Mesoporous WS 2 /MoO 3 Hybrids for High-Performance Trace Ammonia Detection.

Mesoporous WS 2 /MoO 3 hybrids were synthesized by a facile two-step and additive-free hydrothermal approach and employed for high-performance trace ammonia gas (NH 3 ) detection. Compared with single WS 2 and MoO 3 counterparts, WS 2 /MoO 3 sensors exhibited an improvement in NH 3 -sensing performance at room temperature (22 ± 3 °C). Typically, the optimal WS 2 /MoO 3 sensor showed a higher and quicker response of 31.58% within 57 s toward 3 ppm of NH 3 , which was 17.7- and 57.4-fold larger than that of pure MoO 3 (1.78% within 251 s) and WS 2 (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 WS 2 and MoO 3 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 WS 2 /MoO 3 heterostructure nanomaterials have the potential in achieving trace NH 3 recognition catering for the requirements of high sensitivity and low power consumption in future gas sensors.