Superficially porous particles with dual pore structure and methods for making the same

A superficially porous particle, comprising:

• a non-porous inner core;
• and
• a porous outer shell, comprising:
• an inner porous region comprising ordered cylindrical pores substantially perpendicular to the non-porous inner core, wherein the median cylindrical pore diameter is from about 15 to about 1000 Å;
• an outer porous region comprising conical pores which extend to the surface of the particlesand have a median conical pore size of about 150 to about 2500 Å, wherein the conical pores are in fluid communication with the cylindrical pores of the inner porous region;
• and
• wherein the median conical pore size is larger than the median cylindrical pore size.

A method of making superficially porous particles, the method comprising:

• subjecting substantially solid inorganic oxide particles selected from, silica, hybrid material, alumina, zirconia, or titania, in an aqueous solution to agitation for a time and a pH sufficient to pseudomorphically transform said particles, in the presence of a first cationic surfactant and a second anionic surfactant that together form micelles;
• wherein the transformed particles comprise:
• non-porous inner cores;
• and
• porous outer shells, comprising:
• inner porous regions comprising ordered cylindrical pores substantially perpendicular to the non-porous inner cores, wherein the median cylindrical pore diameter is from about 15 to about 1000 Å;
• outer porous regions comprising conical pores which extend to the surface of the particles and have a median conical pore size of about 150 to about 2500 Å, wherein the conical pores are in fluid communication with the cylindrical pores of the inner porous region;
• and
• wherein the median conical pore size is larger than the median cylindrical pore size.