Synthesis Of BiVO₄ Nanocomposites And Their Gas Sensitive Properties And Mechanisms For Triethylamine

With the continuous improvement of the living standards,people have put forward higher requirements for the quality of the air environment of living condition.Some organic volatile compounds(VOCs)produced from daily production have a bad effect on the physical health and ambient air.Triethylamine(TEA)as one of VOCs gases,is an important industrial raw material and can be volatilized into an extremely toxic gas which can cause great damage to human health.Too much exposure to TEA can cause skin burns,headaches,nausea,and even death.In addition,TEA can be produced by microorganisms degrading dead fish and seafood.Therefore,the development of new sensors that quickly and selectively respond to TEA is crucial for biomedicine,the food industry and our daily life.This work studied the gas sensing performance of the metal oxide semiconductors based composites to TEA by doping of metal elements,rGO decoration and constructing heterojunction methods,the studied contents as follows:1.A novel rGO-modified W-doped BiVO4 sensing material was synthesized by metal organic decomposition and hydrothermal treatment to detect TEA gas.The structure,morphology and sensing properties of the samples were characterized and measured by spectroscopy and gas sensing systems.The results showed that the response of the 6W-BiVO4/rGO5 composite based sensor to TEA is 12.8,and the response time is 16 s,which is 5.12 times and 2.75 times that of BiVO4,respectively.In addition,the sensor exhibited excellent selectivity and stability to 20 ppm TEA at optimum temperature of 135?.This increase in gas sensitivity was attributed to the increased electron concentration of BiVO4 due to the doping of W element as an electron donor.Further modification of rGO resulted in the increase of specific surface area,surface defects and electron transfer rate for the composite.2.In this paper,the nanorods a-MoO3 nanostructures were prepared by hydrothermal method.BiVO4 nanoparticles were modified on the surface of ?-MoO3 by metal organism decomposition method to construct a novel n-n heterojunction of ?-MoO3/BiVO4 composite and apply in the detection of TEA gas.The structure and morphology of the material were characterized and the sensing properties to TEA were also examined.The results showed that the response of ?-MoO3/BiVO4 composite to 20 ppm TEA was 1.86 times and 15 times that of ?-MoO3 and BiVO4,respectively at 125?.The enhanced sensing characteristics can be attributed to that the formation of electron depletion layer at the interface of the n-n heterostructure,which further increases the energy barrier and sensitivity of the composite.