The flower-like

h

-MoO

3

nanorods are prepared by chemical bath deposition method from ammonium molybdate solution

the surface morphology and crystal structure of the products are characterized using scanning electron microscope(SEM)and Raman spectroscopy

the effects of the solution concentration on the surface morphology and crystal structure of

h

-MoO

3

are then discussed

the formation mechanism is studied.Subsequently

an ammonia(NH

3

)sensor is prepared by the deposition of

h

-MoO

3

nan

orods on the large-area chemical vapor deposition(CVD)-grown graphene film

and the gas-sensitive performance of the prepared

h

-MoO

3

@graphene sensor is measured by the customized test platform.The results indicate that the sensitivity of this sensor is significantly better than the pure graphene-based ammonia sensor.It shows robust response to ammonia concentrations as low as 1×10

-6

at room temperature

and it shows good repeatability ammonia concentration range of (1~30)×10

-6

.