Hydrogen-selective porous composite

1. A method for detecting molecular hydrogen (H 2 ), comprising:

providing a gas comprising H 2 ;

providing a H 2 -selective porous composite, the H 2 -selective porous composite comprising cerium oxide, the H 2 -selective porous composite being characterized by a percentage by weight of the cerium oxide of at least about 94%;

contacting the gas comprising H 2 to the H 2 -selective porous composite; and

selectively detecting H 2 in the gas comprising H 2 according to a decrease in an electrical resistance of the H 2 -selective porous composite.

2. The method of claim 1 , the cerium oxide being undoped cerium oxide.

3. The method of claim 1 , the H 2 -selective porous composite further comprising a metal oxide modifier, the metal oxide modifier comprising one or more of: tin oxide, indium oxide, titanium oxide, copper oxide, cobalt oxide, tungsten oxide, molybdenum oxide, nickel oxide, iron oxide, niobium oxide, vanadium oxide, and a transition metal oxide.

4. The method of claim 3 , the H 2 -selective porous composite being characterized by a percentage by weight of the metal oxide modifier of up to about 5%.

5. The method of claim 1 , the H 2 -selective porous composite being characterized by a percentage by weight of cerium oxide of at least about 95%.

6. The method of claim 1 , selectively detecting the H 2 comprising detecting the H 2 at a level in the gas comprising H 2 of at least about 0.1%.

7. The method of claim 1 , comprising selectively detecting H 2 in the gas comprising H 2 at a temperature of at least about 400° C.

8. The method of claim 1 , the H 2 -selective porous composite, when characterized at a temperature range of from about 400° C. to about 600° C. in simulated air at 0% relative humidity, comprising one or more of:

a percent sensitivity of at least about 22% to 1% H 2 in the simulated air;

a relative percent sensitivity of at least about 15% for 1% H 2 relative to 200 ppm carbon monoxide in the simulated air; and

a relative percent sensitivity of at least about 2% for 1% H 2 relative to 0.5% methane in the simulated air.

9. The method of claim 1 , the H 2 -selective porous composite comprising a response time of less than about ten seconds to reach about 90% of a maximum change in the electrical resistance when characterized at a temperature of about 400° C. in simulated air at 0% relative humidity, the response time starting upon introduction of 1% H 2 to the simulated air.

10. The method of claim 1 , the H 2 -selective porous composite comprising a noble metal promoter comprising one or more of: palladium, ruthenium, platinum, gold, rhodium, and iridium.

11. The method of claim 10 , the H 2 -selective porous composite comprising at least about 1 wt % of the noble metal promoter.

12. The method of claim 1 , the H 2 -selective porous composite substantially excluding a noble metal promoter.

13. The method of claim 1 , the H 2 -selective porous composite comprising:

the cerium oxide in the form of undoped cerium oxide;

a metal oxide modifier in contact with the undoped cerium oxide, the metal oxide modifier being present in an amount of up to about 5 wt % of the H 2 -selective porous composite; and

a noble metal promoter in contact with the undoped cerium oxide, the noble metal promoter being present in an amount of up to about 1 wt % of the H 2 -selective porous composite.

14. The method of claim 1 , the H 2 -selective porous composite characterized by:

the cerium oxide being in the form of undoped cerium oxide;

about 5 wt % of tin oxide in contact with the undoped cerium oxide; and

about 1 wt % of palladium in contact with the undoped cerium oxide.

15. A kit for detecting molecular hydrogen (H 2 ), comprising:

a H 2 gas sensor device, comprising:

a support;

electrodes on a first surface of the support; and

a H 2 -selective porous composite coated on the first surface of the support:

H 2 -selective porous composite being characterized by a percentage by weight of at least about 94% of a ceria composition that is one of: doped cerium oxide and undoped cerium oxide, and

the H 2 -selective porous composite contacting the electrodes such that an electrical resistance of the H 2 -selective porous composite is measurable at the electrodes,

provided that when the ceria composition is gadolinium doped ceria and the H 2 -selective porous composite excludes a noble metal promoter, the H 2 -selective porous composite comprises indium oxide, copper oxide, cobalt oxide, nickel oxide, iron oxide, niobium oxide, or vanadium oxide;

instructions, the instructions comprising:

directions to contact a gas comprising H 2 to the H 2 -selective porous composite of the H 2 gas sensor device; and

directions to selectively detect H 2 in the gas comprising H 2 by measuring a decrease in the electrical resistance of the H 2 -selective porous composite at the electrodes.

16. The kit of claim 15 , the support comprising one or more of: aluminum oxide, yttrium-stabilized zirconia, cerium oxide, gadolinium-doped ceria, magnesium aluminate, and magnesium oxide.

