One-step hydrothermal synthesis of Fe2(MoO4)3 functionalized α-MoO3 nanoplates with enhanced gas sensing properties

• 2D Fe 2 (MoO 4 ) 3 /α-MoO 3 heterojunctions were synthesized via a simple one-step hydrothermal method. • Fe 2 (MoO 4 ) 3 nanoparticles were uniformly distributed on the α-MoO 3 nanoplate surface. • The heterojunction sensor showed a ∼3 times higher response to ethanol than pure α-MoO 3 . • The sensor also exhibited fast response/recovery and excellent long-term stability. • The enhancement is attributed to the formed heterojunction and the catalytic effect of Fe 2 (MoO 4 ) 3 . The synthesis method for heterojunctions is usually a two-step method, typically involving the synthesis of a support first, followed by the loading of metal oxides or metal molybdates. In this study, we propose a simple one-step hydrothermal method for preparing two-dimensional (2D) Fe 2 (MoO 4 ) 3 -functionalized α-MoO 3 nanoplates in the presence of lactic acid, without the need to add surfactants or templates. To examine the microstructure, morphology, and chemical compositions of the Fe 2 (MoO 4 ) 3 /α-MoO 3 heterostructures, a variety of techniques were utilized. The experimental results confirm that the Fe 2 (MoO 4 ) 3 /α-MoO 3 heterojunctions are successfully obtained, and the Fe 2 (MoO 4 ) 3 nanoparticles display uniform distribution over the α-MoO 3 surface as the loading amount is appropriate. Gas sensing tests for several typical organic gases demonstrated that the Fe 2 (MoO 4 ) 3 /α-MoO 3 -based sensor had significantly higher responses to ethanol and acetone than the pure α-MoO 3 -based sensor. Moreover, it also showed rapid response − recovery speeds, as well as good reproducibility and stability, suggesting its potential in gas sensing applications. The outstanding gas sensing performance might be attributed to the existence of α-MoO 3 -Fe 2 (MoO 4 ) 3 heterojunctions and the catalytic effect of Fe 2 (MoO 4 ) 3 nanoparticles.