1. A method of reducing CO2 to CO, the method comprising:
(a) contacting CO2 with a catalyst, in the presence of H2, wherein the catalyst has plasmonic photocatalytic reductive activity when exposed to radiation having a wavelength between about 380 nm and about 780 nm; and
(b) exposing the catalyst, CO2, and H2 to non-coherent radiation having a wavelength between about 380 nm and about 780 nm such that the catalyst undergoes surface plasmon resonance, wherein the surface plasmon resonance increases the rate of CO2 reduction to CO as compared to the rate of CO2 reduction to CO without surface plasmon resonance in the catalyst.
2. The method of claim 1, comprising, in step (b), exposing the catalyst, CO2, and H2 to solar radiation.
3. The method of claim 1, wherein the catalyst comprises a metallic element have an average particle size no greater than 100 nm in combination with a semiconductor material.
4. The method of claim 3, wherein the metallic element is selected from the group consisting of calcium, copper, europium, gold, lithium, magnesium, palladium, platinum, potassium, silver, sodium, rubidium, and yttrium, and combinations thereof; and wherein the semiconductor material is selected from the group consisting of oxides of titanium, aluminum, iron, silicon, zinc, and cerium, and combinations thereof.
5. The method of claim 3, wherein the metallic element comprises copper, silver, platinum, or gold, and the semiconductor material comprises titania or ceria.
6. The method according to any one of claims 1 to 5, wherein the surface plasmon resonance in the catalyst increases the rate of CO2 reduction to CO by a factor of at least 1.8 as compared to the rate of CO2 reduction to CO in the absence of surface plasmon resonance in the catalyst.
7. The method according to any one of claims 1 to 5, wherein the surface plasmon resonance in the catalyst increases the rate of CO2 reduction to CO by a factor of at least 3 as compared to the rate of CO2 reduction to CO in the absence of surface plasmon resonance in the catalyst.
8. The method according to any one of claims 1 to 5, wherein the surface plasmon resonance in the catalyst increases the rate of CO2 reduction to CO by a factor of at least 4 as compared to the rate of CO2 reduction to CO in the absence of surface plasmon resonance in the catalyst.
9. The method according to any one of claims 1 to 5, wherein the surface plasmon resonance in the catalyst increases the rate of CO2 reduction to CO by a factor of at least 5 as compared to the rate of CO2 reduction to CO in the absence of surface plasmon resonance in the catalyst.
10. A method of reducing CO, to CO, the method comprising:
(a) contacting CO2 with a catalyst, in the presence of H2, wherein the catalyst has plasmonic photocatalytic reductive activity when exposed to non-coherent radiation having a wavelength between about 380 nm and about 780 nm; and
(b) exposing the catalyst, CO2, and H2 to solar radiation such that the catalyst undergoes surface plasmon resonance, wherein the surface plasmon resonance increases the rate of CO2 reduction to CO as compared to the rate of CO2 reduction to CO without surface plasmon resonance in the catalyst.
11. The method of claim 10, wherein upon exposing the catalyst, CO2, and H2 to solar radiation, the catalyst achieves a light efficiency of at least about 2%.
12. The method of claim 10, wherein upon exposing the catalyst, CO2, and H2 to solar radiation, the catalyst achieves a solar light efficiency of at least about 3%.
13. The method of claim 10, wherein upon exposing the catalyst, CO2, and H2 to solar radiation, the catalyst achieves a solar light efficiency of at least about 4%.
14. The method of claim 10, wherein the catalyst comprises a metallic element have an average particle size no greater than 100 nm in combination with a semiconductor material.
15. The method of claim 14, wherein the metallic element is selected from the group consisting calcium, copper, europium, gold, lithium, magnesium, palladium, platinum, potassium, silver, sodium, rubidium, and yttrium, and combinations thereof; and wherein the semiconductor material is selected from the group consisting of oxides of titanium, aluminum, iron, silicon, zinc, and cerium, and combinations thereof.
16. The method of claim 14, wherein the metallic element comprises copper, silver, platinum, or gold, and the semiconductor material comprises titania or ceria.
17. The method according to any one of claims 10 to 16, wherein the surface plasmon resonance in the catalyst increases the rate of CO2 reduction to CO by a factor of at least 1.8 as compared to the rate of CO2 reduction to CO in the absence of surface plasmon resonance in the catalyst.
18. The method according to any one of claims 10 to 16, wherein the surface plasmon resonance in the catalyst increases the rate of CO2 reduction to CO by a factor of at least 3 as compared to the rate of CO2 reduction to CO in the absence of surface plasmon resonance in the catalyst.
19. The method according to any one of claims 10 to 16, wherein the surface plasmon resonance in the catalyst increases the rate of CO2 reduction to CO by a factor of at least 4 as compared to the rate of CO2 reduction to CO in the absence of surface plasmon resonance in the catalyst.
20. The method according to any one of claims 10 to 16, wherein the surface plasmon resonance in the catalyst increases the rate of CO2 reduction to CO by a factor of at least 5 as compared to the rate of CO2 reduction to CO in the absence of surface plasmon resonance in the catalyst.
21. The method of any one of the preceding claims, wherein the method is conducted at a temperature of from about 100\xb0 C. to about 400\xb0 C., wherein H, is present in a greater concentration than CO2, and the H2 and CO2 are present at a pressure of from atmospheric to about 2000 psi.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method of operating an internal combustion engine having a combustion chamber with a piston and a spark plug, comprising:
when transitioning between spark ignition combustion and autoignition combustion, creating a first mixture of air and fuel, adjusting an operating condition of the engine so that said first mixture of air and fuel in the combustion chamber approaches, but does not achieve, the autoignition temperature, and performing a spark from the spark plug so that at least a portion of said first mixture combusts to raise a remaining portion of said first mixture to said autoignition temperature; wherein said spark for said first mixture is performed after top dead center of piston position.
