Bismuth Molybdate Nanorods Derived from a Metal-Organic Framework for Triethylamine Gas Sensors

A heterojunction metal oxide semiconductor made of threephasesof bismuth molybdate (BMO) (& alpha;, & beta;, & gamma;) was synthesizedby a one-pot process from a metal-organic framework (MOF) andevaluated in a side-heated sensor for the detection of the toxic gastriethylamine (TEA). An X-ray diffraction analysis indicated thatthe heterostructure comprises 24.1% & alpha;-Bi2Mo3O12, 59.1% & beta;-Bi2Mo2O9, and 16.8% & gamma;-Bi2MoO6. Because of thecollapse of the MOF structure during the synthesis process, BMO nanorodsexhibited surface defects beneficial for gas sensing. Consequently,the TEA sensing performance of & alpha;& beta;& gamma;-BMOMOF was significantly superior to & alpha;& beta;& gamma;-BMO preparedinstead with uncoordinated bismuth nitrate. When compared to single-phase & alpha;-Bi2Mo3O12 (MOF) and & gamma;-Bi2MoO6 (MOF) sensors, the & alpha;& beta;& gamma;-BMOMOF heterojunction sensor exhibited high performance with alimit of detection of 0.5 ppm and a response value of 58.5 to 100ppm TEA at an optimal temperature of 340 & DEG;C. In addition, & alpha;& beta;& gamma;-BMOMOF nanorods exhibited excellent selectivity, long-term stability,and short response and recovery times of 2 and 5 s, respectively.Because of heterojunctions between the different phases, the & alpha;& beta;& gamma;-BMOMOF sensor had a higher electrical resistance in air and adsorbeda larger quantity of oxygen anions capable of reacting with TEA. Thesefeatures of the heterostructure material explain its superior TEAsensing performance. The low-cost and low-toxicity & alpha;& beta;& gamma;-BMOMOF sensor described here is a promising alternative for thedetection of volatile organic molecules.

Automated summary

A heterojunction metal oxide semiconductor, consisting of three phases of bismuth molybdate (BMO) α, β, γ, was synthesized from a metal-organic framework (MOF) through a one-pot process. This heterostructure showed superior sensing performance for the detection of the toxic gas triethylamine (TEA) compared to BMO prepared with uncoordinated bismuth nitrate. The αβγ-BMO-MOF heterojunction sensor exhibited high performance with a limit of detection of 0.5 ppm and a response value of 58.5 to 100 ppm TEA at an optimal temperature of 340°C. The sensor also demonstrated excellent selectivity, long-term stability, and short response and recovery times. The features of the heterostructure material, including higher electrical resistance and adsorption of oxygen anions, explained its superior TEA sensing performance.