Solid polymer electrolyte ammonia sensor
AssigneeHamilton Sundstrand Corporation
InventorsLei Chen, Hsien-chi W. Niu, Joseph V. Mantese
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Abstract
An ammonia sensor that includes an ionic liquid impregnated sensing electrode (anode) and a cathode separated by a membrane. During operation, in the presence of ammonia, the anode and cathode generate current manifesting the electrochemical reaction of ammonia in the sensing electrode. Ionic liquids distributed in the ionomer film in the gas diffusion electrodes ensure the reactivity under wide range of environment conditions while maintaining the ability of the device to quantify ammonia concentration in the environment. The sensor can therefore sustain long time operation without internal humidification due to the non-volatility of the ionic liquids.
Claims20
An ammonia sensor, comprising:
- a gas diffusion sensing electrode comprising a first catalyst support, a first nanocatalyst, and a first ion-conducting ionomer film with porosity ranging from 20% to 80%, wherein the first nanocatalyst and the first ion-conducting ionomer film are supported by the first catalyst support and the ionomer is impregnated with ionic liquids;
- a membrane comprising an ion conducting polymer;
- a gas diffusion counter electrode comprising a second catalyst support, a second nanocatalyst, and a second ion-conducting ionomer film, wherein the second nanocatalyst and the second ion-conducting ionomer film are supported by the second catalyst support, wherein the membrane is directly interposed between the sensing electrode and the counter electrode;
- a first housing portion electrically coupled to the sensing electrode, wherein the first housing portion comprises an opening therein that exposes the sensing electrode to an environment;
- a second housing portion electrically coupled to the counter electrode,
- wherein the ammonia sensor is configured such that the sensing electrode can be electrically coupled to the counter electrode and the ammonia sensor is configured to determine a presence of ammonia in the environment.
A method for detecting the presence of environmental ammonia, comprising:
- providing a membrane comprising a polymer matrix, interstitial spaces within the polymer matrix, and an ionic liquid within the interstitial spaces;
- providing a gas diffusion sensing electrode comprising a first catalyst support, a first nanocatalyst, and a first ion-conducting ionomer film, wherein the first nanocatalyst and the first ion-conducting ionomer film are supported by the first catalyst support;
- providing a gas diffusion counter electrode comprising a second catalyst support, a second nanocatalyst, and a second ion-conducting ionomer film, wherein the second nanocatalyst and the second ion-conducting ionomer film are supported by the second catalyst support, wherein the membrane is directly interposed between the sensing electrode and the counter electrode;
- providing a first housing portion electrically coupled to the sensing electrode, wherein the first housing portion comprises an opening therein that exposes the sensing electrode to an environment;
- providing a second housing portion electrically coupled to the counter electrode;
- detecting the presence or absence of ionic conduction via the membrane between the first housing portion and the second housing portion, wherein charge transfer between the first housing portion and the second housing portion indicates the presence of environmental ammonia and the absence of ionic current between the first housing portion and the second housing portion indicates the absence of environmental ammonia.
Dependencies are inferred from the claim text.