Abstract: The invention relates to a method for forming a transparent conductive thin film of In2O3—SnO2 on a surface of a plastics substrate of less heat resistance other than that of glass, ceramics, etc. When an In2O3—SnO2 precursor sol is produced by hydrolyzing and polymerizing a solution containing indium alkoxide and tin alkoxide, either tri-s-butoxyindium or tri-t-butoxyindium is used as the indium alkoxide. Water is added to the solution containing indium alkoxide and tin alkoxide at a temperature of not higher than −20° C.

Abstract: A catalyst for exhaust gas purification, comprising a heat-resistant inorganic monolith carrier and a catalyst layer loaded thereon, the catalyst layer including a catalyst composition containing at least one noble metal selected from Pt, Pd and Rh, as an active catalyst component, and active alumina. The catalyst composition has a specific surface area of at least 50 m.sup.2 /g and a porosity of at least 50%. This catalyst for exhaust gas purification contains noble metal(s) in a well dispersed state, has excellent high-temperature durability, and is low in thermal deterioration of catalyst performance. Hence, the catalyst can be suitably used as a converter installed in engine manifolds of gasoline engine automobiles, or as a heater having improved purification ability for the exhaust gases emitted from automobiles during their cold start.