Method for detecting an analyte gas using a gas sensor device comprising carbon nanotubes

Abstract

This invention relates generally to gas sensors comprising organized assemblies of carbon and non-carbon compounds. The invention also relates to devices containing such gas sensors and analysis units. In preferred embodiments, the organized assemblies of the instant invention take the form of nanorods or their aggregate forms. More preferably, a nanorod is made up of a carbon nanotube filled, coated, or both filled and coated by a non-carbon material. The invention further relates to a method for detecting or quantitating an analyte gas.

1 . A method for detecting or quantitating an analyte gas, comprising:
 flowing an analyte gas over a sensor comprising carbon nanotubes filled with one or more non-carbon materials comprising iron, platinum, or a combination thereof;   detecting and determining the concentration of the analyte gas by measuring the Electronic Property Response of the sensor due to the analyte gas using an analysis unit connected to the sensor, wherein the analyte gas is a carbon dioxide gas or a hydrogen gas.   
     
     
         2 . The method according to  claim 1 , wherein the sensor provides higher Electronic Property Response than a sensor comprising unfilled carbon nanotubes provides. 
     
     
         3 . The method according to  claim 1 , wherein said carbon nanotubes are single wall carbon nanotubes or multi wall carbon nanotubes. 
     
     
         4 . The method according to  claim 3 , wherein said carbon nanotubes are single wall carbon nanotubes with an outer diameter varying in the range of 1.0 nm to 1.8 nm. 
     
     
         5 . The method according to  claim 1 , wherein said Electronic Property Response is Resistive Response, Resistive Response derived from Circuit, or Capacitive Response derived from Circuit. 
     
     
         6 . The method according to  claim 1 , wherein said non-carbon material comprises iron. 
     
     
         7 . The method according to  claim 1 , wherein said non-carbon material comprises platinum. 
     
     
         8 . The method according to  claim 1 , wherein said carbon nanotubes are further coated with a second non-carbon material. 
     
     
         9 . The method according to  claim 1 , wherein the method provides at least one order of magnitude enhancement in sensitivity compared to a method using a sensor comprising unfilled carbon nanotubes. 
     
     
         10 . The method according to  claim 1 , wherein the analyte gas is a hydrogen gas and the method determines the concentration of the hydrogen gas at a minimum detection limit of 0.159-0.714 parts per billion. 
     
     
         11 . The method according to  claim 1 , wherein the analyte gas is a carbon dioxide gas and the method determines the concentration of the carbon dioxide gas at a minimum detection limit of 0.05-0.39 parts per billion. 
     
     
         12 . A method for detecting or quantitating carbon dioxide gas, comprising:
 flowing carbon dioxide gas over a sensor comprising carbon nanotubes filled with one or more non-carbon materials comprising palladium;   detecting and determining the concentration of the carbon dioxide gas by measuring the Electronic Property Response of the sensor due to the carbon dioxide gas using an analysis unit connected to the sensor;   wherein said carbon nanotubes are single wall carbon nanotubes with an outer diameter varying in the range of 1.0 nm to 1.8 nm.   
     
     
         13 . The method according to  claim 12 , wherein said carbon nanotubes are further coated with a second non-carbon material. 
     
     
         14 . The method according to  claim 12 , which detects and determines the concentration of carbon dioxide at a minimum detection limit of 0.05-0.39 parts per billion. 
     
     
         15 . A method for detecting or quantitating NO 2  gas, comprising:
 flowing NO 2  gas over a sensor comprising carbon nanotubes filled with one or more non-carbon materials comprising a titanium compound, iron, platinum, cobalt, nickel, or any combination thereof;   detecting and determining the concentration of the NO 2  gas by measuring the Electronic Property Response of the sensor due to the NO 2  gas using an analysis unit connected to the sensor.   
     
     
         16 . The method of  claim 15 , wherein the sensor provides higher Electronic Property Response than a sensor comprising unfilled carbon nanotubes provides. 
     
     
         17 . The method of  claim 15 , wherein said non-carbon material comprises a titanium compound having a formula TiH w B x N y O z , wherein w=0 to 2, x=0 to 2, y=0 to 1, and z=0 to 2. 
     
     
         18 . The method of  claim 15 , wherein said carbon nanotubes are further coated with one or more non-carbon materials comprising iron, platinum, palladium, cobalt, or nickel. 
     
     
         19 . The method according to  claim 15 , wherein said carbon nanotubes are single wall carbon nanotubes or multi wall carbon nanotubes. 
     
     
         20 . The method according to  claim 19 , wherein said carbon nanotubes are single wall carbon nanotubes with an outer diameter varying in the range of 1.0 nm to 1.8 nm.