The Effect And Research Of Heterojunction And Doping On The Gas Sensing Performance Of NiO-Based Gas Sensor

With the increasing awareness of environmental protection and personal safety,effective detection of the emission of volatile organic components(VOCs)in the air is crucial.In order to meet the increasing demands of social development,preparation of gas sensing materials with high-sensitivity and high-selectivity serve as the main goal in this work.We synthesized the nano-NiO materials with good gas-sensing performance.Furthermore,in order to solve the shortcomings of low sensitivity and poor selectivity of current domestic P-type semiconductor gas sensors,we optimized the gas sensing performance by format nanoscale heterojunction and aliovalent doping.The specific research contents are as follows:Pure phase NiO and different ratio of NiO/ZrO2 nanocomposites with three-dimensional ordered macropororous structure were prepared by a colloidal crystal template method.The gas-sensing performance test demonstrate that all of the prepared materials obtain the best response to xylene.Also,the best ratio of NiO/ZrO2 nanocomposite material shows the best response to of 25.6 to100 ppm xylene at 330 ?,which is nearly ten times than pure phase NiO.Meanwhile,the gas selectivity is also enhanced 1.8-1 1.4 times;and this nanocomposites material exhibits the excellent long-term stability and great anti-humidity performance.The synergistic catalytic effect and modulation of the charge conduction mode caused by the formation of nanoscale heterojunctions are considered the main reason for the enhanced gas sensing performance.Furthermore,Pure phase NiO and Nb-doped NiO with different dope contents nanosheets have been prepared by a one-step hydrothermal method.The gas sensing test shows that:this material has an ultra-high response of 335.1 to 100 ppm xylene at 370 ?under the optimal doping ratio of Nb elemental.Compared with the pure phase material,the gas sensitivity has improved nearly 110 times and the gas selectivity has been improved by 2.1-16.1 times.Furthermore,this gas sensing material obtains an ultra-low theoretical detection limit of 2 ppb.The main reason for the improvement of gas sensing performance is due to the electron sensitization caused by Nb-doping and the higher specific surface area.