Co ₃ O ₄ / PEI-CNTs Controllable Preparation And Gas Sensing Properties Of Composites

It is well known that CO is poisonous gases and air pollutants, bring seriousdamage to the environment. Therefore, it is very significant to prepare CO sensors withhigh sensitivity and fast response at room temperature. The cobalt oxide (Co3O4) withits unique performance has been widely applied in the field of gas sensitive sensor. Inthis researd, Co3O4/PEI-CNTs composite materials were sythesised. Bypolyethyleneimine (PEI) modification of carbon nanotubes (MWCNTs) as the carrier,with air as oxidant, supported cobalt oxide on the carrier by hydrothermal method. Thegas sensing properties of Co3O4/PEI-CNTs on CO were investigated at roomtemperature by static state injection method, and their response mechanism wasdiscussed.First, changing of hydrothermal synthesis temperature under the certain time, thepreparation of the different temperature of Co3O4/PEI-CNTs composites. Second underoptimum temperature，the change of hydrothermal synthesis，preparation of differenttime of Co3O4/PEI-CNTs composites. We detected the gas sensing property ofCo3O4/PEI-CNTs on CO at room temperature. And the sensing mechanism wasdiscussed in two aspects:1) Unique one-dimensional composite structure and finegrain can connection and interaction between the electron is easy to transport, in thecobalt oxide free diffusion between particles and carbon nanotubes. As a result, thesmall Co3O4nanoparticles on the surface of the PEI-CNTs the excellent properties ofthe CO gas sensor is very important;2) A one-dimensional Co3O4/PEI-CNTs havehigh specific surface, can be used as a gas adsorption-echoing off diffusion channel.For CO adsorption on the surface and the reaction of oxygen ion provides more activesite, conducive to its reaction with CO at room temperature. The results show that thesynthesis of Co3O4/PEI-CNTs composites at room temperature was synthesized bymeans of CO gas sensor has good response. In summary, with porous structure Co3O4/PEI-CNTs composite materials sensor,not only high sensitivity, fast response rapidly, and has good selectivity and relativelylong stability, there will be a very good application prospect in the field of sensor.