Ultra-sensitive gas sensor enabled by architectural and electronic synergy in bio-templated ZnO/hollow carbon microtubules

The development of high-performance gas sensors using sustainable materials is of significant importance for environmental monitoring. This work reports a one-pot zinc acetate-assisted pyrolysis and carbonization method to prepare dandelion crown hair fiber-derived carbon microtubes (DFCMT) and their zinc oxide heterojunction composites (ZnO/DFCMT) from dandelion crown hair fibers (DCHF). The unique hollow structure of the DFCMT serves as an excellent scaffold, facilitating the mass transfer of gas molecules. More importantly, the adopted strategy simultaneously achieves carbonization and the in-situ formation of uniformly dispersed ZnO nanoparticles, effectively preventing agglomeration and creating abundant heterointerfaces. When evaluated as gas sensors, the optimized ZnO/DFCMT heterojunction exhibited remarkable enhancement in sensing performance towards four target gases, including ethylene glycol, showing 5.0–13.6 fold and 3.4–16.9 fold higher response compared to the pristine DFCMT and pure ZnO, respectively. Notably, the sensor demonstrated an ultra-low detection limit of 0.027 ppm for ethylene glycol, high sensitivity, and excellent long-term stability over 30 days. The significantly improved performance is primarily attributed to the synergistic effects of the hierarchical hollow structure and the formed heterojunctions, which promote gas adsorption and electron transfer. This work provides a sustainable and efficient strategy for designing advanced heterostructure materials for high-performance environmental sensing applications.