| abstract |
Provided is a highly stable gas sensor capable of detecting carbon dioxide. Provided are: a carbon dioxide gas sensor provided with an insulating substrate 3 and a gas-sensing layer 1 formed on one principal surface of the insulating substrate 3 via an electrode 2, the gas sensor wherein the gas-sensing layer 1 includes (a) one or more rare earth metal oxycarbonates represented by the formula Ln2O2CO3 (where Ln is one or more rare earth metal elements selected from Sc, Y, La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Pr, Yb, and Lu), the main component of the rare earth metal oxycarbonate being a hexagonal crystal rare earth metal oxycarbonate, or includes (b) a monoclinic crystal samarium dioxycarbonate; a method for manufacturing a gas sensor; and a method for selectively manufacturing a crystal polymorphism of a lanthanum dioxycarbonate represented by the formula La2O2CO3. |