Hydrogen gas sensors based on nanoparticle-decorated, patterned carbon nanotube ropes
AssigneeThe Regents of the University of California
InventorsReginald M. Penner, Xiaowei Li
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Abstract
Nanoparticle(NP)-decorated carbon nanotube (CNT) ropes used as sensing elements for hydrogen gas (H2) chemiresistors are described herein. The NP-decorated CNT rope sensors were prepared by dielectrophoretic deposition of a single semiconducting CNT rope followed by the electrodeposition of metal nanoparticles to highly disperse said nanoparticles on the CNT surfaces. The rope sensors produced a relative resistance change 20-30 times larger than what was observed at single, pure Pd nanowires. Thus, the rope sensors improved upon all H2 sensing metrics (speed, dynamic range, and limit-of-detection) relative to single Pd nanowires.
Claims6
A hydrogen gas (H2) sensor (105) for sensing H2 gas in air, said H2 sensor (105) comprising:
- a. a supporting substrate (110);
- b. a carbon nanotube (CNT) rope (130) electrodeposited onto the supporting substrate (110);
- c. at least two metal electrodes (140) disposed on the CNT rope (130), wherein a portion of the CNT rope (130) is disposed in-between the two metal electrodes (140);
- and
- d. metal nanoparticles (NPs) (135) electrodeposited onto the portion of the CNT rope (130) that is disposed between the two metal electrodes (140), wherein the metal NPs (135) have a mean particle diameter of about 4-9 nm, wherein said mean particle diameter size enables the H2 sensor (105) to detect H2 in air at an H2 concentration of at least 10 ppm.
A hydrogen gas (H2) sensor (105) for sensing H2 gas in air, said H2 sensor (105) comprising:
- a. a supporting substrate (110);
- b. a carbon nanotube (CNT) rope (130) electrodeposited onto the supporting substrate (110);
- c. at least two metal electrodes (140) electrodeposited on the CNT rope (130), wherein a portion of the CNT rope (130) is disposed in-between the two metal electrodes (140);
- and
- d. a photoresist layer (120) deposited on the two metal electrodes (140), CNT rope (130), and the supporting substrate (110);
- e. a window (150) formed through the photoresist layer (120) by lithographical patterning, wherein the window (150) exposes and isolates a portion of the CNT rope (130) disposed between the two metal electrodes (140);
- and
- metal nanoparticles (NPs) (135) electrodeposited onto the portion of the CNT rope (130) that is disposed between the two metal electrodes (140), wherein the metal NPs (135) have a mean particle diameter of about 4-10 nm, wherein said mean particle diameter size enables the H2 sensor (105) to detect H2 in air at an H2 concentration of at least 10 ppm.
A hydrogen gas (H2) sensor (105) for sensing H2 gas in air, said H2 sensor (105) comprising:
- a. a supporting substrate (110);
- b. a carbon nanotube (CNT) rope (130) electrodeposited onto the supporting substrate (110);
- c. at least two metal electrodes (140) electrodeposited on the CNT rope (130), wherein a portion of the CNT rope (130) is disposed in-between the two metal electrodes (140);
- and
- d. a photoresist layer (120) deposited on the two metal electrodes (140), CNT rope (130), and the supporting substrate (110);
- e. a window (150) formed through the photoresist layer (120) by lithographical patterning, wherein the window (150) exposes and isolates a portion of the CNT rope (130) disposed between the two metal electrodes (140);
- and
- palladium nanoparticles (135) electrodeposited onto the portion of the CNT rope (130) that is exposed and isolated, wherein said electrodepositing the palladium nanoparticles (135) utilizes a pulse electrodeposition process comprising applying about 50-400 voltage pulses, each pulse having an applied potential of about −0.8 V vs. saturated calomel electrode (SCE) and a pulse duration of about 0.1-0.5 second and being separated by about 1-2 second wait times, wherein said pulse electrodeposition process enables formation of the palladium nanoparticles (135) having a mean particle diameter of about 4-10 nm, and maximizes a density of the palladium nanoparticles (135) formed on the exposed and isolated portion of the CNT rope (130), thus producing an H2 sensor (105) capable of detecting H2 in air at an H2 concentration of at least 10 ppm.
Dependencies are inferred from the claim text.