Active and stable copper-based catalyst for CO2 hydrogenation to methanol

Patent metadata

Field	Value
Publication number	US-11878287-B2
Application number	US-202217570655-A
Country	US
Kind code	B2
Filing date	Jan 7, 2022
Priority date	Jan 12, 2021
Publication date	Jan 23, 2024
Grant date	Jan 23, 2024

Abstract

This invention relates to development of novel Cu-based nanocatalysts synthesized via one-pot solution combustion synthesis for CO2 hydrogenation to methanol. The novel Cu-based catalyst has exceptional activity for CO2 hydrogenation with high methanol selectivity in the reaction temperature range between 250° C.-350° C. The novel catalyst also exhibits excellent resilience to deactivation due to sintering.

First claim

What is claimed:

1. A lanthanum oxide-promoted Cu-based nanocomposite catalyst for CO 2 hydrogenation to methanol comprising:
(a) Nanoparticulates in the size range of about 3 nm to 20 nm comprising:
(1) a copper oxide loading of about 20 wt % to 60 wt %;
(2) a zinc oxide loading of about 40 wt % to 65 wt %; and
(3) a lanthanum oxide with a loading of about 0.5 wt % to 10 wt %; and,

(b) Alumina as support; and

wherein the catalyst has a BET surface area of about 77 mg 2 /g.

2. The catalyst of claim 1 , comprising:
(1) a copper oxide loading of about 30% wt % to 60 wt %;
(2) a zinc oxide loading of about 50 wt % to 62 wt %; and
(3) a lanthanum oxide loading between about 0.5 wt % to 10 wt %.

3. The catalyst of claim 1 , wherein the copper oxide loading is about 30 wt %.

4. The catalyst of claim 1 , wherein the zinc oxide loading is about 50 wt %.

5. The catalyst of claim 1 , wherein the lanthanum oxide loading is about 0.5 wt % to 5 wt %.

6. The catalyst of claim 1 , wherein the lanthanum oxide loading is about 1 wt %.

7. The catalyst of claim 1 , wherein the catalyst exhibits a MeOH yield of about 2.5 g MeoH g cat −1 h −1 under the conditions of 1) a temperature of about 325° C.; 2) a pressure of about 85 bars; 3) a H 2 :CO 2 ratio of about 3:1 to 4:1; and, 4) a gas hourly space velocity of between about 7,000 and 55,000 h −1 .

8. The catalyst of claim 7 , wherein the H 2 :CO 2 ratio is about 4:1.

9. The catalyst of claim 7 , wherein the gas hourly space velocity is between about 27,000 and 55,000 h −1 .

10. The catalyst of claim 7 , wherein the catalyst exhibits a MeOH selectivity of about 42 wt %.

11. The catalyst of claim 7 , wherein the catalyst exhibits a CO 2 conversion of about 30%.

12. The catalyst of claim 1 , wherein the catalyst exhibits Cu 2+ -induced phases of about 18% as measured by XPS, wherein the percentage of the induced phases is calculated based on total area of the integrated peaks.

13. A method for the synthesis of the nanocomposite catalyst of claim 1 , wherein the synthesis is a single-step solution combustion synthesis.

14. The method of claim 13 , wherein copper oxide is loaded on the alumina in the range of 30-60 wt %.

15. The method of claim 13 , wherein zinc oxide is loaded on the alumina in the range of 50 wt % to 62 wt %.

16. The method of claim 13 , wherein lanthanum oxide is loaded on the alumina in the range of 0.5 wt % to 3 wt %.

17. The method of claim 13 , wherein about 1 wt % of lanthanum oxide is loaded on the alumina.

18. The method of claim 13 , wherein the single-step solution combustion synthesis comprises the steps:
1) dissolving metal precursor nitrates in water and adding glycine to obtain a mixture wherein the nitrates are copper nitrate trihydrate (Cu(NO 3 ) 2 ·3H 2 O), zinc nitrate hexahydrate (Zn(NO 3 ) 2 ·6H 2 O), aluminum nitrate nonahydrate (Al(NO 3 ) 3 ·9H 2 O), and lanthanum nitrate hexahydrate (La(NO 3 ) 3 ·6H 2 O);
2) stirring the mixture to form a homogeneous mixture and heating the homogeneous mixture over a hot plate for combustion to obtain nanocomposites;
3) calcining the nanocomposites to remove uncombusted metal precursor nitrates in air in a muffle furnace to obtain the nanocomposite catalyst; and
4) activating/reducing the nanocomposite catalyst by passing pure hydrogen stream over the nanocomposite catalyst.

19. The method of claim 18 , wherein the glycine:metal precursor nitrates ratio is in the range of about 0.2:1 to 1.2:1.

20. The method of claim 18 , wherein calcining the nanocomposites is performed at a temperature between about 400° C. to 800° C.

21. The method of claim 18 , wherein the nanocomposite catalyst in step 4) comprises nanoparticles with a size of 6.4 nm.

22. The method of claim 18 , wherein the nanocomposite catalyst in step 4) exhibits more oxygen vacancies and/or surface defects compared to a nanocomposite catalyst that does not comprise lanthanum oxide.

23. The method of claim 22 , wherein the nanocomposite catalyst in step 4) exhibits Cu 2+ -induced phases of about 18% as measured by XPS, wherein the percentage of the induced phases is calculated based on total area of the integrated peaks.

24. The method of claim 18 , wherein step 4) is conducted between about 350° C. to 500° C.

Assignees

• Univ Qatar

Inventors

• Ali Sardar
• Kumar Dharmesh
• El-Naas Muftah

Classifications

• B01J2235/15

  X-ray diffraction · CPC title

• B01J35/45

  Nanoparticles · CPC title

• B01J35/393

  Metal or metal oxide crystallite size · CPC title

• B01J2235/30

  Scanning electron microscopy; Transmission electron microscopy · CPC title

• B01J2235/00

  Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties · CPC title