Structural distinctions of Fe2O3–In2O3 composites obtained by various sol–gel procedures, and their gas-sensing features

New and various approaches to the sol–gel synthesis of advanced gas-sensing materials based on nanosized Fe2O3–In2O3 (9:1 mol) mixed oxides, which differ in phase composition and grain size, have been considered in this paper. The correlation between the structural features of the composites and their gas-sensing behavior has been established. It was found that multi-phase Fe2O3–In2O3 composites containing metastable γ-Fe2O3 structure are characterized by the greatest sensitivity to both reducing (C2H5OH) and oxidizing (NO2) gases tested in this paper. The influence of synthesis conditions on the structural peculiarities of the Fe2O3–In2O3 composites was studied in detail and the possibility to adjust fine structure of the materials was demonstrated.