2. The method of claim 1 further comprising, during said transition, performing an injection during a compression stroke so that a second stratified mixture of air and fuel is formed; and performing a spark from the spark plug so that the second mixture combusts.
3. The method of claim 1 wherein said first mixture is created by performing a first injection during an intake stroke so that a lean homogeneous air and fuel region is created, performing a second injection during a compression stroke so that a less lean homogeneous air and fuel region is created substantially near the spark plug.
4. A method of operating an internal combustion engine having a combustion chamber with a piston, an in-cylinder fuel injector, and a spark plug comprising:
during a first mode, performing an injection before a compression stroke to create a first substantially homogenous mixture of fuel and air; and performing a spark from a spark plug so that the first mixture combusts;
during a second mode, performing an injection during a compression stroke to create a second mixture of stratified air and fuel; and performing a spark from the spark plug so that the second mixture combusts;
during a third mode, creating a third air and fuel mixture by performing a first injection during an intake stroke so that a lean homogeneous air and fuel region is created and performing a second injection during a compression stroke so that a less lean homogeneous air and fuel region is created substantially near the spark plug; adjusting an operating condition of the engine so that said third mixture of air and fuel in the combustion chamber approaches, but does not achieve, the autoignition temperature; and performing a spark from the spark plug after top dead center of piston position so that the third mixture combusts; and
during a fourth mode, adjusting an operating condition of the engine so that a fourth mixture of air and fuel in the combustion chamber attains an autoignition temperature and combusts without requiring a spark from the spark plug.
5. The method of claim 4, wherein the first mode is used during a period of higher engine load than said fourth mode.
6. The method of claim 4, wherein the first mode is used during an engine warm up period.
7. The method of claim 4, wherein the second mode is used for at least one cycle during a transition between the first mode and the fourth mode.
8. The method of claim 4, wherein the third mode is used for at least one cycle during a transition between the first mode and the fourth mode.
9. The method of claim 4, wherein the second mode is used for at least one cycle and then the third mode is used for at least one cycle during a transition from the first mode to the fourth mode.
10. The method of claim 4, wherein the third mode is used for at least one cycle and then the second mode is used for at least one cycle during a transition from the fourth mode to the first mode.
11. A method of operating an internal combustion engine having a combustion chamber with a piston, an in-cylinder fuel injector, and a spark plug comprising:
during a first transition between operating modes, creating a first mixture of air and fuel by performing a first injection during an intake stroke so that a lean homogeneous air and fuel region is created, performing a second injection during a compression stroke so that a less lean homogeneous air and fuel region is created substantially near the spark plug, and adjusting an operating condition of the engine so that said first mixture of air and fuel in the combustion chamber approaches, but does not achieve, the autoignition temperature; and performing a spark from the spark plug after top dead center of piston position so that at least a portion of said first mixture combusts by autoignition; and
during a second transition between operating modes, performing an injection during a compression stroke so that a second stratified mixture of air and fuel is formed; and performing a spark from the spark plug so that the second mixture combusts.
12. The method of claim 11, wherein the first transition mode is utilized for at least one cycle when transitioning from a spark ignition mode to a compression ignition mode.
13. The method of claim 11, wherein the second transition mode is utilized for at least one cycle when transitioning from a spark ignition mode to a compression ignition mode.
14. The method of claim 11, wherein the first transition mode is utilized for at least one cycle when transitioning from a compression ignition mode to a spark ignition mode.
15. The method of claim 11, wherein the second transition mode is utilized for at least one cycle when transitioning from a compression ignition mode to a spark ignition mode.
16. The method of claim 11, wherein the first transition mode is utilized for at least one cycle and later the second transition mode is utilized for at least one cycle when transitioning from a compression ignition mode to a spark ignition mode.
17. The method of claim 11, wherein the second transition mode is utilized for at least one cycle and later the first transition mode is utilized for at least one cycle, when transitioning from a spark ignition mode to a compression ignition mode.
18. A method of operating an internal combustion engine having a combustion chamber with a piston and a spark plug, comprising:
when transitioning between spark ignition combustion and autoignition combustion, creating a first mixture of air and fuel, adjusting an operating condition of the engine so that said first mixture of air and fuel in the combustion chamber approaches, but does not achieve, the autoignition temperature, and performing a spark from the spark plug so that at least a portion of said first mixture combusts to raise a remaining portion of said first mixture to said autoignition temperature; and
during said transition, performing an injection during a compression stroke so that a second stratified mixture of air and fuel is formed and performing a spark from the spark plug so that the second mixture combusts.
19. The method of claim 18, wherein said spark for said first mixture is performed after top dead center of piston position.
20. A method of operating an internal combustion engine having a combustion chamber with a piston and a spark plug, comprising:
when transitioning between spark ignition combustion and autoignition combustion, creating a first mixture of air and fuel, adjusting an operating condition of the engine so that said first mixture of air and fuel in the combustion chamber approaches, but does not achieve, the autoignition temperature, and performing a spark from the spark plug so that at least a portion of said first mixture combusts to raise a remaining portion of said first mixture to said autoignition temperature;
wherein said first mixture is created by performing a first injection during an intake stroke so that a lean homogeneous air and fuel region is created and performing a second injection during a compression stroke so that a less lean homogeneous air and fuel region is created substantially near the spark plug.