Synthesis and Enhanced Acetone-sensing Properties of Ordered Large-pore Mesoporous Nickel Oxides with Ultrathin Crystalline Frameworks

Acetone is a tracer for monitoring air quality and a potential breath maker for diabetes. It remains a great challenge for current portable sensors to sensitively and selectively detect acetone at low-ppb (part per billion) level. Herein, we present an ordered mesoporous nickel oxide (NiO) with both large mesopores and ultrathin crystalline frameworks for the detection of low-ppb acetone. The ordered mesoporous NiO replicas with predominant large mesopores of 11 nm, high specific surface areas of 121-128 m2/g and ultrathin crystalline frameworks of 5 nm were synthesized by the nanocasting method and the crystalline properties of NiO frameworks were adjusted by changing the annealing temperature from 300 degrees C to 750 degrees C, which resulted in different contents of oxygen deficient on the surface of ultrathin frameworks. The gas-sensing properties for all the NiO samples were investigated and the ordered large-pore mesoporous NiO (NiO-600) with maximum oxygen deficient obtained at 600 degrees C exhibited the highest response (Rgas/Rair-1=2.9) toward acetone (1 ppm, ppm: part per million), which is 3.4 and 30 times larger than those for common mesoporous NiO obtained at 300 degrees C and bulk NiO. Notably, a low detection limit (2 ppb), good selectivity and cycling stability were also observed in NiO-600.