Herein, we describe a strategy for fabricating ordered mesoporous In2O3-reduced graphene oxide(r GO)nanocomposite through ultrasonic mixing, where ordered mesoporous In2O3 nanoparticles are synthesized via the nanocasting route by using mesoporous silica as a hard template, which possess ordered mesostructure with a large surface area of 81 m2g-1, and r GO nanosheets are synthesized from graphite via graphene oxide(GO) as intermediate. After coupled with r GO, mesoporous In2O3 could maintain its ordered mesostructure. We subsequently investigate the gas-sensing properties of all the In2O3 specimens with or without r GO for different gases. The results exhibit the ordered mesoporous In2O3-r GO nanocomposite possesses significantly enhanced response to ethanol even at low concentration levels, superior over pure mesoporous In2O3 nanoparticles. Similar strategy could be extended to other ordered mesoporous metal oxide–r GO nanocomposite for improving the gas-sensing property.
Highly sensitive and selective detection against specific target gases,especially at low-ppb(part per billion)level,remain a great number of challenges in gas sensor applications.In this paper,we first present an ordered mesoporous NiFe_2O_4 for highly sensitive and selective detection against low-ppb toluene.A series of mesoporous NiFe_2O_4 materials were synthesized by templating from mesoporous silica KIT-6 and its framework thickness was reduced from 8.5 to 5 nm by varying the pore size of KIT-6 from 9.4 to 5.6 nm,accompanied with the increase of the specific surface area from 134 to 216 m^2g^(-1).The ordered mesoporous NiFe_2O_4 with both ultrathin framework of 5 nm and large specific surface area of up to 216 m^2g^(-1)exhibits a highest response(R_(gas)/R_(air)-1=77.3)toward 1,000 ppb toluene at 230℃ and is nearly 7.3 and 76.7 times higher than those for the NiFe_2O_4 replica with thick framework and its bulk counterpart respectively,which also possesses a quite low limit of detection(<2 ppb),and good selectivity.
Xiaoyong LaiKun CaoGuoxin ShenPing XueDan WangFang HuJianli ZhangQingfeng YangXiaozhong Wang
