Process for preparing a monolith with multimodal porosity

Patent metadata

Field	Value
Publication number	US-2021101134-A1
Application number	US-201816608342-A
Country	US
Kind code	A1
Filing date	Apr 23, 2018
Priority date	Apr 28, 2017
Publication date	Apr 8, 2021
Grant date	—

Abstract

Process for preparing a porous monolith comprising between 10% and 100% by weight of a semiconductor relative to the total weight of the porous monolith, which process comprises the following steps:
a) a first aqueous suspension containing polymer particles is prepared; b) a second aqueous suspension containing particles of least one inorganic semiconductor is prepared; c) the two aqueous suspensions prepared in steps a) and b) are mixed in order to obtain a paste; d) a heat treatment of the paste obtained in step c) is carried out in order to obtain the monolith with multimodal porosity.

First claim

1 . A process for preparing a porous monolith comprising between 10% and 100% by weight of a semiconductor relative to the total weight of the porous monolith, and comprising a mesoporous volume, the pore diameter of which is between 0.2 and 50 nm, of between 0.05 and 1 ml/g, and a macroporous volume, the pore diameter of which is greater than 50 nm and less than or equal to 5000 nm, of between 0.01 and 1 ml/g, which process comprises the following steps:
a) a first aqueous suspension containing polymer particles is prepared; b) a second aqueous suspension containing particles of least one inorganic semiconductor is prepared; c) the two aqueous suspensions prepared in steps a) and b) are mixed in order to obtain a paste; d) a heat treatment of the paste obtained in step c) is carried out in order to obtain said porous monolith, said heat treatment being carried out under air at a temperature of between 300 and 1000° C. for 1 to 72 h.

2 . The process as claimed in claim 1 , wherein a heat treatment under air of the paste obtained in step c) is carried out by carrying out three temperature plateaus, a first plateau carried out at a temperature of between 70 and 130° C. for 1 to 12 h, and a second plateau carried out at a temperature of between 130° C. and 220° C. for 1 to 12 h, and a third plateau carried out at a temperature of between 250 and 700° C. for 1 to 12 h.

3 . The process as claimed in claim 1 , wherein the aqueous suspension obtained in step a) contains between 20 and 500 g/l of polymer particles.

4 . The process as claimed in claim 1 , wherein the aqueous suspension obtained in step b) contain between 200 and 900 g/l of semiconductor particles.

5 . The process as claimed in claim 1 , wherein, in step c), the weight ratio between the first aqueous suspension containing the polymer particles and the second aqueous suspension containing the semiconductor particles is between 0.05 and 1.

6 . The process as claimed in claim 1 , characterized in that the polymer particles are in the form of spheres with a diameter of between 0.1 and 5 μm.

7 . The process as claimed in claim 1 , characterized in that the polymer particles are made of polystyrene.

8 . The process as claimed in claim 7 , wherein the polystyrene polymer particles are prepared according to the following steps:
i) a solution of ethanol and polyvinylpyrrolidone (PVP) is prepared, which solution is degassed under a nitrogen stream for at least one hour, the weight ratio of ethanol to PVP being between 50 and 200; ii) the solution is heated to a temperature of between 50 and 90° C.; iii) a reactive mixture of styrene and of a polymerization initiator is prepared, which mixture is degassed under nitrogen for at least one hour, the weight ratio of styrene to initiator being between 30 and 300; iv) the reactive mixture obtained in step iii) is added to the solution obtained in step ii) at a temperature of between 50 and 90° C., and the mixture obtained is stirred at a temperature of between 50 and 90° C. for 1 hour to 48 hours; v) the suspension obtained in step iv) is washed at least twice with water; vi) the polymer particles are recovered by filtration or centrifugation.

9 . The process as claimed in claim 1 , wherein the inorganic semiconductor is in the form of a powder.

10 . The process as claimed in claim 9 , characterized in that the inorganic semiconductor powder comprises particles with a diameter of between 5 and 200 nm.

11 . The process as claimed in claim 1 , wherein the semiconductor is a metal oxide.

12 . The process as claimed in claim 11 , wherein the metal of the inorganic semiconductor is chosen from one or more elements of groups IB, IIB, IVA, VA, VIA, IVB, VB, VIB, VIIIB or IIIA.

13 . The process as claimed in claim 12 , wherein the semiconductor is chosen from Fe 2 O 3 , SnO, SnO 2 , TiO 2 , CoO, NiO, ZnO, Cu 2 O, CuO, Ce 2 O 3 , CeO 2 , In 2 O 3 , WO 3 , V 2 O 5 alone or as a mixture.

14 . The process as claimed in claim 1 , wherein the semiconductor is doped with one or more elements chosen from metal elements, such as for example elements V, Ni, Cr, Mo, Fe, Sn, Mn, Co, Re, Nb, Sb, La, Ce, Ta or Ti, non-metal elements, such as for example C, N, S, F or P, or by a mixture of metal and non-metal elements.

Assignees

• Ifp Energies Now

Inventors

• Bernadet Sophie
• Fecant Antoine
• Uzio Denis
• Backov Renal-Vasco
• Ravaine Serge

Classifications

• B01J35/45

  Nanoparticles · CPC title

• B01J35/51

  Spheres · CPC title

• C04B2235/6567

  Treatment time · CPC title

• C04B2235/3275

  Cobalt oxides, cobaltates or cobaltites or oxide forming salts thereof, e.g. bismuth cobaltate, zinc cobaltite · CPC title

• C04B2235/3239

  Vanadium oxides, vanadates or oxide forming salts thereof, e.g. magnesium vanadate · CPC title