Amorphous silicon nitrides were prepared by gas phase ammonolysis of tetrachlorosilane followed by thermal treatment in nitrogen or ammonia atmosphere. After deposition of platinum on the materials the obtained catalysts proved to be catalytically active and selective for propane dehydrogenation. Incorporation of boron, carbon and titanium in the supports influences significantly the catalytic properties. It is suggested that the comparable high catalytic activity, propene selectivity and stability of the catalysts are due to the basic properties of the catalyst surface.