Bifunctional catalyst and method of use for hydrogenation of carbon dioxide to hydrocarbons

1 . A method of hydrogenating carbon dioxide to produce at least one hydrocarbon selected from the group consisting of methane, ethane, propane, and butane, the method comprising contacting an input gas stream containing carbon dioxide (CO 2 ) and hydrogen (H 2 ) gases with a bifunctional catalyst comprising a metal oxide in combination with a redox active ceramic support, wherein the redox active ceramic support comprises the formula BaZr 1-x-y-z M 1 y M 2 z Y x O 3-δ , wherein:

0.1≤x≤0.2, 0≤y≤0.8, 0≤z≤0.8, 0<(x+y+z)<1, and 0≤δ≤0.1, wherein δ represents oxygen-ion vacancy;

M 1 and M 2 are selected from lanthanide elements, except that M 2 may alternatively be a Group 5 transition metal; and

the metal oxide is selected from iron oxides and cobalt oxides and is present in the bifunctional catalyst in an amount of 10-50 wt %.

2 . The method of claim 1 , wherein 0≤y≤0.1, and 0≤z≤0.1.

3 . The method of claim 1 , wherein the redox active ceramic support has the formula BaZr 1-x Y x O 3-δ , wherein 0<x≤0.2.

4 . The method of claim 3 , wherein the redox active ceramic support has the formula BaZr 0.85 Y 0.15 O 3-δ .

5 . The method of claim 1 , wherein M 1 and M 2 are selected from Ce and Yb.

6 . The method of claim 5 , wherein the redox active ceramic support has the formula BaZr 1-x-y-z Ce y Yb z Y x O 3-δ , wherein 0<y≤0.8, 0<z≤0.2, and 0<(x+y+z)<1.

7 . The method of claim 1 , wherein the contacting occurs at a temperature in a range of 250° C. to 450° C.

8 . The method of claim 1 , wherein the contacting occurs at a temperature in a range of 300° C. to 450° C.

9 . The method of claim 1 , wherein the contacting occurs at a temperature in a range of 350° C. to 450° C.

10 . The method of claim 1 , wherein the CO 2 and H 2 gases are present in the contacting step in a CO 2 :H 2 ratio of 1:10-1:1.

11 . The method of claim 1 , wherein the CO 2 and H 2 gases are present in the contacting step in a CO 2 :H 2 ratio of 1:3-1:1.

12 . The method of claim 1 , wherein the CO 2 and H 2 gases are at a pressure of 10-100 atm when contacting the bifunctional catalyst.

13 . The method of claim 1 , wherein the CO 2 and H 2 gases are at a pressure of 20-50 atm when contacting the bifunctional catalyst.

14 . The method of claim 1 , wherein the CO 2 and H 2 gases make contact with the bifunctional catalyst for a gas-phase residence time of 1 second to 2 hours.

15 . The method of claim 1 , wherein bifunctional catalyst contains 0.1-90 wt % of the metal oxide.

16 . The method of claim 1 , wherein the method employs a weight hourly space velocity (WHSV) of CO 2 in a range of 0.2-3 h −1 .

17 . The method of claim 1 , wherein the method employs a weight hourly space velocity (WHSV) of CO 2 in a range of 0.5-2.5 h −1 .

18 . The method of claim 1 , wherein, prior to contacting the input gas stream with the bifunctional catalyst, the method further comprises pretreating the bifunctional catalyst by contacting the bifunctional catalyst with hydrogen gas or hydrogen-inert gas mixture at an elevated temperature of 450-600° C.

19 . The method of claim 18 , wherein the pretreating further comprises carburizing the bifunctional catalyst at an elevated temperature of 450-600° C. in the presence of a hydrocarbon and hydrogen gas.

20 . The method of claim 1 , wherein the bifunctional catalyst is contained in a packed-bed reactor.

21 . The method of claim 1 , wherein said at least one hydrocarbon comprises at least one selected from the group consisting of C 2 H 6 , C 3 H 8 , and C 4 H 10 .

22 . The method of claim 1 , wherein said bifunctional catalyst comprises said metal oxide incorporated into said redox active ceramic support.