The CuO doped SnO₂ nanocrystalline powders were prepared by the Sol-Gel method, which were used to manufacture gas sensors with good gas-sensing characterization. Treatment at different temperature was investigated. The gas sensitive effect on gas had been measured to the powders which had different concentrations. The results show that the prepared nano-sized powders have large specific surface area, high surface activation and  the rational annealing temperature is 650 ℃,SnO₂ gas sensors doped 4%(molar fraction) CuO have high sensitivity and high selectivity especially for greenhouse gas CO₂.  

SnO₂,    ,  Doping,    , CuO,    ,  Gas sensing properties,    , Greenhouse gas CO₂