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

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