Supported transition metal nanoparticle catalyst and use thereof as a hydrogenation catalyst

1 . A hydrogenation catalyst for an anthraquinone process for production of hydrogen peroxide, the catalyst comprising:

transition metal nanoparticles wherein the transition metal of the nanoparticles is selected from the group consisting of Cu, Ru, Rh, Pd, Ag, Re, Os, Ir, Pt, Au, and alloys of two or more thereof, stabilizing ligands comprising a cationic surfactant, and a support material selected from the group consisting of alumina, silica-alumina, aluminosilicates, and mixtures of two or more thereof,

wherein at least a portion of the stabilizing ligands are adsorbed on the surface of the transition metal nanoparticles so as to form stabilized transition metal nanoparticles,

wherein the stabilized transition metal nanoparticles are impregnated into the support material,

wherein the catalyst displays a molar ratio of the stabilizing ligands to the transition metal in the nanoparticles calculated as the element, wherein the molar ratio is comprised in the range of from 3 to 4.5.

2 . The catalyst according to claim 1 , wherein the number-based average particle size D50 of the transition metal nanoparticles is in the range of from 0.2 to 20 nm.

3 . The catalyst according to claim 1 , wherein the stabilizing ligands form a micelle and/or a liposome around at least a portion of the respective nanoparticles.

4 . The catalyst according to claim 1 , wherein the catalyst comprises from 0.5 to 2.5 wt.-% of transition metal nanoparticles calculated as the transition metal and based on 100 wt.-% of the support material.

5 . The catalyst according to claim 4 , wherein the support material is a particulate material comprising sodium aluminosilicate.

6 . The catalyst according to claim 5 , wherein the support material has a BET surface area in the range of from 140 to 300 m 2 /g, wherein the BET surface area is determined according to ISO 9277:2010.

7 . The catalyst according to claim 1 , wherein the support material is a monolith substrate and/or is in the form of granules.

8 . A process for the preparation of the catalyst of claim 1 comprising transition metal nanoparticles, stabilizing ligands, and a support material, the process comprising:

(1) dissolving one or more surfactants and optionally one or more coordinating agents into a solvent system;

(2) dissolving one or more transition metal salts into a solvent system;

(3) mixing the solution obtained in (1) with the solution obtained in (2);

(4) optionally adjusting the pH of the mixture obtained in (3) to a pH in the range of from 2 to 8;

(5) heating the mixture obtained in (3) or (4) to a temperature in the range of from 50 to 100° C. to form stabilized transition metal nanoparticles;

(6) separating excess surfactant from the mixture obtained in (5);

(7) contacting the mixture obtained in (6) with a support material for supporting the stabilized transition metal nanoparticles on the support material; wherein in the mixture obtained in (6), the molar ratio of the one or more surfactants to the transition metal in the nanoparticles calculated as the element is comprised in the range of from 1 to 7.

9 . The process according to claim 8 , wherein in (6) the molar amount of surfactants in the mixture obtained in (5) is reduced by 20 to 80%.

10 . The process according to claim 8 , wherein in (4) the pH is adjusted to a pH in the range of from 2.5 to 7.5.

11 . A catalyst comprising:

transition metal nanoparticles wherein the transition metal of the nanoparticles is selected from the group consisting of Pd, Ag, Pt, Au, and alloys of two or more thereof; stabilizing ligands comprising a cationic surfactant; and a support material comprising sodium aluminosilicate;

wherein at least a portion of the stabilizing ligands are adsorbed on the surface of the transition metal nanoparticles so as to form stabilized transition metal nanoparticles,

wherein the stabilized transition metal nanoparticles are impregnated into the support material,

wherein the catalyst displays a molar ratio of the stabilizing ligands to the transition metal in the nanoparticles calculated as the element, wherein the molar ratio is comprised in the range of from 0.1 to 25,

wherein the catalyst comprises from 0.5 wt % to 2.5 wt % of transition metal nanoparticles calculated as the transition metal and based on 100 wt % of the support material,

wherein the support material has a BET surface area in the range of from 140 m 2 /g to 300 m 2 /g, wherein the BET surface area is determined according to ISO 9277:2010,

wherein the catalyst is a hydrogenation catalyst for an anthraquinone process for production of hydrogen peroxide.

12 . The catalyst of claim 11 , wherein the stabilized transition metal nanoparticles are impregnated into the support material by incipient wetness impregnation and/or by vacuum impregnation.