Emerging strategies in MoO3 nanostructured gas sensors: a review of morphology engineering and hybrid interface design
A. H. Farahani, R. Zarei Moghadam
Abstract
This review summarizes recent advances in molybdenum trioxide (MoO3) nanostructured gas sensors, focusing on three key strategies for performance enhancement: (i) morphology engineering for sensitivity optimization, e.g., nanobelts achieving a response of 49 to 5 ppm H₂S at 250 °C; (ii) heterojunction engineering for selectivity, e.g., MoO3/ZnO showing ten-fold higher selectivity for NO₂ over CO at 100 ppm; and (iii) heterojunction engineering for environmental robustness, e.g., MoO3/rGO (reduced graphene oxide, a highly conductive carbon-based material) exhibiting a response of 843 to 100 ppm ethylenediamine at room temperature (23 °C). The review also discusses synthesis methods, gas adsorption mechanisms, and critical challenges such as humidity interference (10–20% sensitivity reduction at 50% relative humidity) and cross-sensitivity. By integrating recent findings into a structured framework, we highlight research gaps and suggest future directions toward low-power, highly selective sensors, including artificial intelligence-assisted designs for real-world applications.