Hollow Co3O4 nanocubes incorporated into porous ZnO nanotubes for selectively enhanced gas sensing toward BTEX

Benzene, toluene, ethylbenzene, and m-xylene (BTEX) are typical volatile organic compounds (VOCs) that pose serious threats to human health. However, their inherent chemical stability and low reactivity render selective and sensitive detection particularly challenging. Herein, we report a p–n heterostructured gas sensing material comprising hollow Co 3 O 4 nanocubes embedded in porous ZnO nanotubes (Co 3 O 4 /ZnO NTs), fabricated via coaxial electrospinning and Metal-organic frameworks (MOFs)-derived pyrolysis. The engineered architecture combines the large surface area and porosity of ZnO nanotubes with the abundant active sites of Co 3 O 4 , facilitating efficient gas diffusion and charge transport. The resulting sensors exhibit markedly enhanced responses to BTEX gases, particularly ethylbenzene. At 50 ppm, the responses to benzene, toluene, ethylbenzene, and m-xylene are 2.3, 12.2, 46.5, and 30.9 times higher, respectively, than those of pristine ZnO nanotubes. In addition, the sensor demonstrates excellent selectivity for ethylbenzene and stable long-term operation. This work demonstrates an effective strategy for tuning oxide heterojunctions toward high-sensitivity, selective detection of aromatic VOCs, offering practical value for environmental monitoring.