Synthesis of mesoporous K2O-In2O3 nanowires and NOx gas sensitive performance study in room temperature

In this work, highly crystalline mesoporous In2O3 nanowires (NWs) doped with K2O, ZnCl2 or CaCl2 were synthesized by template-calcined method using SBA-16 as template. The mesoporous K2O-In(2)O(3)NWs (INW-K2), which was synthesized by mixing 0.2 mol In(NO3)(3) solution with 0.02 g KNO3 so that In(NO3)(3) and KNO3 mass ratio was 30:1, has high density of chemisorbed oxygen. Its diameter is about 4-8 nm and pore size is 3-5 nm. For INW-K-2, K2O doped on its surfaces serves as alkaline center and benefits the adsorption and diffusion of acidic NOx. Meanwhile, the INW-K2 provides large number of active centers for gaseous reactions on the surface of the nanowires. Therefore, the gas sensing property of INW-K2 is significantly improved, the response of NOx to 97 pPin is about 151.78 and response time is only 12 s, the detection limitation decreased to 48.5 ppb at room temperature (RT). The highly crystalline mesoporous K2O-In2O3 nanowires might offer a new opportunity for synthesizing multifunctional sensing materials in future. (C) 2016 Elsevier Inc. All rights reserved.