Preparation And Gas Sensitivity Of Molybdate Nanomaterials

The specific structure of the multi-metal oxide rapidly adsorbs a specific gas and cause selective oxidation.This property can solve the problems of slow response-recovery and poor selectivity of simple metal oxides.NaBi?MoO₄?₂ nanomaterials were prepared by solvothermal synthesis method.XRD,SEM,TEM,BET and Raman test techniques are used to systematically study the influence of the morphology and structure of NaBi?MoO₄?₂nanomaterials on the gas-sensitive properties of NaBi?MoO₄?₂ nanomaterialsIn this paper,The synthesis conditions of NaBi?MoO₄?₂ by solvent thermal method and its gas sensitivity to n-butanol are studied.The best synthesis conditions were found to synthesize NaBi?MoO₄?₂ powder materials.After XRD,SEM,TEM and other characterization,it was indicated that the size of the powder particles was about 100nm long and 20 nm wide nanorods,and the particles were well dispersed without obvious agglomeration.The gas sensitivity test of 100 ppm n-butanol gas was carried out on a pure NaBi?MoO₄?₂ gas sensor.When the operating temperature was 370°C,the sensitivity was the highest,about 35.2.At this time,the sensor's response to recover faster performance,response to the recovery time of 5 s and 10 s respectively.Then,the gas sensing properties of MWCNTs composite NaBi?MoO₄?₂nanomaterials to n-butanol and other gases were investigated.Different concentrations of MWCNTs composite NaBi?MoO₄?₂ nanometer gas sensitive materials research results show that 1wt%NaBi?MoO₄?₂/MWCNT best working temperature from 370?to 260?.At the optimum operating temperature,the sensitivity to 100 ppm n-butanol was 36.3,and the response recovery time was 3-5 s.This is mainly due to the formation of a p-n junction between NaBi?MoO₄?₂ and MWCNT,which significantly improves the gas sensitivity of 1wt%NaBi?MoO₄?₂/MWCNT.Finally,the doping of transition metal ions into pure NaBi?MoO₄?₂powder is studied to explore the influence of transition metal doping on the gas-sensitive performance of the material.To prepare doping directly mixed with different metal ions and different metal ion concentrations,different metal ions such as Ru³⁺,La³⁺,Rh³⁺,Ce³⁺,Y³⁺,Er³⁺,Eu³⁺and Fe³⁺were doped directly.It was found that the doping sensor of La³⁺ion and Fe³⁺ion has a significant improvement on the sensitivity of n-butanol.Gas sensitivity study of different concentrations of Fe³⁺doped NaBi?MoO₄?₂.The sensitivity response?48.2?of the 1 Fe-NBM-200 sensor is best when the doping concentration is 1wt%.Doping the best working temperature is 300°C.Responsive recovery performance is better.Of different concentration of La³⁺doped composite material of gas sensitive analysis,the results show that the optimal doping concentration of 10 wt%,the best working temperature is300?to 100 ppm n-butanol sensitivity of 44.1.