17. The kit of claim 15 , the H 2 gas sensor device further comprising an integral resistive heater.

18. The kit of claim 17 , the instructions further comprising directions to vary an electrical resistance of the resistive heater to control a sensitivity of the H 2 gas sensor device to relative humidity.

19. The kit of claim 17 , the support comprising one of:

a micro-tubular support, the resistive heater being located in the interior of the micro-tubular support; and

a planar support, the resistive heater being located on a second surface of the support opposite the first surface of the support.

20. The kit of claim 15 , the ceria composition being undoped cerium oxide.

21. The kit of claim 15 , the H 2 -selective porous composite further comprising a metal oxide modifier, the metal oxide modifier comprising one or more of: tin oxide, indium oxide, titanium oxide, copper oxide, cobalt oxide, tungsten oxide, molybdenum oxide, nickel oxide, iron oxide, niobium oxide, vanadium oxide, and a transition metal oxide.

22. The kit of claim 21 , the H 2 -selective porous composite being characterized by a percentage by weight of the metal oxide modifier of up to about 5%.

23. The kit of claim 15 , the H 2 -selective porous composite being characterized by a percentage by weight of cerium oxide of at least about 95%.

24. The kit of claim 15 , the instructions comprising directions to selectively detect the H 2 at a level in the gas comprising H 2 of at least about 0.1%.

25. The kit of claim 15 , the instructions comprising directions to selectively detect the H 2 in the gas comprising H 2 at a temperature of at least about 400° C.

26. The kit of claim 15 , the H 2 -selective porous composite, when characterized at a temperature range of from about 400° C. to about 600° C. in simulated air at 0% relative humidity, comprising one or more of:

a percent sensitivity of at least about 22% to 1% H 2 in the simulated air;

a relative percent sensitivity of at least about 15% for 1% H 2 relative to 200 ppm carbon monoxide in the simulated air; and

a relative percent sensitivity of at least about 2% for 1% H 2 relative to 0.5% methane in the simulated air.

27. The kit of claim 15 , the H 2 -selective porous composite comprising a response time of less than about ten seconds to reach about 90% of a maximum change in the electrical resistance when characterized at a temperature of about 400° C. in simulated air at 0% relative humidity, the response time starting upon introduction of 1% H 2 to the simulated air.

28. The kit of claim 15 , the H 2 -selective porous composite comprising the noble metal promoter comprising one or more of: palladium, ruthenium, platinum, gold, rhodium, and iridium.

29. The kit of claim 28 , the H 2 -selective porous composite comprising at least about 1 wt % of the noble metal promoter.

30. The kit of claim 15 , the H 2 -selective porous composite substantially excluding the noble metal promoter.

31. The kit of claim 15 , the H 2 -selective porous composite comprising:

the ceria composition in the form of undoped cerium oxide;

a metal oxide modifier in contact with the undoped cerium oxide, the metal oxide modifier being present in an amount of up to about 5 wt % of the H 2 -selective porous composite; and

the noble metal promoter in contact with the undoped cerium oxide, the noble metal promoter being present in an amount of up to about 1 wt % of the H 2 -selective porous composite.

32. The kit of claim 15 , the H 2 -selective porous composite characterized by:

the ceria composition being in the form of undoped cerium oxide;

about 5 wt % of tin oxide in contact with the undoped cerium oxide; and

further comprising about 1 wt % of palladium in contact with the undoped cerium oxide.

33. A molecular hydrogen (H 2 ) gas sensor device, comprising:

a support;

electrodes on a first surface of the support; and

a H 2 -selective porous composite coated on the first surface of the support:

the H 2 -selective porous composite being characterized by a percentage by weight of at least about 94% of a ceria composition that is one of: doped cerium oxide and undoped cerium oxide,

the H 2 -selective porous composite contacting the electrodes such that an electrical resistance of the H 2 -selective porous composite is measurable at the electrodes, and

the H 2 -selective porous composite comprising a metal oxide modifier in contact with the ceria composition, the metal oxide modifier being present in an amount of up to about 5 wt % of the H 2 -selective porous composite,

provided that when the ceria composition is gadolinium doped ceria and the H 2 -selective porous composite excludes a noble metal promoter, the metal oxide modifier comprises indium oxide, copper oxide, cobalt oxide, nickel oxide, iron oxide, niobium oxide, or vanadium oxide.

34. The H 2 gas sensor device of claim 33 , the support comprising one or more of: aluminum oxide, yttrium-stabilized zirconia, cerium oxide, gadolinium-doped ceria, magnesium aluminate, and magnesium oxide.

