Construction of Co3O4/Fe3O4 heterojunctions from metal organic framework derivatives for high performance toluene sensor

Ultrasensitive and Exclusive Chemiresistors with a ZIF-67-Derived Oxide Cage/Nanofiber Co3O4/In2O3 Heterostructure for Acetone Detection

“…The dominant type of oxygen ion depends directly on the operating temperature. The reaction process is shown in eqs – normalO 2 false( normalg false) ⇌ normalO 2 ( ads ) normalO 2 false( ads false) + normale − ⇌ O 2 − ( ads ) goodbreak0em1em⁣ ( T < 100 0.25em ° C ) O 2 − false( ads false) + normale − ⇌ 2 normalO − ( ads ) goodbreak0em1em⁣ ( 100 0.25em ° C ≤ T < 300 0.25em ° C ) O − ( ads ) + e − ⇌ O 2 − ( ads ) goodbreak0em1em⁣ ( T ≥ 300 0.25em ° C…”

“…10,31,32 Co-based zeolitic imidazolate framework (ZIF-67) is one of the most typical examples, which can be converted into Co 3 O 4 with advantages, such as simple preparation, environmentally nontoxic, and structurally stable. 28,30 Therefore, here, we constructed a unique heterostructure to enhance the sensing performance of We evaluated the morphology, composition, and elemental species of In 2 O 3 , Co 3 O 4 , and CIO-X samples. Scanning electron microscopy (SEM) images in Figures 2a and S1a,b and transmission electron microscopy (TEM) images in Figure S2a show the morphology of the In 2 O 3 nanofibers with a uniform diameter of about 130 nm.…”

“…However, pristine In 2 O 3 nanostructures exhibit relatively poor response, low selectivity, and low detection limit toward acetone. To enhance the sensing performance of In 2 O 3 nanostructures, several strategies have been proposed, such as constructing different heterogeneous structures, 10,11,14,30 decorating noble metal catalysis, 15 designing charge transfer hybrids, and introducing molecular detection and screening effects. It is noted that metal oxide nanostructures derived from metal−organic frameworks (MOFs) could be good sensing materials considering their unique hollow structure.…”

“…However, pristine In 2 O 3 nanostructures exhibit relatively poor response, low selectivity, and low detection limit toward acetone. To enhance the sensing performance of In 2 O 3 nanostructures, several strategies have been proposed, such as constructing different heterogeneous structures, ,,, decorating noble metal catalysis, designing charge transfer hybrids, and introducing molecular detection and screening effects. It is noted that metal oxide nanostructures derived from metal–organic frameworks (MOFs) could be good sensing materials considering their unique hollow structure. ,, Co-based zeolitic imidazolate framework (ZIF-67) is one of the most typical examples, which can be converted into Co 3 O 4 with advantages, such as simple preparation, environmentally nontoxic, and structurally stable. , Therefore, here, we constructed a unique heterostructure to enhance the sensing performance of In 2 O 3 to acetone by using In 2 O 3 nanofibers and a ZIF-67-derived hollow Co 3 O 4 cage.…”

Nanostructured metal oxide heterojunctions for chemiresistive gas sensors

“…Liu et al successfully constructed porous Co 3 O 4 /Fe 3 O 4 nanostructures with different ratios using a two-step solution-based hydrothermal method. 90 Fig. 5c shows that after modification with different ratios of Co 3 O 4 , the specific surface area and toluene-sensing performance of Fe 3 O 4 improved, displaying the reduction of operating temperature and the enhancement of sensitivity in the analysis of toluene.…”