Sensing element and method of making the same

Abstract

Disclosed herein is a sensing element comprising: an electrochemical cell; wherein the sensing element comprises a metal selected from the group consisting of Pd and alloys and combinations comprising at least one of the foregoing; and wherein the electrically conductive element is thermally stable at temperatures of greater than or equal to about 1,200° C.

1 . A sensing element, comprising: 
 a sensing electrode and a reference electrode in physical contact with an electrolyte; and    an electrically conductive element, wherein the electrically conductive element comprises a component selected from the group consisting of a ground plane, a lead, a via, a contact pad, a resistor, and combinations comprising at least one of the foregoing components;    wherein the electrically conductive element comprises irregularly shaped Pd.    
   
   
       2 . The sensor element of  claim 1 , wherein the electrically conductive element comprises greater than or equal to about 50 wt. % Pd, based upon the total weight of the electrically conductive element.  
   
   
       3 . The sensing element of  claim 1 , wherein the electrically conductive element comprises about 0.5 wt. % to about 25 wt. % of the metal oxide, based the total weight of the electrically conductive element.  
   
   
       4 . The sensing element of  claim 1 , wherein the metal oxide is selected from the group consisting of zirconia, yttria, alumina, lanthana, ceria, magnesia, scandia, and combinations comprising at least one of the foregoing.  
   
   
       5 . The sensing element of  claim 1 , wherein the electrically conductive element comprises a sheet resistivity of less than or equal to about 6×10 −3  μΩ/cm.  
   
   
       6 . The sensing element of  claim 5 , wherein the sheet resistivity is less than or equal to about 4×10 −3  μΩ/cm.  
   
   
       7 . The sensing element of  claim 6 , wherein the sheet resistivity is less than or equal to about 3×10 −3  μΩ/cm.  
   
   
       8 . The sensing element of  claim 1 , wherein the electrically conductive element is thermally stable at temperatures of about 1,200 to about 1,530° C.  
   
   
       9 . The sensing element of  claim 1 , wherein the Pd has a surface area of about 0.5 m 2 /g to about 5.0 m 2 /g.  
   
   
       10 . The sensing element of  claim 9 , wherein the surface area is about 1 m 2 /g to about 4.0 m 2 /g.  
   
   
       11 . The sensing element of  claim 10 , wherein the surface area is about 2.0 m 2 /g to about 3.0 m 2 /g.  
   
   
       12 . The sensing element of  claim 1 , wherein the electrically conductive element further comprises about 0.25 wt % to about 20 wt % of a metal selected from the group consisting of Pt, Rh, Ir, as well as combinations comprising at least one of the foregoing metals, wherein the weight is based upon a total weight of the electrically conductive element.  
   
   
       13 . The sensing element of  claim 12 , wherein the electrically conductive element comprises about 0.25 wt % to about 10 wt % of metal.  
   
   
       14 . The sensing element of  claim 12 , wherein the metal is Rh.  
   
   
       15 . The sensing element of  claim 12 , wherein the metal and the Pd are a solid solution.  
   
   
       16 . A sensing element, comprising: 
 a sensing electrode and a reference electrode in physical contact with an electrolyte; and    an electrically conductive element, wherein the electrically conductive element comprises a component selected from the group consisting of a ground plane, a lead, a via, a contact pad, a resistor, and combinations comprising at least one of the foregoing components;    wherein the electrically conductive element comprises Pd having a surface area of about 0.5 m 2 /g to about 5.0 m 2 /g.    
   
   
       17 . A method of making a sensing element, comprising: 
 disposing a sensing electrode and a reference electrode in physical contact with an electrolyte;    forming a conductive element precursor material comprising Pd having a surface area of about 0.5 m 2 /g to about 5.0 m 2 /g;    disposing the precursor material on a supporting surface to define an electrically conductive element; and    heating the precursor material to a temperature of greater than or equal to about 1,450° C. for a sufficient period of time to sinter the precursor material and form the sensing element.    
   
   
       18 . The method of  claim 17 , wherein the electrically conductive element is a sensing lead in physical contact with the sensing element, and further comprising disposing additional precursor material in physical contact with the reference electrode to form a reference lead.