35. The H 2 gas sensor device of claim 33 , the H 2 gas sensor device further comprising an integral resistive heater.

36. The H 2 gas sensor device of claim 35 , the support comprising one of:

a micro-tubular support, the resistive heater being located in the interior of the micro-tubular support; and

a planar support, the resistive heater being located on a second surface of the support opposite the first surface of the support.

37. The H 2 gas sensor device of claim 33 , the metal oxide modifier comprising one or more of: tin oxide, indium oxide, titanium oxide, copper oxide, cobalt oxide, tungsten oxide, molybdenum oxide, nickel oxide, iron oxide, niobium oxide, vanadium oxide, and a transition metal oxide.

38. The H 2 gas sensor device of claim 33 , the H 2 -selective porous composite being characterized by a percentage by weight of the metal oxide modifier of up to about 2.5%.

39. The H 2 gas sensor device of claim 33 , the H 2 -selective porous composite being characterized by a percentage by weight of the ceria composition of at least about 95%.

40. The H 2 gas sensor device of claim 33 , the ceria composition being undoped cerium oxide.

41. The H 2 gas sensor device of claim 33 , the H 2 -selective porous composite comprising the noble metal promoter comprising one or more of: palladium, ruthenium, platinum, gold, rhodium, and iridium.

42. The H 2 gas sensor device of claim 41 , the H 2 -selective porous composite comprising at least about 1 wt % of the noble metal promoter.

43. The H 2 gas sensor device of claim 33 , the H 2 -selective porous composite substantially excluding the noble metal promoter.

44. The H 2 gas sensor device of claim 33 , the H 2 -selective porous composite comprising:

the ceria composition in the form of undoped cerium oxide;

the metal oxide modifier in contact with the undoped cerium oxide, the metal oxide modifier being present in an amount of up to about 5 wt % of the H 2 -selective porous composite; and

the noble metal promoter in contact with the undoped cerium oxide, the noble metal promoter being present in an amount of up to about 1 wt % of the H 2 -selective porous composite.

45. The H 2 gas sensor device of claim 33 , the H 2 -selective porous composite characterized by:

the ceria composition being in the form of undoped cerium oxide;

about 5 wt % of tin oxide in contact with the undoped cerium oxide; and

about 1 wt % of palladium in contact with the undoped cerium oxide.

46. A composition, comprising:

a molecular hydrogen (H 2 )-selective porous composite comprising:

a percentage by weight of at least about 94% of a ceria composition that is one of: doped cerium oxide and undoped cerium oxide,

a metal oxide modifier in contact with the ceria composition, the metal oxide modifier being present in an amount of up to about 5 wt % of the H 2 -selective porous composite,

provided that when the ceria composition is gadolinium doped ceria and the H 2 -selective porous composite excludes a noble metal promoter, the metal oxide modifier comprises indium oxide, copper oxide, cobalt oxide, nickel oxide, iron oxide, niobium oxide, or vanadium oxide.

47. The composition of claim 46 , the metal oxide modifier comprising one or more of: tin oxide, indium oxide, titanium oxide, copper oxide, cobalt oxide, tungsten oxide, molybdenum oxide, nickel oxide, iron oxide, niobium oxide, vanadium oxide, and a transition metal oxide.

48. The composition of claim 46 , the H 2 -selective porous composite being characterized by a percentage by weight of the metal oxide modifier of up to about 2.5%.

49. The composition of claim 46 , the H 2 -selective porous composite being characterized by a percentage by weight of the ceria composition of at least about 95%.

50. The composition of claim 46 , the ceria composition being undoped cerium oxide.

51. The composition of claim 50 , the H 2 -selective porous composite comprising the noble metal promoter comprising one or more of: palladium, ruthenium, platinum, gold, rhodium, and iridium.

52. The composition of claim 51 , the H 2 -selective porous composite comprising at least about 1 wt % of the noble metal promoter.

53. The composition of claim 46 , the H 2 -selective porous composite substantially excluding the noble metal promoter.

54. The composition of claim 46 , the H 2 -selective porous composite comprising:

the ceria composition in the form of undoped cerium oxide;

the metal oxide modifier in contact with the undoped cerium oxide, the metal oxide modifier being present in an amount of up to about 5 wt % of the H 2 -selective porous composite; and

further comprising the noble metal promoter in contact with the undoped cerium oxide, the noble metal promoter being present in an amount of up to about 1 wt % of the H 2 -selective porous composite.

55. The composition of claim 46 , the H 2 -selective porous composite characterized by:

the ceria composition being in the form of undoped cerium oxide;

about 5 wt % of tin oxide as the metal oxide modifier in contact with the undoped cerium oxide; and

further comprising about 1 wt % of palladium in contact with the undoped cerium oxide.