Ppb-level n-butanol sensors based on UV-activated Gd:Tourmaline@MOF-ZnO core–shell composites

Developed a unique Gd-doped Tourmaline@MOF-ZnO nanostructure that integrates a polarized core with a highly porous shell. • Achieved a massive response (890.31 to 100 ppm), fast kinetics (34 s/18 s), and a ppb-level detection limit (56.63 ppb) for n-butanol at 240 °C under UV activation. • The gas-sensing performance is significantly boosted through the synergistic combination of the MOF-derived porous architecture, Tourmaline polarization, Gd-induced oxygen vacancies, and UV activation. Reliable monitoring of volatile organic compounds (VOCs) demands gas sensors with fast response, high sensitivity, and excellent selectivity. To this end, we designed a novel gas-sensing material based on a Gd-doped Tourmaline@MOF-ZnO core–shell nanostructure. This structure integrates a Tourmaline core with a porous MOF-derived ZnO shell, further enhanced via Gd doping. The gas sensing properties were evaluated under both dark condition and UV activation. At the operating temperature of 240 °C with UV activation, the optimized sensor with 0.08 wt% Gd and 5 wt% Tourmaline (denoted as 0.08 wt% Gd-5 wt% TML@ZnO) exhibited a remarkable response of 890.31 to 100 ppm n-butanol. This value is 9.96 times higher than that of the pristine MOF-derived ZnO (89.43). Moreover, the sensor demonstrated fast response/recovery times (34 s/18 s), high selectivity, excellent long-term stability, and a low detection limit of 56.63 ppb. The outstanding performance underscores the considerable promise of the optimized Gd-doped Tourmaline@MOF-ZnO core–shell composite for practical ppb-level VOCs monitoring. This work provides an effective strategy for designing high-performance gas sensors through the synergistic integration of rare-earth doping and core–shell structural design. Download: Download high-res image (214KB) Download: Download full-size image