Аңдатпа
Ceramic pellets of pure ZnGa 2 O 4 and ZnGa 2 O 4 with Er-addition are synthesized and their structural and gas-sensitive properties are investigated. The addition of Er leads to the formation of a second Er 3 Ga 5 O 12 phase in the ZnGa 2 O 4 matrix and a larger active surface which allows an 11.1-fold increase in the response of ZnGa 2 O 4 to 10 4 ppm of CH 4 . At the maximum response temperature corresponding to 650 ºC, the responses to 100 and 10 4 ppm of CH 4 for ZnGa 2 O 4 with Er addition were 2.91 a.u. and 20.74 a.u., respectively. ZnGa 2 O 4 with Er addition is characterized by a wide dynamic range of CH 4 concentrations, from 100 ppm to 20000 ppm, weak dependence of gas-sensitive characteristics on humidity in the relative humidity range of 30–70%, weak changes of gas-sensitive characteristics under cyclic gas exposure. The samples also demonstrate high responses to NO 2 and H 2 , which at a gas concentration of 100 ppm and a temperature of 650 °C are 3.37 a.u. and 4.77 a.u., respectively. A plausible mechanism of the sensing effect of ZnGa 2 O 4 with Er addition is proposed and prospects for the development of high-temperature CH 4 sensors based on the studied samples for combustion monitoring systems and determination of the ideal fuel/air mixture are discussed. • Ceramic plates of pure ZnGa 2 O 4 and ZnGa 2 O 4 with Er addition were synthesized. • Addition of Er allows an 11.1-fold increase in response of ZnGa 2 O 4 to CH 4 . • The responses of ZnGa 2 O 4 with Er to 100 and 10 4 ppm of CH 4 at 650 ºC were 2.91 and 20.74. • The material synthesized exhibited high responses to NO 2 and H 2 . • Prospects for development of high-temperature CH 4 sensors for combustion monitoring systems are discussed. • Er addition acts as catalyst and leads to formation of a larger active surface.