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

Abstract In this work, highly crystalline mesoporous In 2 O 3 nanowires (NWs) doped with K 2 O, ZnCl 2 or CaCl 2 were synthesized by template-calcined method using SBA-16 as template. The mesoporous K 2 O-In 2 O 3 NWs (INW-K2), which was synthesized by mixing 0.2 mol L −1 In(NO 3 ) 3 solution with 0.02 g KNO 3 so that In(NO 3 ) 3 and KNO 3 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-K2, K 2 O doped on its surfaces serves as alkaline center and benefits the adsorption and diffusion of acidic NO x . 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 NO x to 97 ppm 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 K 2 O-In 2 O 3 nanowires might offer a new opportunity for synthesizing multifunctional sensing materials in future.