The present invention is directed to ex situ phosphorus-activated crystalline porous silicates such as layered silicates and microporous silicates, processes for said ex situ phosphorus activation, catalyst compositions containing said ex situ phosphorus-activated crystalline porous silicates, and catalyst additives containing said phosphorus-activated crystalline porous silicates. The quintessence of the invention is that the crystalline porous silicate is ex situ activated with a phosphorus-containing compound in the solid state. The activation method is universally applicable and is more economical and more environmentally friendly than the known phosphorus activation methods, because the drying step necessary in the prior art methods can be avoided.