Methods for forming compositions including carbide-containing nanorods and/or oxycarbide-containing nanorods and/or carbon nanotubes bearing carbides and oxycarbides. Rigid porous structures including oxycarbide-containing nanorods and/or carbide containing nanorods and/or carbon nanotubes bearing modified carbides and oxycarbides and methods of making the same are also provided. The compositions and rigid porous structures of the invention can be used either as catalyst and/or catalyst supports in fluid phase catalytic chemical reactions. Processes for making supported catalyst for selected fluid phase catalytic reactions are also provided.