Synthesis of hollow spherical nickel oxide and its gas‐sensing properties

Abstract Semiconductor metal oxides have attracted wide attention in the area of gas sensor due to that they have unique advantages in the rapid and accurate detection of harmful gases. A simple strategy is to synthesize porous NiO hollow microspheres via a simple hydrothermal method with trisodium citrate as structure guide agent is presented in this paper, and the shell of the microsphere is composed of porous and lamellar assembly units. The cavity proportion can be adjusted by changing the amount of trisodium citrate. A reasonable mechanism was proposed to explain the formation of porous NiO hollow microspheres. As a gas‐sensing material, porous NiO hollow microspheres show excellent gas selectivity and rapid response recovery time for n‐butyl alcohol gas. When the content of trisodium citrate was 0.10 g, the synthesized hollow sphere NiO had the highest response value (25.6) to 100 × 10 –6 of n‐butyl alcohol at 300 °C and the response and recovery times were only 68 and 10 s.