4. Conclusion
A novel nanocomposite material, Ni0.9Zn0.1O/ZnO, has beensuccessfully obtained via the thermal decomposition of mixed pre-cursor compound synthesized using a facile coprecipitation routeand its gas sensing properties investigated for many gases (CO, H2and NO2). According to the XRD results the nanocomposite materi-als were a homogeneous mixture of Ni0.9Zn0.1O and ZnO, excludingthe possibility of the simple NiO/ZnO nanocomposite. Enhancedsensing properties with respect to CO were observed by compar-ison with those of pure Ni0.9Zn0.1O and ZnO structures and theoptimal operating temperature was found to be 300◦C. It was alsofound that the as synthesized composite material can be used atlower operating temperature (225◦C) as selective NO2gas sen-sor. The humidity has no significant influence on the response ofsensor beyond 20%. The heterojunction between Ni0.9Zn0.1O andZnO and their catalytic activities are probably the principal factor responsible for the enhanced gas sensing performance of the com-posite material.