Mesoporous WS₂/MoO₃ Hybrids for High-Performance Trace Ammonia Detection

Mesoporous WS₂/MoO₃ hybrids were synthesized by a facile two-step and additive-free hydrothermal approach and employed for high-performance trace ammonia gas (NH₃) detection. Compared with single WS₂ and MoO₃ counterparts, WS₂/MoO₃ sensors exhibited an improvement in NH₃-sensing performance at room temperature (22 ± 3 °C). Typically, the optimal WS₂/MoO₃ sensor showed a higher and quicker response of 31.58% within 57 s toward 3 ppm of NH₃, which was 17.7- and 57.4-fold larger than that of pure MoO₃ (1.78% within 251 s) and WS₂ (0.55% within 153 s) ones. Meanwhile, good reversibility, sensitivity, and selectivity, reliable long-term stability, and the lowest detection limit of 9.0 ppb were achieved. These superior properties were probably ascribed to numerous heterojunctions favorable for additional carrier-concentration modulation via the synergetic effect between WS₂ and MoO₃ components and the large specific surface area beneficial for richer sorption sites and faster molecular transfer at room temperature. Such achievements also imply that the designed WS₂/MoO₃ heterostructure nanomaterials have the potential in achieving trace NH₃ recognition catering for the requirements of high sensitivity and low power consumption in future gas sensors.