non - spherical siliceous particles having a plurality of porous branches are disclosed and claimed . the porous branches are randomly oriented and elongated , ring - like , and / or aggregated . an additive introduced during synthesis of the particles modifies pore volume and morphology . the tunability of the pore volume includes an inner diameter ranging from about 2 å to about 50 , 000 å . synthesizing the particles includes mixing under constant or intermittent stirring in a reaction vessel an aqueous silicic acid solution with an acidic heel solution to form a mixture . the stirring may optionally be performed at a variable speed . an additive is introduced into the mixture at a controlled rate , wherein the additive imposes a ph change from a lower ph to a higher ph to the mixture to induce siliceous particle precipitation . optionally , a metal dopand may be introduced into the particles and / or at least a portion of an outer surface located outside of the pores and / or an inner surface located inside of the pores may be modified .