribution, large specific surface area, and heterostructures of the interface between α-Fe 2 O 3 and SnO 2 . [ABSTRACT FROM AUTHOR]