1 Introduction In recent years, coatings by ionic liquids (IL) have emerged as a novel approach to improve heterogeneous catalysts.[1-3] ILs are salts with melting points below 100 °C and negligible vapor pressure.[2, 4] A promising application of ILs are solid catalysts with ionic liquid layers (SCILL).[3, 5-15] In these applications, conventional supported catalysts are coated with thin IL films.[1, 2] These IL films can significantly improve the catalytic characteristics, such as the...