| NO_x, especially NO, can cause respiratory disease and bring serious damage to theenvironment. Therefore, It is very significant to prepare NO_xsensors with highsensitivity and fast response at room temperature. In this paper, we synthesized boroncarbon nitride nanotubes (BCNNTs) by chemical vapor deposition (CVD) to developNO_xgas-sensors at room temperature, and then combined the BCNNTs and MWCNTsto prepare BCNNTs(MWCNTs)/ZnO composite materials. The NO_xresponse propertieswere investigated at room temperature by static state injection method, and theirresponse mechanism was discussed.BCNNTs were prepared by two-step method. In the first step, three kinds ofnitrogen-doped carbon nanotubes were synthesized using acetonitrile, urea, melamine.Then carbon nanotubes and nitrogen-doped carbon nanotubes were doped with boron.The relationship of content between nitrogen-doped in first step and boron-doped insecond step were studied. Then the NO_xsensor properties of BCNNTs were test, and theinfluence of boron and nitrogen content to sensor propertie were investigated.The MWCNTs/ZnO composite were synthesized by homogeneous precipitationmethod, then the structure and performance of the composite were characterized andanalysed in detail. The experiment results showed that, the active sites of the materialwere improved and combining carbon nanotubes with zinc oxide became closer byadding polyethylene (PEI). The NO_xresponse properties of sensor have been enhanced.PEI-modificative MWCNTs/ZnO composite were excellent sensitive materials at roomtemperature.Based on BCNNTs, combined with ZnO, BCNNTs/ZnO composite weresynthesized by sol-gel method. The NO_xsensor response with different rates ofBCNNTs/ZnO composite structures was studied. The results showed that adding a goodamount of ZnO could improve response of BCNNTs to NO_x. The proportion ofBCNNTs and zinc acetate at1:6-1:4has the highest sensitivity of13.8%, the responsetime of23s, and high selectivity for NO_x. |
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