Hydrogen sensor using a solid hydrogen ion conducting electrolyte

Abstract

A reliable gaseous hydrogen detection and measuring device which is simple, easy to use, does not require any reference gas supply, and which can be of reasonably rugged construction. The device utilizes a disc comprising a solid state ceramic hydronium conductor of the general formula Na(H 3 O)Zr 2 Si x P (3−x) O 12 Na( H 3 O ) x Zr 2 Si x P (3−x) O 12 together with a silver based electrode system on one side, and a catalytic noble metal electrode, such as platinum, on the other. By measurement of the output voltage across the electrodes, both the presence, and the amount, of hydrogen in a gaseous system can be determined.

We claim:  
     
       1. A hydrogen detection device comprising in combination: 
       (a) a body of phosphate bonded ceramic electrolyte of the general formula Na(H 3 O) x Zr 2 Si x P (3−x) O 12  having a first face spaced apart from a second face;  
       (b) a layer of platinum on the first face of the body in electrical contact with the ceramic electrolyte  a catalytic noble metal electrode layer on the first face of the body in electrical contact with the ceramic electrolyte;  
       (c) a silver ion modified layer on and in the second face of the body;  
       (d) a silver electrode in contact with the silver ion modified layer; and  
       (e) conductive leads electrically connected to each of the faces;  
       whereby the emf generated when the ceramic body is exposed to hydrogen gas is measured. 
     
     
       2. A hydrogen detection device according to  claim 1  wherein the first and second spaced apart faces on the ceramic body are substantially parallel to each other. 
     
     
       3. A hydrogen detection device according to  claim 1  wherein the first and second faces are each substantially flat. 
     
     
       4. A hydrogen detection device according to  claim 1  wherein the first and second spaced apart faces on the ceramic body are substantially parallel to each other, and wherein the first and second faces are each substantially flat. 
     
     
       5. A hydrogen detection device according to  claim 4  wherein the ceramic body is disc shaped, and the first and second faces comprise the two faces of the disc. 
     
     
       6. A hydrogen detection device according to  claim 1  wherein the silver electrode comprises a silver containing conductive cement applied over the silver ion modified layer. 
     
     
       7. A hydrogen detection device according to  claim 1  wherein the two conductive leads are attached to each of the platinum  noble metal layer and the silver electrode by means of a conductive cement. 
     
     
       8. A hydrogen detection device according to  claim 1  wherein the same silver containing conducting cement is used as both the silver electrode and to attach the two conductive leads. 
     
     
       9. A hydrogen detection device according to  claim 1  wherein the two conductive leads are both silver. 
     
     
       10. A hydrogen detection device according to  claim 1  wherein in the body of ceramic electrolyte of the general formula Na(H 3 O) x Zr 2 Si x P (3−x) O 12 , x has a value of from about 1.3 to about 2.2. 
     
     
       11. A hydrogen detection device according to  claim 10  wherein x has a value of about 1.5. 
     
     
       12. A method of detecting hydrogen in a gaseous system which comprises exposing a detection device comprising in combination: 
       (a) a body of phosphate bonded ceramic electrolyte of the general formula Na(H 3 O) x Zr 2 Si x P (3−x) O 12  having a first face spaced apart from a second face;  
       (b) a layer of platinum  catalytic noble metal layer on the first face of the body in electrical contact with the ceramic electrolyte;  
       (c) a silver ion modified layer on and in the second face of the body;  
       (d) a silver electrode in contact with the silver ion modified layer; and  
       (e) conductive leads electrically connected to each of the faces;  
       to the gaseous system, and measuring the emf generated across the two conductive leads. 
     
     
       13. A method of measuring the concentration of hydrogen in a gaseous system which comprises: 
       (i) exposing a detection device comprising in combination:  
       (a) a body of ceramic electrolyte of the general formula Na (1+x) Zr 2 Si x P (3−x) O 12  having a first face spaced apart from a second face;  
       (b) a layer of platinum  catalytic noble metal layer on the first face of the body in electrical contact with the ceramic electrolyte;  
       (c) a silver ion modified layer on and in the second face of the body;  
       (d) a silver electrode in contact with the silver ion modified layer; and  
       (e) conductive leads electrically connected to each of the faces;  
       to a plurality of gaseous systems each containing known amounts of hydrogen; 
       (ii) measuring the emf generated across the conductive leads by exposure to each gaseous system to provide a calibration curve for the device;  
       (iii) exposing the device to a gaseous system containing an unknown amount of hydrogen;  
       (iv) measuring the emf generated on exposure to gaseous system in step (iii); and  
       (v) comparing the emf measured in step (iv) with the calibration curve obtained in step (ii).  
     
     
       14. A method according to  claim 12  wherein the noble metal is chosen from the group consisting of platinum and palladium.  
     
     
       15. A method according to  claim 14  wherein the noble metal is platinum.  
     
     
       16. A method according to  claim 14  wherein the noble metal is palladium.  
     
     
       17. A method according to  claim 13  wherein the noble metal is chosen from the group consisting of platinum and palladium.  
     
     
       18. A method according to  claim 17  wherein the noble metal is platinum.  
     
     
       19. A method according to  claim 17  wherein the noble metal is palladium.  
     
     
       20. A hydrogen detection device according to  claim 1  wherein the noble metal is chosen from the group consisting of platinum and palladium.  
     
     
       21. A hydrogen detection device according to  claim 20  wherein the noble metal is platinum.  
     
     
       22. A hydrogen detection device according to  claim 20  wherein the noble metal is palladium.  
     
     
       23. A hydrogen detection device according to  claim 1  wherein the first and second spaced apart faces on the ceramic body are substantially parallel to each other.  
     
     
       24. A hydrogen detection device according to  claim 1  wherein the first and second faces are each substantially flat.