Production of a porous product including post adapting a pore structure

A production process for making a porous silicon dioxide material comprising:

• a. feeding a feed material composition into a reaction zone at a feeding position, wherein the feed material composition is liquid or gaseous or both;
• b. reacting the feed material composition in the reaction zone into a first plurality of particles by a chemical reaction;
• c. depositing the first plurality of particles onto a substrate surface of a substrate, thereby obtaining a porous silicon dioxide material, having a pore structure, in the form of up to 20 layers superimposing the substrate surface;
• d. at least partially removing the porous silicon dioxide material from the substrate surface;
• and
• e. modifying the pore structure of the porous silicon dioxide material, thereby obtaining the porous silicon dioxide material having a further pore structure, wherein modifying the pore structure comprises a thermal treatment of the porous silicon dioxide material and;
• wherein the thermal treatment satisfies at least one of the following:
• a. the maximum temperature in the thermal treatment is higher than the maximum temperature of the substrate surface reached in a) to e);
• b. the thermal treatment comprises:
• i. increasing the temperature of the porous silicon dioxide material to a temperature in the range from 1100 to 1400° C.,
• ii. holding the temperature of the porous silicon dioxide material at a temperature in the range from 1100 to 1400° C. for a duration in the range from 100 to 2000 min, and
• iii. decreasing the temperature of the porous silicon dioxide material below 1000° C.;
• and
• c. the temperature of the removed porous silicon dioxide material is increased at a rate in the range from 2 to 10° C./min in the thermal treatment.